From bd3bff9e20f454b242d979ec2f9a4dca0d5fa06f Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:20:41 +0200 Subject: sched: add latency tracer callbacks to the scheduler add 3 lightweight callbacks to the tracer backend. zero impact if tracing is turned off. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index cfa222a9153..463dcdb36ef 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2467,6 +2467,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) out_activate: #endif /* CONFIG_SMP */ + ftrace_wake_up_task(p, rq->curr); schedstat_inc(p, se.nr_wakeups); if (sync) schedstat_inc(p, se.nr_wakeups_sync); @@ -2611,6 +2612,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) p->sched_class->task_new(rq, p); inc_nr_running(rq); } + ftrace_wake_up_new_task(p, rq->curr); check_preempt_curr(rq, p); #ifdef CONFIG_SMP if (p->sched_class->task_wake_up) @@ -2783,6 +2785,7 @@ context_switch(struct rq *rq, struct task_struct *prev, struct mm_struct *mm, *oldmm; prepare_task_switch(rq, prev, next); + ftrace_ctx_switch(prev, next); mm = next->mm; oldmm = prev->active_mm; /* -- cgit v1.2.3-70-g09d2 From 7c731e0a495e25e79dc1e9e68772a67a55721a65 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 12 May 2008 21:20:41 +0200 Subject: ftrace: make the task state char-string visible to all The tracer wants to be able to convert the state number into a user visible character. This patch pulls that conversion string out the scheduler into the header. This way if it were to ever change, other parts of the kernel will know. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/sched.h | 2 ++ kernel/sched.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 717cab8a0c8..6e26f1fdbfe 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2237,6 +2237,8 @@ static inline void mm_init_owner(struct mm_struct *mm, struct task_struct *p) } #endif /* CONFIG_MM_OWNER */ +#define TASK_STATE_TO_CHAR_STR "RSDTtZX" + #endif /* __KERNEL__ */ #endif diff --git a/kernel/sched.c b/kernel/sched.c index 463dcdb36ef..73e60085236 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5729,7 +5729,7 @@ out_unlock: return retval; } -static const char stat_nam[] = "RSDTtZX"; +static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; void sched_show_task(struct task_struct *p) { -- cgit v1.2.3-70-g09d2 From 6cd8a4bb2f97527a9ceb30bc77ea4e959c6a95e3 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 12 May 2008 21:20:42 +0200 Subject: ftrace: trace preempt off critical timings Add preempt off timings. A lot of kernel core code is taken from the RT patch latency trace that was written by Ingo Molnar. This adds "preemptoff" and "preemptirqsoff" to /debugfs/tracing/available_tracers Now instead of just tracing irqs off, preemption off can be selected to be recorded. When this is selected, it shares the same files as irqs off timings. One can either trace preemption off, irqs off, or one or the other off. By echoing "preemptoff" into /debugfs/tracing/current_tracer, recording of preempt off only is performed. "irqsoff" will only record the time irqs are disabled, but "preemptirqsoff" will take the total time irqs or preemption are disabled. Runtime switching of these options is now supported by simpling echoing in the appropriate trace name into /debugfs/tracing/current_tracer. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/process_32.c | 3 + include/linux/ftrace.h | 8 ++ include/linux/irqflags.h | 3 +- include/linux/preempt.h | 2 +- kernel/sched.c | 24 +++++- kernel/trace/Kconfig | 25 ++++++ kernel/trace/Makefile | 1 + kernel/trace/trace_irqsoff.c | 184 +++++++++++++++++++++++++++++++------------ 8 files changed, 197 insertions(+), 53 deletions(-) (limited to 'kernel/sched.c') diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index f8476dfbb60..a30aa1f2607 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -185,7 +185,10 @@ void cpu_idle(void) local_irq_disable(); __get_cpu_var(irq_stat).idle_timestamp = jiffies; + /* Don't trace irqs off for idle */ + stop_critical_timings(); idle(); + start_critical_timings(); } tick_nohz_restart_sched_tick(); preempt_enable_no_resched(); diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 0a20445dcbc..740c97dcf9c 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -58,4 +58,12 @@ extern void mcount(void); # define time_hardirqs_off(a0, a1) do { } while (0) #endif +#ifdef CONFIG_PREEMPT_TRACER + extern void notrace trace_preempt_on(unsigned long a0, unsigned long a1); + extern void notrace trace_preempt_off(unsigned long a0, unsigned long a1); +#else +# define trace_preempt_on(a0, a1) do { } while (0) +# define trace_preempt_off(a0, a1) do { } while (0) +#endif + #endif /* _LINUX_FTRACE_H */ diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h index 5b711d4e9fd..2b1c2e58566 100644 --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -41,7 +41,8 @@ # define INIT_TRACE_IRQFLAGS #endif -#ifdef CONFIG_IRQSOFF_TRACER +#if defined(CONFIG_IRQSOFF_TRACER) || \ + defined(CONFIG_PREEMPT_TRACER) extern void stop_critical_timings(void); extern void start_critical_timings(void); #else diff --git a/include/linux/preempt.h b/include/linux/preempt.h index 36b03d50bf4..72b1a10a59b 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -10,7 +10,7 @@ #include #include -#ifdef CONFIG_DEBUG_PREEMPT +#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER) extern void add_preempt_count(int val); extern void sub_preempt_count(int val); #else diff --git a/kernel/sched.c b/kernel/sched.c index 73e60085236..328494e28df 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -70,6 +70,7 @@ #include #include #include +#include #include #include @@ -4365,26 +4366,44 @@ void scheduler_tick(void) #endif } -#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) +#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ + defined(CONFIG_PREEMPT_TRACER)) + +static inline unsigned long get_parent_ip(unsigned long addr) +{ + if (in_lock_functions(addr)) { + addr = CALLER_ADDR2; + if (in_lock_functions(addr)) + addr = CALLER_ADDR3; + } + return addr; +} void __kprobes add_preempt_count(int val) { +#ifdef CONFIG_DEBUG_PREEMPT /* * Underflow? */ if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) return; +#endif preempt_count() += val; +#ifdef CONFIG_DEBUG_PREEMPT /* * Spinlock count overflowing soon? */ DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK - 10); +#endif + if (preempt_count() == val) + trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); } EXPORT_SYMBOL(add_preempt_count); void __kprobes sub_preempt_count(int val) { +#ifdef CONFIG_DEBUG_PREEMPT /* * Underflow? */ @@ -4396,7 +4415,10 @@ void __kprobes sub_preempt_count(int val) if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK))) return; +#endif + if (preempt_count() == val) + trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); preempt_count() -= val; } EXPORT_SYMBOL(sub_preempt_count); diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 896df1cf6ad..6430016b98e 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -44,6 +44,31 @@ config IRQSOFF_TRACER echo 0 > /debugfs/tracing/tracing_max_latency + (Note that kernel size and overhead increases with this option + enabled. This option and the preempt-off timing option can be + used together or separately.) + +config PREEMPT_TRACER + bool "Preemption-off Latency Tracer" + default n + depends on GENERIC_TIME + depends on PREEMPT + select TRACING + select TRACER_MAX_TRACE + help + This option measures the time spent in preemption off critical + sections, with microsecond accuracy. + + The default measurement method is a maximum search, which is + disabled by default and can be runtime (re-)started + via: + + echo 0 > /debugfs/tracing/tracing_max_latency + + (Note that kernel size and overhead increases with this option + enabled. This option and the irqs-off timing option can be + used together or separately.) + config SCHED_TRACER bool "Scheduling Latency Tracer" depends on DEBUG_KERNEL diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 46be8647fb6..3fec653d653 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_TRACING) += trace.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o obj-$(CONFIG_FTRACE) += trace_functions.o obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o +obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o libftrace-y := ftrace.o diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index a9131b0cf1a..8b1231633dc 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -21,6 +21,36 @@ static struct trace_array *irqsoff_trace __read_mostly; static int tracer_enabled __read_mostly; +static DEFINE_PER_CPU(int, tracing_cpu); + +enum { + TRACER_IRQS_OFF = (1 << 1), + TRACER_PREEMPT_OFF = (1 << 2), +}; + +static int trace_type __read_mostly; + +#ifdef CONFIG_PREEMPT_TRACER +static inline int notrace +preempt_trace(void) +{ + return ((trace_type & TRACER_PREEMPT_OFF) && preempt_count()); +} +#else +# define preempt_trace() (0) +#endif + +#ifdef CONFIG_IRQSOFF_TRACER +static inline int notrace +irq_trace(void) +{ + return ((trace_type & TRACER_IRQS_OFF) && + irqs_disabled()); +} +#else +# define irq_trace() (0) +#endif + /* * Sequence count - we record it when starting a measurement and * skip the latency if the sequence has changed - some other section @@ -44,14 +74,11 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip) long disabled; int cpu; - if (likely(!tracer_enabled)) + if (likely(!__get_cpu_var(tracing_cpu))) return; local_save_flags(flags); - if (!irqs_disabled_flags(flags)) - return; - cpu = raw_smp_processor_id(); data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); @@ -171,23 +198,29 @@ start_critical_timing(unsigned long ip, unsigned long parent_ip) if (likely(!tracer_enabled)) return; + if (__get_cpu_var(tracing_cpu)) + return; + cpu = raw_smp_processor_id(); data = tr->data[cpu]; if (unlikely(!data) || unlikely(!data->trace) || - data->critical_start || atomic_read(&data->disabled)) + atomic_read(&data->disabled)) return; atomic_inc(&data->disabled); data->critical_sequence = max_sequence; data->preempt_timestamp = now(cpu); - data->critical_start = parent_ip; + data->critical_start = parent_ip ? : ip; tracing_reset(data); local_save_flags(flags); + ftrace(tr, data, ip, parent_ip, flags); + __get_cpu_var(tracing_cpu) = 1; + atomic_dec(&data->disabled); } @@ -199,7 +232,13 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) struct trace_array_cpu *data; unsigned long flags; - if (likely(!tracer_enabled)) + /* Always clear the tracing cpu on stopping the trace */ + if (unlikely(__get_cpu_var(tracing_cpu))) + __get_cpu_var(tracing_cpu) = 0; + else + return; + + if (!tracer_enabled) return; cpu = raw_smp_processor_id(); @@ -212,49 +251,35 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip) atomic_inc(&data->disabled); local_save_flags(flags); ftrace(tr, data, ip, parent_ip, flags); - check_critical_timing(tr, data, parent_ip, cpu); + check_critical_timing(tr, data, parent_ip ? : ip, cpu); data->critical_start = 0; atomic_dec(&data->disabled); } +/* start and stop critical timings used to for stoppage (in idle) */ void notrace start_critical_timings(void) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (preempt_trace() || irq_trace()) start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); } void notrace stop_critical_timings(void) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (preempt_trace() || irq_trace()) stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); } +#ifdef CONFIG_IRQSOFF_TRACER #ifdef CONFIG_PROVE_LOCKING void notrace time_hardirqs_on(unsigned long a0, unsigned long a1) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (!preempt_trace() && irq_trace()) stop_critical_timing(a0, a1); } void notrace time_hardirqs_off(unsigned long a0, unsigned long a1) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (!preempt_trace() && irq_trace()) start_critical_timing(a0, a1); } @@ -289,49 +314,46 @@ inline void print_irqtrace_events(struct task_struct *curr) */ void notrace trace_hardirqs_on(void) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (!preempt_trace() && irq_trace()) stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1); } EXPORT_SYMBOL(trace_hardirqs_on); void notrace trace_hardirqs_off(void) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (!preempt_trace() && irq_trace()) start_critical_timing(CALLER_ADDR0, CALLER_ADDR1); } EXPORT_SYMBOL(trace_hardirqs_off); void notrace trace_hardirqs_on_caller(unsigned long caller_addr) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (!preempt_trace() && irq_trace()) stop_critical_timing(CALLER_ADDR0, caller_addr); } EXPORT_SYMBOL(trace_hardirqs_on_caller); void notrace trace_hardirqs_off_caller(unsigned long caller_addr) { - unsigned long flags; - - local_save_flags(flags); - - if (irqs_disabled_flags(flags)) + if (!preempt_trace() && irq_trace()) start_critical_timing(CALLER_ADDR0, caller_addr); } EXPORT_SYMBOL(trace_hardirqs_off_caller); #endif /* CONFIG_PROVE_LOCKING */ +#endif /* CONFIG_IRQSOFF_TRACER */ + +#ifdef CONFIG_PREEMPT_TRACER +void notrace trace_preempt_on(unsigned long a0, unsigned long a1) +{ + stop_critical_timing(a0, a1); +} + +void notrace trace_preempt_off(unsigned long a0, unsigned long a1) +{ + start_critical_timing(a0, a1); +} +#endif /* CONFIG_PREEMPT_TRACER */ static void start_irqsoff_tracer(struct trace_array *tr) { @@ -345,7 +367,7 @@ static void stop_irqsoff_tracer(struct trace_array *tr) tracer_enabled = 0; } -static void irqsoff_tracer_init(struct trace_array *tr) +static void __irqsoff_tracer_init(struct trace_array *tr) { irqsoff_trace = tr; /* make sure that the tracer is visibel */ @@ -382,6 +404,13 @@ static void notrace irqsoff_tracer_close(struct trace_iterator *iter) start_irqsoff_tracer(iter->tr); } +#ifdef CONFIG_IRQSOFF_TRACER +static void irqsoff_tracer_init(struct trace_array *tr) +{ + trace_type = TRACER_IRQS_OFF; + + __irqsoff_tracer_init(tr); +} static struct tracer irqsoff_tracer __read_mostly = { .name = "irqsoff", @@ -392,10 +421,65 @@ static struct tracer irqsoff_tracer __read_mostly = .ctrl_update = irqsoff_tracer_ctrl_update, .print_max = 1, }; +# define register_irqsoff(trace) register_tracer(&trace) +#else +# define register_irqsoff(trace) do { } while (0) +#endif + +#ifdef CONFIG_PREEMPT_TRACER +static void preemptoff_tracer_init(struct trace_array *tr) +{ + trace_type = TRACER_PREEMPT_OFF; + + __irqsoff_tracer_init(tr); +} + +static struct tracer preemptoff_tracer __read_mostly = +{ + .name = "preemptoff", + .init = preemptoff_tracer_init, + .reset = irqsoff_tracer_reset, + .open = irqsoff_tracer_open, + .close = irqsoff_tracer_close, + .ctrl_update = irqsoff_tracer_ctrl_update, + .print_max = 1, +}; +# define register_preemptoff(trace) register_tracer(&trace) +#else +# define register_preemptoff(trace) do { } while (0) +#endif + +#if defined(CONFIG_IRQSOFF_TRACER) && \ + defined(CONFIG_PREEMPT_TRACER) + +static void preemptirqsoff_tracer_init(struct trace_array *tr) +{ + trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF; + + __irqsoff_tracer_init(tr); +} + +static struct tracer preemptirqsoff_tracer __read_mostly = +{ + .name = "preemptirqsoff", + .init = preemptirqsoff_tracer_init, + .reset = irqsoff_tracer_reset, + .open = irqsoff_tracer_open, + .close = irqsoff_tracer_close, + .ctrl_update = irqsoff_tracer_ctrl_update, + .print_max = 1, +}; + +# define register_preemptirqsoff(trace) register_tracer(&trace) +#else +# define register_preemptirqsoff(trace) do { } while (0) +#endif __init static int init_irqsoff_tracer(void) { - register_tracer(&irqsoff_tracer); + register_irqsoff(irqsoff_tracer); + register_preemptoff(preemptoff_tracer); + register_preemptirqsoff(preemptirqsoff_tracer); return 0; } -- cgit v1.2.3-70-g09d2 From 8ac0fca4ccb355ce50471d7aa3f10f5900b28b95 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:20:51 +0200 Subject: ftrace: sched tracer fix Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/sched.h | 6 ------ kernel/sched.c | 2 +- kernel/trace/trace_sched_wakeup.c | 13 +++---------- 3 files changed, 4 insertions(+), 17 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 6e26f1fdbfe..05744f9cb09 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2130,17 +2130,11 @@ ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next) #ifdef CONFIG_SCHED_TRACER extern void ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr); -extern void -ftrace_wake_up_new_task(struct task_struct *wakee, struct task_struct *curr); #else static inline void ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr) { } -static inline void -ftrace_wake_up_new_task(struct task_struct *wakee, struct task_struct *curr) -{ -} #endif extern long sched_setaffinity(pid_t pid, const cpumask_t *new_mask); diff --git a/kernel/sched.c b/kernel/sched.c index 328494e28df..53ab1174664 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2613,7 +2613,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) p->sched_class->task_new(rq, p); inc_nr_running(rq); } - ftrace_wake_up_new_task(p, rq->curr); + ftrace_wake_up_task(p, rq->curr); check_preempt_curr(rq, p); #ifdef CONFIG_SMP if (p->sched_class->task_wake_up) diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 87fa7b253b5..2a012423f9d 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -201,20 +201,13 @@ out: atomic_dec(&tr->data[cpu]->disabled); } -void -wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr) +void wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr) { if (likely(!tracer_enabled)) return; - wakeup_check_start(wakeup_trace, wakee, curr); -} - -void -ftrace_wake_up_new_task(struct task_struct *wakee, struct task_struct *curr) -{ - if (likely(!tracer_enabled)) - return; + tracing_record_cmdline(curr); + tracing_record_cmdline(wakee); wakeup_check_start(wakeup_trace, wakee, curr); } -- cgit v1.2.3-70-g09d2 From 4e65551905fb0300ae7e667cbaa41ee2e3f29a13 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:20:52 +0200 Subject: ftrace: sched tracer, trace full rbtree Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/sched.h | 32 ++++++++++++++++------- kernel/sched.c | 35 ++++++++++++++++++++++--- kernel/trace/trace.c | 55 ++++++++++++++++----------------------- kernel/trace/trace.h | 14 ++++++++++ kernel/trace/trace_sched_switch.c | 24 +++++++++++------ 5 files changed, 108 insertions(+), 52 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 05744f9cb09..652d380ae56 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2119,20 +2119,34 @@ static inline void arch_pick_mmap_layout(struct mm_struct *mm) #ifdef CONFIG_CONTEXT_SWITCH_TRACER extern void -ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next); +ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next); +extern void +ftrace_wake_up_task(void *rq, struct task_struct *wakee, + struct task_struct *curr); +extern void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data); +extern void +__trace_special(void *__tr, void *__data, + unsigned long arg1, unsigned long arg2, unsigned long arg3); #else static inline void -ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next) +ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next) +{ +} +static inline void +sched_trace_special(unsigned long p1, unsigned long p2, unsigned long p3) +{ +} +static inline void +ftrace_wake_up_task(void *rq, struct task_struct *wakee, + struct task_struct *curr) +{ +} +static inline void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) { } -#endif - -#ifdef CONFIG_SCHED_TRACER -extern void -ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr); -#else static inline void -ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr) +__trace_special(void *__tr, void *__data, + unsigned long arg1, unsigned long arg2, unsigned long arg3) { } #endif diff --git a/kernel/sched.c b/kernel/sched.c index 53ab1174664..b9208a0e33a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2394,6 +2394,35 @@ static int sched_balance_self(int cpu, int flag) #endif /* CONFIG_SMP */ +#ifdef CONFIG_CONTEXT_SWITCH_TRACER + +void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) +{ + struct sched_entity *se; + struct task_struct *p; + struct rb_node *curr; + struct rq *rq = __rq; + + curr = first_fair(&rq->cfs); + if (!curr) + return; + + while (curr) { + se = rb_entry(curr, struct sched_entity, run_node); + if (!entity_is_task(se)) + continue; + + p = task_of(se); + + __trace_special(__tr, __data, + p->pid, p->se.vruntime, p->se.sum_exec_runtime); + + curr = rb_next(curr); + } +} + +#endif + /*** * try_to_wake_up - wake up a thread * @p: the to-be-woken-up thread @@ -2468,7 +2497,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) out_activate: #endif /* CONFIG_SMP */ - ftrace_wake_up_task(p, rq->curr); + ftrace_wake_up_task(rq, p, rq->curr); schedstat_inc(p, se.nr_wakeups); if (sync) schedstat_inc(p, se.nr_wakeups_sync); @@ -2613,7 +2642,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) p->sched_class->task_new(rq, p); inc_nr_running(rq); } - ftrace_wake_up_task(p, rq->curr); + ftrace_wake_up_task(rq, p, rq->curr); check_preempt_curr(rq, p); #ifdef CONFIG_SMP if (p->sched_class->task_wake_up) @@ -2786,7 +2815,7 @@ context_switch(struct rq *rq, struct task_struct *prev, struct mm_struct *mm, *oldmm; prepare_task_switch(rq, prev, next); - ftrace_ctx_switch(prev, next); + ftrace_ctx_switch(rq, prev, next); mm = next->mm; oldmm = prev->active_mm; /* diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0e4b7119e26..65173b14b91 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -66,7 +66,18 @@ static struct tracer *current_trace __read_mostly; static int max_tracer_type_len; static DEFINE_MUTEX(trace_types_lock); -static DECLARE_WAIT_QUEUE_HEAD (trace_wait); +static DECLARE_WAIT_QUEUE_HEAD(trace_wait); + +unsigned long trace_flags = TRACE_ITER_PRINT_PARENT; + +/* + * FIXME: where should this be called? + */ +void trace_wake_up(void) +{ + if (!(trace_flags & TRACE_ITER_BLOCK)) + wake_up(&trace_wait); +} #define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry)) @@ -103,18 +114,6 @@ enum trace_flag_type { TRACE_FLAG_SOFTIRQ = 0x08, }; -enum trace_iterator_flags { - TRACE_ITER_PRINT_PARENT = 0x01, - TRACE_ITER_SYM_OFFSET = 0x02, - TRACE_ITER_SYM_ADDR = 0x04, - TRACE_ITER_VERBOSE = 0x08, - TRACE_ITER_RAW = 0x10, - TRACE_ITER_HEX = 0x20, - TRACE_ITER_BIN = 0x40, - TRACE_ITER_BLOCK = 0x80, - TRACE_ITER_STACKTRACE = 0x100, -}; - #define TRACE_ITER_SYM_MASK \ (TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR) @@ -132,8 +131,6 @@ static const char *trace_options[] = { NULL }; -static unsigned trace_flags = TRACE_ITER_PRINT_PARENT; - static DEFINE_SPINLOCK(ftrace_max_lock); /* @@ -660,9 +657,6 @@ trace_function(struct trace_array *tr, struct trace_array_cpu *data, entry->fn.ip = ip; entry->fn.parent_ip = parent_ip; spin_unlock_irqrestore(&data->lock, irq_flags); - - if (!(trace_flags & TRACE_ITER_BLOCK)) - wake_up(&trace_wait); } void @@ -673,10 +667,14 @@ ftrace(struct trace_array *tr, struct trace_array_cpu *data, trace_function(tr, data, ip, parent_ip, flags); } +#ifdef CONFIG_CONTEXT_SWITCH_TRACER + void -trace_special(struct trace_array *tr, struct trace_array_cpu *data, - unsigned long arg1, unsigned long arg2, unsigned long arg3) +__trace_special(void *__tr, void *__data, + unsigned long arg1, unsigned long arg2, unsigned long arg3) { + struct trace_array_cpu *data = __data; + struct trace_array *tr = __tr; struct trace_entry *entry; unsigned long irq_flags; @@ -688,11 +686,10 @@ trace_special(struct trace_array *tr, struct trace_array_cpu *data, entry->special.arg2 = arg2; entry->special.arg3 = arg3; spin_unlock_irqrestore(&data->lock, irq_flags); - - if (!(trace_flags & TRACE_ITER_BLOCK)) - wake_up(&trace_wait); } +#endif + void __trace_stack(struct trace_array *tr, struct trace_array_cpu *data, unsigned long flags, @@ -739,9 +736,6 @@ tracing_sched_switch_trace(struct trace_array *tr, entry->ctx.next_prio = next->prio; __trace_stack(tr, data, flags, 4); spin_unlock_irqrestore(&data->lock, irq_flags); - - if (!(trace_flags & TRACE_ITER_BLOCK)) - wake_up(&trace_wait); } void @@ -765,9 +759,6 @@ tracing_sched_wakeup_trace(struct trace_array *tr, entry->ctx.next_prio = wakee->prio; __trace_stack(tr, data, flags, 5); spin_unlock_irqrestore(&data->lock, irq_flags); - - if (!(trace_flags & TRACE_ITER_BLOCK)) - wake_up(&trace_wait); } #ifdef CONFIG_FTRACE @@ -1258,7 +1249,7 @@ print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu) comm); break; case TRACE_SPECIAL: - trace_seq_printf(s, " %lx %lx %lx\n", + trace_seq_printf(s, " %ld %ld %ld\n", entry->special.arg1, entry->special.arg2, entry->special.arg3); @@ -1344,7 +1335,7 @@ static int print_trace_fmt(struct trace_iterator *iter) return 0; break; case TRACE_SPECIAL: - ret = trace_seq_printf(s, " %lx %lx %lx\n", + ret = trace_seq_printf(s, " %ld %ld %ld\n", entry->special.arg1, entry->special.arg2, entry->special.arg3); @@ -1409,7 +1400,7 @@ static int print_raw_fmt(struct trace_iterator *iter) break; case TRACE_SPECIAL: case TRACE_STACK: - ret = trace_seq_printf(s, " %lx %lx %lx\n", + ret = trace_seq_printf(s, " %ld %ld %ld\n", entry->special.arg1, entry->special.arg2, entry->special.arg3); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 387bdcf45e2..75e23747567 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -274,4 +274,18 @@ extern int trace_selftest_startup_sched_switch(struct tracer *trace, extern void *head_page(struct trace_array_cpu *data); +extern unsigned long trace_flags; + +enum trace_iterator_flags { + TRACE_ITER_PRINT_PARENT = 0x01, + TRACE_ITER_SYM_OFFSET = 0x02, + TRACE_ITER_SYM_ADDR = 0x04, + TRACE_ITER_VERBOSE = 0x08, + TRACE_ITER_RAW = 0x10, + TRACE_ITER_HEX = 0x20, + TRACE_ITER_BIN = 0x40, + TRACE_ITER_BLOCK = 0x80, + TRACE_ITER_STACKTRACE = 0x100, +}; + #endif /* _LINUX_KERNEL_TRACE_H */ diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index 8b1cf1a3aee..12658b3f2b2 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -18,7 +18,7 @@ static struct trace_array *ctx_trace; static int __read_mostly tracer_enabled; static void -ctx_switch_func(struct task_struct *prev, struct task_struct *next) +ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next) { struct trace_array *tr = ctx_trace; struct trace_array_cpu *data; @@ -34,14 +34,17 @@ ctx_switch_func(struct task_struct *prev, struct task_struct *next) data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); - if (likely(disabled == 1)) + if (likely(disabled == 1)) { tracing_sched_switch_trace(tr, data, prev, next, flags); + ftrace_all_fair_tasks(__rq, tr, data); + } atomic_dec(&data->disabled); local_irq_restore(flags); } -static void wakeup_func(struct task_struct *wakee, struct task_struct *curr) +static void +wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr) { struct trace_array *tr = ctx_trace; struct trace_array_cpu *data; @@ -57,14 +60,18 @@ static void wakeup_func(struct task_struct *wakee, struct task_struct *curr) data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); - if (likely(disabled == 1)) + if (likely(disabled == 1)) { tracing_sched_wakeup_trace(tr, data, wakee, curr, flags); + ftrace_all_fair_tasks(__rq, tr, data); + } atomic_dec(&data->disabled); local_irq_restore(flags); } -void ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next) +void +ftrace_ctx_switch(void *__rq, struct task_struct *prev, + struct task_struct *next) { tracing_record_cmdline(prev); @@ -72,7 +79,7 @@ void ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next) * If tracer_switch_func only points to the local * switch func, it still needs the ptr passed to it. */ - ctx_switch_func(prev, next); + ctx_switch_func(__rq, prev, next); /* * Chain to the wakeup tracer (this is a NOP if disabled): @@ -81,11 +88,12 @@ void ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next) } void -ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr) +ftrace_wake_up_task(void *__rq, struct task_struct *wakee, + struct task_struct *curr) { tracing_record_cmdline(curr); - wakeup_func(wakee, curr); + wakeup_func(__rq, wakee, curr); /* * Chain to the wakeup tracer (this is a NOP if disabled): -- cgit v1.2.3-70-g09d2 From 24cd5d111e8c713e62cda7ca1d01232402e3d3c9 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:20:52 +0200 Subject: ftrace: trace curr/next tasks Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index b9208a0e33a..673b588b713 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2398,8 +2398,8 @@ static int sched_balance_self(int cpu, int flag) void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) { - struct sched_entity *se; struct task_struct *p; + struct sched_entity *se; struct rb_node *curr; struct rq *rq = __rq; @@ -2407,6 +2407,17 @@ void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) if (!curr) return; + if (rq->cfs.curr) { + p = task_of(rq->cfs.curr); + __trace_special(__tr, __data, + p->pid, p->se.vruntime, p->se.sum_exec_runtime); + } + if (rq->cfs.next) { + p = task_of(rq->cfs.next); + __trace_special(__tr, __data, + p->pid, p->se.vruntime, p->se.sum_exec_runtime); + } + while (curr) { se = rb_entry(curr, struct sched_entity, run_node); if (!entity_is_task(se)) -- cgit v1.2.3-70-g09d2 From 017730c11241e26577673eb9d957cfc66172ea91 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:20:52 +0200 Subject: ftrace: fix wakeups Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/sched.h | 2 ++ kernel/sched.c | 18 ++++++++++++++++++ kernel/trace/trace.c | 15 +++++++++++---- 3 files changed, 31 insertions(+), 4 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 652d380ae56..a3970b56375 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -246,6 +246,8 @@ extern asmlinkage void schedule_tail(struct task_struct *prev); extern void init_idle(struct task_struct *idle, int cpu); extern void init_idle_bootup_task(struct task_struct *idle); +extern int runqueue_is_locked(void); + extern cpumask_t nohz_cpu_mask; #if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ) extern int select_nohz_load_balancer(int cpu); diff --git a/kernel/sched.c b/kernel/sched.c index 673b588b713..9ca4a2e6a23 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -642,6 +642,24 @@ static inline void update_rq_clock(struct rq *rq) # define const_debug static const #endif +/** + * runqueue_is_locked + * + * Returns true if the current cpu runqueue is locked. + * This interface allows printk to be called with the runqueue lock + * held and know whether or not it is OK to wake up the klogd. + */ +int runqueue_is_locked(void) +{ + int cpu = get_cpu(); + struct rq *rq = cpu_rq(cpu); + int ret; + + ret = spin_is_locked(&rq->lock); + put_cpu(); + return ret; +} + /* * Debugging: various feature bits */ diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 65173b14b91..2ca9d66aa74 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -70,12 +70,13 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait); unsigned long trace_flags = TRACE_ITER_PRINT_PARENT; -/* - * FIXME: where should this be called? - */ void trace_wake_up(void) { - if (!(trace_flags & TRACE_ITER_BLOCK)) + /* + * The runqueue_is_locked() can fail, but this is the best we + * have for now: + */ + if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked()) wake_up(&trace_wait); } @@ -657,6 +658,8 @@ trace_function(struct trace_array *tr, struct trace_array_cpu *data, entry->fn.ip = ip; entry->fn.parent_ip = parent_ip; spin_unlock_irqrestore(&data->lock, irq_flags); + + trace_wake_up(); } void @@ -686,6 +689,8 @@ __trace_special(void *__tr, void *__data, entry->special.arg2 = arg2; entry->special.arg3 = arg3; spin_unlock_irqrestore(&data->lock, irq_flags); + + trace_wake_up(); } #endif @@ -759,6 +764,8 @@ tracing_sched_wakeup_trace(struct trace_array *tr, entry->ctx.next_prio = wakee->prio; __trace_stack(tr, data, flags, 5); spin_unlock_irqrestore(&data->lock, irq_flags); + + trace_wake_up(); } #ifdef CONFIG_FTRACE -- cgit v1.2.3-70-g09d2 From 36fc25a9f48deacd8aa08cd2d1c186a4e412604f Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:20:53 +0200 Subject: ftrace: sched tree fix Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 9ca4a2e6a23..3bc7c536299 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2414,6 +2414,23 @@ static int sched_balance_self(int cpu, int flag) #ifdef CONFIG_CONTEXT_SWITCH_TRACER +void ftrace_task(struct task_struct *p, void *__tr, void *__data) +{ +#if 0 + /* + * trace timeline tree + */ + __trace_special(__tr, __data, + p->pid, p->se.vruntime, p->se.sum_exec_runtime); +#else + /* + * trace balance metrics + */ + __trace_special(__tr, __data, + p->pid, p->se.avg_overlap, 0); +#endif +} + void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) { struct task_struct *p; @@ -2421,32 +2438,22 @@ void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) struct rb_node *curr; struct rq *rq = __rq; - curr = first_fair(&rq->cfs); - if (!curr) - return; - if (rq->cfs.curr) { p = task_of(rq->cfs.curr); - __trace_special(__tr, __data, - p->pid, p->se.vruntime, p->se.sum_exec_runtime); + ftrace_task(p, __tr, __data); } if (rq->cfs.next) { p = task_of(rq->cfs.next); - __trace_special(__tr, __data, - p->pid, p->se.vruntime, p->se.sum_exec_runtime); + ftrace_task(p, __tr, __data); } - while (curr) { + for (curr = first_fair(&rq->cfs); curr; curr = rb_next(curr)) { se = rb_entry(curr, struct sched_entity, run_node); if (!entity_is_task(se)) continue; p = task_of(se); - - __trace_special(__tr, __data, - p->pid, p->se.vruntime, p->se.sum_exec_runtime); - - curr = rb_next(curr); + ftrace_task(p, __tr, __data); } } -- cgit v1.2.3-70-g09d2 From 5429db2d26a59903c81a4f6c6dae7eb9daaea5fc Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 12 May 2008 21:20:53 +0200 Subject: ftrace: fix wakeup callback Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 3bc7c536299..1ec3fb2efee 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2533,7 +2533,6 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) out_activate: #endif /* CONFIG_SMP */ - ftrace_wake_up_task(rq, p, rq->curr); schedstat_inc(p, se.nr_wakeups); if (sync) schedstat_inc(p, se.nr_wakeups_sync); @@ -2548,6 +2547,7 @@ out_activate: success = 1; out_running: + ftrace_wake_up_task(rq, p, rq->curr); check_preempt_curr(rq, p); p->state = TASK_RUNNING; -- cgit v1.2.3-70-g09d2 From 4d9493c90f8e6e1b164aede3814010a290161abb Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:20:54 +0200 Subject: ftrace: remove add-hoc code Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 47 --------------------------------------- kernel/sched_fair.c | 3 --- kernel/trace/trace_sched_switch.c | 10 ++------- 3 files changed, 2 insertions(+), 58 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 1ec3fb2efee..ad95cca4e42 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2412,53 +2412,6 @@ static int sched_balance_self(int cpu, int flag) #endif /* CONFIG_SMP */ -#ifdef CONFIG_CONTEXT_SWITCH_TRACER - -void ftrace_task(struct task_struct *p, void *__tr, void *__data) -{ -#if 0 - /* - * trace timeline tree - */ - __trace_special(__tr, __data, - p->pid, p->se.vruntime, p->se.sum_exec_runtime); -#else - /* - * trace balance metrics - */ - __trace_special(__tr, __data, - p->pid, p->se.avg_overlap, 0); -#endif -} - -void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) -{ - struct task_struct *p; - struct sched_entity *se; - struct rb_node *curr; - struct rq *rq = __rq; - - if (rq->cfs.curr) { - p = task_of(rq->cfs.curr); - ftrace_task(p, __tr, __data); - } - if (rq->cfs.next) { - p = task_of(rq->cfs.next); - ftrace_task(p, __tr, __data); - } - - for (curr = first_fair(&rq->cfs); curr; curr = rb_next(curr)) { - se = rb_entry(curr, struct sched_entity, run_node); - if (!entity_is_task(se)) - continue; - - p = task_of(se); - ftrace_task(p, __tr, __data); - } -} - -#endif - /*** * try_to_wake_up - wake up a thread * @p: the to-be-woken-up thread diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index dc1856f1079..e24ecd39c4b 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1061,8 +1061,6 @@ wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq, if (!(this_sd->flags & SD_WAKE_AFFINE)) return 0; - ftrace_special(__LINE__, curr->se.avg_overlap, sync); - ftrace_special(__LINE__, p->se.avg_overlap, -1); /* * If the currently running task will sleep within * a reasonable amount of time then attract this newly @@ -1240,7 +1238,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p) if (unlikely(se == pse)) return; - ftrace_special(__LINE__, p->pid, se->last_wakeup); cfs_rq_of(pse)->next = pse; /* diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index bddf676914e..5671db0e182 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -36,11 +36,8 @@ ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next) data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); - if (likely(disabled == 1)) { + if (likely(disabled == 1)) tracing_sched_switch_trace(tr, data, prev, next, flags); - if (trace_flags & TRACE_ITER_SCHED_TREE) - ftrace_all_fair_tasks(__rq, tr, data); - } atomic_dec(&data->disabled); local_irq_restore(flags); @@ -65,11 +62,8 @@ wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr) data = tr->data[cpu]; disabled = atomic_inc_return(&data->disabled); - if (likely(disabled == 1)) { + if (likely(disabled == 1)) tracing_sched_wakeup_trace(tr, data, wakee, curr, flags); - if (trace_flags & TRACE_ITER_SCHED_TREE) - ftrace_all_fair_tasks(__rq, tr, data); - } atomic_dec(&data->disabled); local_irq_restore(flags); -- cgit v1.2.3-70-g09d2 From 5b82a1b08a00b2adca3d9dd9777efff40b7aaaa1 Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Mon, 12 May 2008 21:21:10 +0200 Subject: Port ftrace to markers Porting ftrace to the marker infrastructure. Don't need to chain to the wakeup tracer from the sched tracer, because markers support multiple probes connected. Signed-off-by: Mathieu Desnoyers CC: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/sched.h | 32 ------- kernel/sched.c | 14 +++- kernel/trace/trace.h | 20 +---- kernel/trace/trace_sched_switch.c | 171 +++++++++++++++++++++++++++++++------- kernel/trace/trace_sched_wakeup.c | 106 +++++++++++++++++++++-- 5 files changed, 255 insertions(+), 88 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 360ca99033d..c0b1c69b55c 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2131,38 +2131,6 @@ __trace_special(void *__tr, void *__data, } #endif -#ifdef CONFIG_CONTEXT_SWITCH_TRACER -extern void -ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next); -extern void -ftrace_wake_up_task(void *rq, struct task_struct *wakee, - struct task_struct *curr); -extern void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data); -extern void -ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3); -#else -static inline void -ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next) -{ -} -static inline void -sched_trace_special(unsigned long p1, unsigned long p2, unsigned long p3) -{ -} -static inline void -ftrace_wake_up_task(void *rq, struct task_struct *wakee, - struct task_struct *curr) -{ -} -static inline void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data) -{ -} -static inline void -ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) -{ -} -#endif - extern long sched_setaffinity(pid_t pid, const cpumask_t *new_mask); extern long sched_getaffinity(pid_t pid, cpumask_t *mask); diff --git a/kernel/sched.c b/kernel/sched.c index ad95cca4e42..e2e985eeee7 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2500,7 +2500,9 @@ out_activate: success = 1; out_running: - ftrace_wake_up_task(rq, p, rq->curr); + trace_mark(kernel_sched_wakeup, + "pid %d state %ld ## rq %p task %p rq->curr %p", + p->pid, p->state, rq, p, rq->curr); check_preempt_curr(rq, p); p->state = TASK_RUNNING; @@ -2631,7 +2633,9 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) p->sched_class->task_new(rq, p); inc_nr_running(rq); } - ftrace_wake_up_task(rq, p, rq->curr); + trace_mark(kernel_sched_wakeup_new, + "pid %d state %ld ## rq %p task %p rq->curr %p", + p->pid, p->state, rq, p, rq->curr); check_preempt_curr(rq, p); #ifdef CONFIG_SMP if (p->sched_class->task_wake_up) @@ -2804,7 +2808,11 @@ context_switch(struct rq *rq, struct task_struct *prev, struct mm_struct *mm, *oldmm; prepare_task_switch(rq, prev, next); - ftrace_ctx_switch(rq, prev, next); + trace_mark(kernel_sched_schedule, + "prev_pid %d next_pid %d prev_state %ld " + "## rq %p prev %p next %p", + prev->pid, next->pid, prev->state, + rq, prev, next); mm = next->mm; oldmm = prev->active_mm; /* diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 8845033ab49..f5de0601b40 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -234,25 +234,10 @@ void update_max_tr_single(struct trace_array *tr, extern cycle_t ftrace_now(int cpu); -#ifdef CONFIG_SCHED_TRACER -extern void -wakeup_sched_switch(struct task_struct *prev, struct task_struct *next); -extern void -wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr); -#else -static inline void -wakeup_sched_switch(struct task_struct *prev, struct task_struct *next) -{ -} -static inline void -wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr) -{ -} -#endif - #ifdef CONFIG_CONTEXT_SWITCH_TRACER typedef void (*tracer_switch_func_t)(void *private, + void *__rq, struct task_struct *prev, struct task_struct *next); @@ -262,9 +247,6 @@ struct tracer_switch_ops { struct tracer_switch_ops *next; }; -extern int register_tracer_switch(struct tracer_switch_ops *ops); -extern int unregister_tracer_switch(struct tracer_switch_ops *ops); - #endif /* CONFIG_CONTEXT_SWITCH_TRACER */ #ifdef CONFIG_DYNAMIC_FTRACE diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index a3376478fc2..d25ffa5eaf2 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -16,11 +16,14 @@ static struct trace_array *ctx_trace; static int __read_mostly tracer_enabled; +static atomic_t sched_ref; static void -ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next) +sched_switch_func(void *private, void *__rq, struct task_struct *prev, + struct task_struct *next) { - struct trace_array *tr = ctx_trace; + struct trace_array **ptr = private; + struct trace_array *tr = *ptr; struct trace_array_cpu *data; unsigned long flags; long disabled; @@ -41,10 +44,40 @@ ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next) local_irq_restore(flags); } +static notrace void +sched_switch_callback(void *probe_data, void *call_data, + const char *format, va_list *args) +{ + struct task_struct *prev; + struct task_struct *next; + struct rq *__rq; + + if (!atomic_read(&sched_ref)) + return; + + /* skip prev_pid %d next_pid %d prev_state %ld */ + (void)va_arg(*args, int); + (void)va_arg(*args, int); + (void)va_arg(*args, long); + __rq = va_arg(*args, typeof(__rq)); + prev = va_arg(*args, typeof(prev)); + next = va_arg(*args, typeof(next)); + + tracing_record_cmdline(prev); + + /* + * If tracer_switch_func only points to the local + * switch func, it still needs the ptr passed to it. + */ + sched_switch_func(probe_data, __rq, prev, next); +} + static void -wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr) +wakeup_func(void *private, void *__rq, struct task_struct *wakee, struct + task_struct *curr) { - struct trace_array *tr = ctx_trace; + struct trace_array **ptr = private; + struct trace_array *tr = *ptr; struct trace_array_cpu *data; unsigned long flags; long disabled; @@ -67,35 +100,29 @@ wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr) local_irq_restore(flags); } -void -ftrace_ctx_switch(void *__rq, struct task_struct *prev, - struct task_struct *next) +static notrace void +wake_up_callback(void *probe_data, void *call_data, + const char *format, va_list *args) { - if (unlikely(atomic_read(&trace_record_cmdline_enabled))) - tracing_record_cmdline(prev); + struct task_struct *curr; + struct task_struct *task; + struct rq *__rq; - /* - * If tracer_switch_func only points to the local - * switch func, it still needs the ptr passed to it. - */ - ctx_switch_func(__rq, prev, next); + if (likely(!tracer_enabled)) + return; - /* - * Chain to the wakeup tracer (this is a NOP if disabled): - */ - wakeup_sched_switch(prev, next); -} + /* Skip pid %d state %ld */ + (void)va_arg(*args, int); + (void)va_arg(*args, long); + /* now get the meat: "rq %p task %p rq->curr %p" */ + __rq = va_arg(*args, typeof(__rq)); + task = va_arg(*args, typeof(task)); + curr = va_arg(*args, typeof(curr)); -void -ftrace_wake_up_task(void *__rq, struct task_struct *wakee, - struct task_struct *curr) -{ - wakeup_func(__rq, wakee, curr); + tracing_record_cmdline(task); + tracing_record_cmdline(curr); - /* - * Chain to the wakeup tracer (this is a NOP if disabled): - */ - wakeup_sched_wakeup(wakee, curr); + wakeup_func(probe_data, __rq, task, curr); } void @@ -132,15 +159,95 @@ static void sched_switch_reset(struct trace_array *tr) tracing_reset(tr->data[cpu]); } +static int tracing_sched_register(void) +{ + int ret; + + ret = marker_probe_register("kernel_sched_wakeup", + "pid %d state %ld ## rq %p task %p rq->curr %p", + wake_up_callback, + &ctx_trace); + if (ret) { + pr_info("wakeup trace: Couldn't add marker" + " probe to kernel_sched_wakeup\n"); + return ret; + } + + ret = marker_probe_register("kernel_sched_wakeup_new", + "pid %d state %ld ## rq %p task %p rq->curr %p", + wake_up_callback, + &ctx_trace); + if (ret) { + pr_info("wakeup trace: Couldn't add marker" + " probe to kernel_sched_wakeup_new\n"); + goto fail_deprobe; + } + + ret = marker_probe_register("kernel_sched_schedule", + "prev_pid %d next_pid %d prev_state %ld " + "## rq %p prev %p next %p", + sched_switch_callback, + &ctx_trace); + if (ret) { + pr_info("sched trace: Couldn't add marker" + " probe to kernel_sched_schedule\n"); + goto fail_deprobe_wake_new; + } + + return ret; +fail_deprobe_wake_new: + marker_probe_unregister("kernel_sched_wakeup_new", + wake_up_callback, + &ctx_trace); +fail_deprobe: + marker_probe_unregister("kernel_sched_wakeup", + wake_up_callback, + &ctx_trace); + return ret; +} + +static void tracing_sched_unregister(void) +{ + marker_probe_unregister("kernel_sched_schedule", + sched_switch_callback, + &ctx_trace); + marker_probe_unregister("kernel_sched_wakeup_new", + wake_up_callback, + &ctx_trace); + marker_probe_unregister("kernel_sched_wakeup", + wake_up_callback, + &ctx_trace); +} + +void tracing_start_sched_switch(void) +{ + long ref; + + ref = atomic_inc_return(&sched_ref); + if (ref == 1) + tracing_sched_register(); +} + +void tracing_stop_sched_switch(void) +{ + long ref; + + ref = atomic_dec_and_test(&sched_ref); + if (ref) + tracing_sched_unregister(); +} + static void start_sched_trace(struct trace_array *tr) { sched_switch_reset(tr); atomic_inc(&trace_record_cmdline_enabled); tracer_enabled = 1; + tracing_start_sched_switch(); } static void stop_sched_trace(struct trace_array *tr) { + tracing_stop_sched_switch(); atomic_dec(&trace_record_cmdline_enabled); tracer_enabled = 0; } @@ -181,6 +288,14 @@ static struct tracer sched_switch_trace __read_mostly = __init static int init_sched_switch_trace(void) { + int ret = 0; + + if (atomic_read(&sched_ref)) + ret = tracing_sched_register(); + if (ret) { + pr_info("error registering scheduler trace\n"); + return ret; + } return register_tracer(&sched_switch_trace); } device_initcall(init_sched_switch_trace); diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 5948011006b..5d2fb48e47f 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -15,6 +15,7 @@ #include #include #include +#include #include "trace.h" @@ -44,11 +45,13 @@ static int report_latency(cycle_t delta) return 1; } -void -wakeup_sched_switch(struct task_struct *prev, struct task_struct *next) +static void notrace +wakeup_sched_switch(void *private, void *rq, struct task_struct *prev, + struct task_struct *next) { unsigned long latency = 0, t0 = 0, t1 = 0; - struct trace_array *tr = wakeup_trace; + struct trace_array **ptr = private; + struct trace_array *tr = *ptr; struct trace_array_cpu *data; cycle_t T0, T1, delta; unsigned long flags; @@ -113,6 +116,31 @@ out: atomic_dec(&tr->data[cpu]->disabled); } +static notrace void +sched_switch_callback(void *probe_data, void *call_data, + const char *format, va_list *args) +{ + struct task_struct *prev; + struct task_struct *next; + struct rq *__rq; + + /* skip prev_pid %d next_pid %d prev_state %ld */ + (void)va_arg(*args, int); + (void)va_arg(*args, int); + (void)va_arg(*args, long); + __rq = va_arg(*args, typeof(__rq)); + prev = va_arg(*args, typeof(prev)); + next = va_arg(*args, typeof(next)); + + tracing_record_cmdline(prev); + + /* + * If tracer_switch_func only points to the local + * switch func, it still needs the ptr passed to it. + */ + wakeup_sched_switch(probe_data, __rq, prev, next); +} + static void __wakeup_reset(struct trace_array *tr) { struct trace_array_cpu *data; @@ -188,19 +216,68 @@ out: atomic_dec(&tr->data[cpu]->disabled); } -void wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr) +static notrace void +wake_up_callback(void *probe_data, void *call_data, + const char *format, va_list *args) { + struct trace_array **ptr = probe_data; + struct trace_array *tr = *ptr; + struct task_struct *curr; + struct task_struct *task; + struct rq *__rq; + if (likely(!tracer_enabled)) return; + /* Skip pid %d state %ld */ + (void)va_arg(*args, int); + (void)va_arg(*args, long); + /* now get the meat: "rq %p task %p rq->curr %p" */ + __rq = va_arg(*args, typeof(__rq)); + task = va_arg(*args, typeof(task)); + curr = va_arg(*args, typeof(curr)); + + tracing_record_cmdline(task); tracing_record_cmdline(curr); - tracing_record_cmdline(wakee); - wakeup_check_start(wakeup_trace, wakee, curr); + wakeup_check_start(tr, task, curr); } static void start_wakeup_tracer(struct trace_array *tr) { + int ret; + + ret = marker_probe_register("kernel_sched_wakeup", + "pid %d state %ld ## rq %p task %p rq->curr %p", + wake_up_callback, + &wakeup_trace); + if (ret) { + pr_info("wakeup trace: Couldn't add marker" + " probe to kernel_sched_wakeup\n"); + return; + } + + ret = marker_probe_register("kernel_sched_wakeup_new", + "pid %d state %ld ## rq %p task %p rq->curr %p", + wake_up_callback, + &wakeup_trace); + if (ret) { + pr_info("wakeup trace: Couldn't add marker" + " probe to kernel_sched_wakeup_new\n"); + goto fail_deprobe; + } + + ret = marker_probe_register("kernel_sched_schedule", + "prev_pid %d next_pid %d prev_state %ld " + "## rq %p prev %p next %p", + sched_switch_callback, + &wakeup_trace); + if (ret) { + pr_info("sched trace: Couldn't add marker" + " probe to kernel_sched_schedule\n"); + goto fail_deprobe_wake_new; + } + wakeup_reset(tr); /* @@ -215,11 +292,28 @@ static void start_wakeup_tracer(struct trace_array *tr) tracer_enabled = 1; return; +fail_deprobe_wake_new: + marker_probe_unregister("kernel_sched_wakeup_new", + wake_up_callback, + &wakeup_trace); +fail_deprobe: + marker_probe_unregister("kernel_sched_wakeup", + wake_up_callback, + &wakeup_trace); } static void stop_wakeup_tracer(struct trace_array *tr) { tracer_enabled = 0; + marker_probe_unregister("kernel_sched_schedule", + sched_switch_callback, + &wakeup_trace); + marker_probe_unregister("kernel_sched_wakeup_new", + wake_up_callback, + &wakeup_trace); + marker_probe_unregister("kernel_sched_wakeup", + wake_up_callback, + &wakeup_trace); } static void wakeup_tracer_init(struct trace_array *tr) -- cgit v1.2.3-70-g09d2 From 962cf36c5bf6d2840b8d66ee9a606fae2f540bbd Mon Sep 17 00:00:00 2001 From: "Carlos R. Mafra" Date: Thu, 15 May 2008 11:15:37 -0300 Subject: Remove argument from open_softirq which is always NULL As git-grep shows, open_softirq() is always called with the last argument being NULL block/blk-core.c: open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL); kernel/hrtimer.c: open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL); kernel/rcuclassic.c: open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); kernel/rcupreempt.c: open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); kernel/sched.c: open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); kernel/softirq.c: open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL); kernel/softirq.c: open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL); kernel/timer.c: open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); net/core/dev.c: open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL); net/core/dev.c: open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL); This observation has already been made by Matthew Wilcox in June 2002 (http://www.cs.helsinki.fi/linux/linux-kernel/2002-25/0687.html) "I notice that none of the current softirq routines use the data element passed to them." and the situation hasn't changed since them. So it appears we can safely remove that extra argument to save 128 (54) bytes of kernel data (text). Signed-off-by: Carlos R. Mafra Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- block/blk-core.c | 2 +- include/linux/interrupt.h | 3 +-- kernel/hrtimer.c | 2 +- kernel/rcuclassic.c | 2 +- kernel/rcupreempt.c | 2 +- kernel/sched.c | 2 +- kernel/softirq.c | 7 +++---- kernel/timer.c | 2 +- net/core/dev.c | 4 ++-- 9 files changed, 12 insertions(+), 14 deletions(-) (limited to 'kernel/sched.c') diff --git a/block/blk-core.c b/block/blk-core.c index 6a9cc0d22a6..75fdc65136e 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2048,7 +2048,7 @@ int __init blk_dev_init(void) for_each_possible_cpu(i) INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i)); - open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL); + open_softirq(BLOCK_SOFTIRQ, blk_done_softirq); register_hotcpu_notifier(&blk_cpu_notifier); return 0; diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index f1fc7470d26..a86186dd047 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -285,12 +285,11 @@ enum struct softirq_action { void (*action)(struct softirq_action *); - void *data; }; asmlinkage void do_softirq(void); asmlinkage void __do_softirq(void); -extern void open_softirq(int nr, void (*action)(struct softirq_action*), void *data); +extern void open_softirq(int nr, void (*action)(struct softirq_action *)); extern void softirq_init(void); #define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0) extern void raise_softirq_irqoff(unsigned int nr); diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 421be5fe5cc..861b4088092 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -1669,7 +1669,7 @@ void __init hrtimers_init(void) (void *)(long)smp_processor_id()); register_cpu_notifier(&hrtimers_nb); #ifdef CONFIG_HIGH_RES_TIMERS - open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL); + open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq); #endif } diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c index f4ffbd0f306..f6e01f3ae9c 100644 --- a/kernel/rcuclassic.c +++ b/kernel/rcuclassic.c @@ -529,7 +529,7 @@ static void __cpuinit rcu_online_cpu(int cpu) rcu_init_percpu_data(cpu, &rcu_ctrlblk, rdp); rcu_init_percpu_data(cpu, &rcu_bh_ctrlblk, bh_rdp); - open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); + open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); } static int __cpuinit rcu_cpu_notify(struct notifier_block *self, diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c index e1cdf196a51..9dd827db359 100644 --- a/kernel/rcupreempt.c +++ b/kernel/rcupreempt.c @@ -1125,7 +1125,7 @@ void __init __rcu_init(void) for_each_online_cpu(cpu) rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long) cpu); - open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); + open_softirq(RCU_SOFTIRQ, rcu_process_callbacks); } /* diff --git a/kernel/sched.c b/kernel/sched.c index cfa222a9153..56ea3a203a5 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8154,7 +8154,7 @@ void __init sched_init(void) #endif #ifdef CONFIG_SMP - open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); + open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); #endif #ifdef CONFIG_RT_MUTEXES diff --git a/kernel/softirq.c b/kernel/softirq.c index 36e06174004..059256874e9 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -347,9 +347,8 @@ void raise_softirq(unsigned int nr) local_irq_restore(flags); } -void open_softirq(int nr, void (*action)(struct softirq_action*), void *data) +void open_softirq(int nr, void (*action)(struct softirq_action *)) { - softirq_vec[nr].data = data; softirq_vec[nr].action = action; } @@ -503,8 +502,8 @@ void __init softirq_init(void) &per_cpu(tasklet_hi_vec, cpu).head; } - open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL); - open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL); + open_softirq(TASKLET_SOFTIRQ, tasklet_action); + open_softirq(HI_SOFTIRQ, tasklet_hi_action); } static int ksoftirqd(void * __bind_cpu) diff --git a/kernel/timer.c b/kernel/timer.c index ceacc662657..b4da888497f 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1502,7 +1502,7 @@ void __init init_timers(void) BUG_ON(err == NOTIFY_BAD); register_cpu_notifier(&timers_nb); - open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL); + open_softirq(TIMER_SOFTIRQ, run_timer_softirq); } /** diff --git a/net/core/dev.c b/net/core/dev.c index 58296307787..cf0e16731dc 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4563,8 +4563,8 @@ static int __init net_dev_init(void) dev_boot_phase = 0; - open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL); - open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL); + open_softirq(NET_TX_SOFTIRQ, net_tx_action); + open_softirq(NET_RX_SOFTIRQ, net_rx_action); hotcpu_notifier(dev_cpu_callback, 0); dst_init(); -- cgit v1.2.3-70-g09d2 From c6531cce6e6e4b99bcda46b6268d6f2d9e30aea4 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 12 May 2008 21:21:14 +0200 Subject: sched: do not trace sched_clock The tracer uses sched_clock, so do not trace it. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index e2e985eeee7..6590a828138 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -884,12 +884,12 @@ static unsigned long long __cpu_clock(int cpu) * For kernel-internal use: high-speed (but slightly incorrect) per-cpu * clock constructed from sched_clock(): */ -unsigned long long cpu_clock(int cpu) +unsigned long long notrace cpu_clock(int cpu) { unsigned long long prev_cpu_time, time, delta_time; unsigned long flags; - local_irq_save(flags); + raw_local_irq_save(flags); prev_cpu_time = per_cpu(prev_cpu_time, cpu); time = __cpu_clock(cpu) + per_cpu(time_offset, cpu); delta_time = time-prev_cpu_time; @@ -898,7 +898,7 @@ unsigned long long cpu_clock(int cpu) time = __sync_cpu_clock(time, cpu); per_cpu(prev_cpu_time, cpu) = time; } - local_irq_restore(flags); + raw_local_irq_restore(flags); return time; } -- cgit v1.2.3-70-g09d2 From 45c01e824991b2dd0a332e19efc4901acb31209f Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Mon, 12 May 2008 21:20:41 +0200 Subject: sched: prioritize non-migratable tasks over migratable ones Dmitry Adamushko pointed out a known flaw in the rt-balancing algorithm that could allow suboptimal balancing if a non-migratable task gets queued behind a running migratable one. It is discussed in this thread: http://lkml.org/lkml/2008/4/22/296 This issue has been further exacerbated by a recent checkin to sched-devel (git-id 5eee63a5ebc19a870ac40055c0be49457f3a89a3). >From a pure priority standpoint, the run-queue is doing the "right" thing. Using Dmitry's nomenclature, if T0 is on cpu1 first, and T1 wakes up at equal or lower priority (affined only to cpu1) later, it *should* wait for T0 to finish. However, in reality that is likely suboptimal from a system perspective if there are other cores that could allow T0 and T1 to run concurrently. Since T1 can not migrate, the only choice for higher concurrency is to try to move T0. This is not something we addessed in the recent rt-balancing re-work. This patch tries to enhance the balancing algorithm by accomodating this scenario. It accomplishes this by incorporating the migratability of a task into its priority calculation. Within a numerical tsk->prio, a non-migratable task is logically higher than a migratable one. We maintain this by introducing a new per-priority queue (xqueue, or exclusive-queue) for holding non-migratable tasks. The scheduler will draw from the xqueue over the standard shared-queue (squeue) when available. There are several details for utilizing this properly. 1) During task-wake-up, we not only need to check if the priority preempts the current task, but we also need to check for this non-migratable condition. Therefore, if a non-migratable task wakes up and sees an equal priority migratable task already running, it will attempt to preempt it *if* there is a likelyhood that the current task will find an immediate home. 2) Tasks only get this non-migratable "priority boost" on wake-up. Any requeuing will result in the non-migratable task being queued to the end of the shared queue. This is an attempt to prevent the system from being completely unfair to migratable tasks during things like SCHED_RR timeslicing. I am sure this patch introduces potentially "odd" behavior if you concoct a scenario where a bunch of non-migratable threads could starve migratable ones given the right pattern. I am not yet convinced that this is a problem since we are talking about tasks of equal RT priority anyway, and there never is much in the way of guarantees against starvation under that scenario anyway. (e.g. you could come up with a similar scenario with a specific timing environment verses an affinity environment). I can be convinced otherwise, but for now I think this is "ok". Signed-off-by: Gregory Haskins CC: Dmitry Adamushko CC: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 6 +++-- kernel/sched_rt.c | 75 +++++++++++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 72 insertions(+), 9 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index bfb8ad8ed17..7178b8c2351 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -151,7 +151,8 @@ static inline int task_has_rt_policy(struct task_struct *p) */ struct rt_prio_array { DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ - struct list_head queue[MAX_RT_PRIO]; + struct list_head xqueue[MAX_RT_PRIO]; /* exclusive queue */ + struct list_head squeue[MAX_RT_PRIO]; /* shared queue */ }; struct rt_bandwidth { @@ -7542,7 +7543,8 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) array = &rt_rq->active; for (i = 0; i < MAX_RT_PRIO; i++) { - INIT_LIST_HEAD(array->queue + i); + INIT_LIST_HEAD(array->xqueue + i); + INIT_LIST_HEAD(array->squeue + i); __clear_bit(i, array->bitmap); } /* delimiter for bitsearch: */ diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 3432d573205..fefed39fafd 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -458,7 +458,13 @@ static void enqueue_rt_entity(struct sched_rt_entity *rt_se) if (group_rq && rt_rq_throttled(group_rq)) return; - list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); + if (rt_se->nr_cpus_allowed == 1) + list_add_tail(&rt_se->run_list, + array->xqueue + rt_se_prio(rt_se)); + else + list_add_tail(&rt_se->run_list, + array->squeue + rt_se_prio(rt_se)); + __set_bit(rt_se_prio(rt_se), array->bitmap); inc_rt_tasks(rt_se, rt_rq); @@ -470,7 +476,8 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se) struct rt_prio_array *array = &rt_rq->active; list_del_init(&rt_se->run_list); - if (list_empty(array->queue + rt_se_prio(rt_se))) + if (list_empty(array->squeue + rt_se_prio(rt_se)) + && list_empty(array->xqueue + rt_se_prio(rt_se))) __clear_bit(rt_se_prio(rt_se), array->bitmap); dec_rt_tasks(rt_se, rt_rq); @@ -537,13 +544,19 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) /* * Put task to the end of the run list without the overhead of dequeue * followed by enqueue. + * + * Note: We always enqueue the task to the shared-queue, regardless of its + * previous position w.r.t. exclusive vs shared. This is so that exclusive RR + * tasks fairly round-robin with all tasks on the runqueue, not just other + * exclusive tasks. */ static void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) { struct rt_prio_array *array = &rt_rq->active; - list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); + list_del_init(&rt_se->run_list); + list_add_tail(&rt_se->run_list, array->squeue + rt_se_prio(rt_se)); } static void requeue_task_rt(struct rq *rq, struct task_struct *p) @@ -601,13 +614,46 @@ static int select_task_rq_rt(struct task_struct *p, int sync) } #endif /* CONFIG_SMP */ +static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, + struct rt_rq *rt_rq); + /* * Preempt the current task with a newly woken task if needed: */ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p) { - if (p->prio < rq->curr->prio) + if (p->prio < rq->curr->prio) { resched_task(rq->curr); + return; + } + +#ifdef CONFIG_SMP + /* + * If: + * + * - the newly woken task is of equal priority to the current task + * - the newly woken task is non-migratable while current is migratable + * - current will be preempted on the next reschedule + * + * we should check to see if current can readily move to a different + * cpu. If so, we will reschedule to allow the push logic to try + * to move current somewhere else, making room for our non-migratable + * task. + */ + if((p->prio == rq->curr->prio) + && p->rt.nr_cpus_allowed == 1 + && rq->curr->rt.nr_cpus_allowed != 1 + && pick_next_rt_entity(rq, &rq->rt) != &rq->curr->rt) { + cpumask_t mask; + + if (cpupri_find(&rq->rd->cpupri, rq->curr, &mask)) + /* + * There appears to be other cpus that can accept + * current, so lets reschedule to try and push it away + */ + resched_task(rq->curr); + } +#endif } static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, @@ -621,8 +667,15 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, idx = sched_find_first_bit(array->bitmap); BUG_ON(idx >= MAX_RT_PRIO); - queue = array->queue + idx; - next = list_entry(queue->next, struct sched_rt_entity, run_list); + queue = array->xqueue + idx; + if (!list_empty(queue)) + next = list_entry(queue->next, struct sched_rt_entity, + run_list); + else { + queue = array->squeue + idx; + next = list_entry(queue->next, struct sched_rt_entity, + run_list); + } return next; } @@ -692,7 +745,7 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu) continue; if (next && next->prio < idx) continue; - list_for_each_entry(rt_se, array->queue + idx, run_list) { + list_for_each_entry(rt_se, array->squeue + idx, run_list) { struct task_struct *p = rt_task_of(rt_se); if (pick_rt_task(rq, p, cpu)) { next = p; @@ -1146,6 +1199,14 @@ static void set_cpus_allowed_rt(struct task_struct *p, } update_rt_migration(rq); + + if (unlikely(weight == 1 || p->rt.nr_cpus_allowed == 1)) + /* + * If either the new or old weight is a "1", we need + * to requeue to properly move between shared and + * exclusive queues. + */ + requeue_task_rt(rq, p); } p->cpus_allowed = *new_mask; -- cgit v1.2.3-70-g09d2 From f333fdc9098b71e2687e4e9b6349fcb352960d66 Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Mon, 12 May 2008 21:20:55 +0200 Subject: sched: make !hrtick faster it is safe to ignore timers and flags when the feature is disabled. Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 7178b8c2351..aa960b84b88 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4134,7 +4134,7 @@ asmlinkage void __sched schedule(void) struct task_struct *prev, *next; unsigned long *switch_count; struct rq *rq; - int cpu; + int cpu, hrtick = sched_feat(HRTICK); need_resched: preempt_disable(); @@ -4149,7 +4149,8 @@ need_resched_nonpreemptible: schedule_debug(prev); - hrtick_clear(rq); + if (hrtick) + hrtick_clear(rq); /* * Do the rq-clock update outside the rq lock: @@ -4197,7 +4198,8 @@ need_resched_nonpreemptible: } else spin_unlock_irq(&rq->lock); - hrtick_set(rq); + if (hrtick) + hrtick_set(rq); if (unlikely(reacquire_kernel_lock(current) < 0)) goto need_resched_nonpreemptible; -- cgit v1.2.3-70-g09d2 From 6e0534f278199f1e3dd1049b9bc19a7a5b87ada1 Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Mon, 12 May 2008 21:21:01 +0200 Subject: sched: use a 2-d bitmap for searching lowest-pri CPU The current code use a linear algorithm which causes scaling issues on larger SMP machines. This patch replaces that algorithm with a 2-dimensional bitmap to reduce latencies in the wake-up path. Signed-off-by: Gregory Haskins Acked-by: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/Makefile | 1 + kernel/sched.c | 7 ++ kernel/sched_cpupri.c | 174 ++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/sched_cpupri.h | 36 +++++++++++ kernel/sched_rt.c | 98 ++++++---------------------- 5 files changed, 239 insertions(+), 77 deletions(-) create mode 100644 kernel/sched_cpupri.c create mode 100644 kernel/sched_cpupri.h (limited to 'kernel/sched.c') diff --git a/kernel/Makefile b/kernel/Makefile index 1c9938addb9..ecdd2d33563 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -69,6 +69,7 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o obj-$(CONFIG_MARKERS) += marker.o obj-$(CONFIG_LATENCYTOP) += latencytop.o +obj-$(CONFIG_SMP) += sched_cpupri.o ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y) # According to Alan Modra , the -fno-omit-frame-pointer is diff --git a/kernel/sched.c b/kernel/sched.c index aa960b84b88..8a1257b6556 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -74,6 +74,8 @@ #include #include +#include "sched_cpupri.h" + /* * Convert user-nice values [ -20 ... 0 ... 19 ] * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], @@ -450,6 +452,9 @@ struct root_domain { */ cpumask_t rto_mask; atomic_t rto_count; +#ifdef CONFIG_SMP + struct cpupri cpupri; +#endif }; /* @@ -6392,6 +6397,8 @@ static void init_rootdomain(struct root_domain *rd) cpus_clear(rd->span); cpus_clear(rd->online); + + cpupri_init(&rd->cpupri); } static void init_defrootdomain(void) diff --git a/kernel/sched_cpupri.c b/kernel/sched_cpupri.c new file mode 100644 index 00000000000..52154fefab7 --- /dev/null +++ b/kernel/sched_cpupri.c @@ -0,0 +1,174 @@ +/* + * kernel/sched_cpupri.c + * + * CPU priority management + * + * Copyright (C) 2007-2008 Novell + * + * Author: Gregory Haskins + * + * This code tracks the priority of each CPU so that global migration + * decisions are easy to calculate. Each CPU can be in a state as follows: + * + * (INVALID), IDLE, NORMAL, RT1, ... RT99 + * + * going from the lowest priority to the highest. CPUs in the INVALID state + * are not eligible for routing. The system maintains this state with + * a 2 dimensional bitmap (the first for priority class, the second for cpus + * in that class). Therefore a typical application without affinity + * restrictions can find a suitable CPU with O(1) complexity (e.g. two bit + * searches). For tasks with affinity restrictions, the algorithm has a + * worst case complexity of O(min(102, nr_domcpus)), though the scenario that + * yields the worst case search is fairly contrived. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ + +#include "sched_cpupri.h" + +/* Convert between a 140 based task->prio, and our 102 based cpupri */ +static int convert_prio(int prio) +{ + int cpupri; + + if (prio == CPUPRI_INVALID) + cpupri = CPUPRI_INVALID; + else if (prio == MAX_PRIO) + cpupri = CPUPRI_IDLE; + else if (prio >= MAX_RT_PRIO) + cpupri = CPUPRI_NORMAL; + else + cpupri = MAX_RT_PRIO - prio + 1; + + return cpupri; +} + +#define for_each_cpupri_active(array, idx) \ + for (idx = find_first_bit(array, CPUPRI_NR_PRIORITIES); \ + idx < CPUPRI_NR_PRIORITIES; \ + idx = find_next_bit(array, CPUPRI_NR_PRIORITIES, idx+1)) + +/** + * cpupri_find - find the best (lowest-pri) CPU in the system + * @cp: The cpupri context + * @p: The task + * @lowest_mask: A mask to fill in with selected CPUs + * + * Note: This function returns the recommended CPUs as calculated during the + * current invokation. By the time the call returns, the CPUs may have in + * fact changed priorities any number of times. While not ideal, it is not + * an issue of correctness since the normal rebalancer logic will correct + * any discrepancies created by racing against the uncertainty of the current + * priority configuration. + * + * Returns: (int)bool - CPUs were found + */ +int cpupri_find(struct cpupri *cp, struct task_struct *p, + cpumask_t *lowest_mask) +{ + int idx = 0; + int task_pri = convert_prio(p->prio); + + for_each_cpupri_active(cp->pri_active, idx) { + struct cpupri_vec *vec = &cp->pri_to_cpu[idx]; + cpumask_t mask; + + if (idx >= task_pri) + break; + + cpus_and(mask, p->cpus_allowed, vec->mask); + + if (cpus_empty(mask)) + continue; + + *lowest_mask = mask; + return 1; + } + + return 0; +} + +/** + * cpupri_set - update the cpu priority setting + * @cp: The cpupri context + * @cpu: The target cpu + * @pri: The priority (INVALID-RT99) to assign to this CPU + * + * Note: Assumes cpu_rq(cpu)->lock is locked + * + * Returns: (void) + */ +void cpupri_set(struct cpupri *cp, int cpu, int newpri) +{ + int *currpri = &cp->cpu_to_pri[cpu]; + int oldpri = *currpri; + unsigned long flags; + + newpri = convert_prio(newpri); + + BUG_ON(newpri >= CPUPRI_NR_PRIORITIES); + + if (newpri == oldpri) + return; + + /* + * If the cpu was currently mapped to a different value, we + * first need to unmap the old value + */ + if (likely(oldpri != CPUPRI_INVALID)) { + struct cpupri_vec *vec = &cp->pri_to_cpu[oldpri]; + + spin_lock_irqsave(&vec->lock, flags); + + vec->count--; + if (!vec->count) + clear_bit(oldpri, cp->pri_active); + cpu_clear(cpu, vec->mask); + + spin_unlock_irqrestore(&vec->lock, flags); + } + + if (likely(newpri != CPUPRI_INVALID)) { + struct cpupri_vec *vec = &cp->pri_to_cpu[newpri]; + + spin_lock_irqsave(&vec->lock, flags); + + cpu_set(cpu, vec->mask); + vec->count++; + if (vec->count == 1) + set_bit(newpri, cp->pri_active); + + spin_unlock_irqrestore(&vec->lock, flags); + } + + *currpri = newpri; +} + +/** + * cpupri_init - initialize the cpupri structure + * @cp: The cpupri context + * + * Returns: (void) + */ +void cpupri_init(struct cpupri *cp) +{ + int i; + + memset(cp, 0, sizeof(*cp)); + + for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) { + struct cpupri_vec *vec = &cp->pri_to_cpu[i]; + + spin_lock_init(&vec->lock); + vec->count = 0; + cpus_clear(vec->mask); + } + + for_each_possible_cpu(i) + cp->cpu_to_pri[i] = CPUPRI_INVALID; +} + + diff --git a/kernel/sched_cpupri.h b/kernel/sched_cpupri.h new file mode 100644 index 00000000000..0b6a3d110fa --- /dev/null +++ b/kernel/sched_cpupri.h @@ -0,0 +1,36 @@ +#ifndef _LINUX_CPUPRI_H +#define _LINUX_CPUPRI_H + +#include + +#define CPUPRI_NR_PRIORITIES 2+MAX_RT_PRIO +#define CPUPRI_NR_PRI_WORDS CPUPRI_NR_PRIORITIES/BITS_PER_LONG + +#define CPUPRI_INVALID -1 +#define CPUPRI_IDLE 0 +#define CPUPRI_NORMAL 1 +/* values 2-101 are RT priorities 0-99 */ + +struct cpupri_vec { + spinlock_t lock; + int count; + cpumask_t mask; +}; + +struct cpupri { + struct cpupri_vec pri_to_cpu[CPUPRI_NR_PRIORITIES]; + long pri_active[CPUPRI_NR_PRI_WORDS]; + int cpu_to_pri[NR_CPUS]; +}; + +#ifdef CONFIG_SMP +int cpupri_find(struct cpupri *cp, + struct task_struct *p, cpumask_t *lowest_mask); +void cpupri_set(struct cpupri *cp, int cpu, int pri); +void cpupri_init(struct cpupri *cp); +#else +#define cpupri_set(cp, cpu, pri) do { } while (0) +#define cpupri_init() do { } while (0) +#endif + +#endif /* _LINUX_CPUPRI_H */ diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index fefed39fafd..44b06d75416 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -391,8 +391,11 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) WARN_ON(!rt_prio(rt_se_prio(rt_se))); rt_rq->rt_nr_running++; #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED - if (rt_se_prio(rt_se) < rt_rq->highest_prio) + if (rt_se_prio(rt_se) < rt_rq->highest_prio) { + struct rq *rq = rq_of_rt_rq(rt_rq); rt_rq->highest_prio = rt_se_prio(rt_se); + cpupri_set(&rq->rd->cpupri, rq->cpu, rt_se_prio(rt_se)); + } #endif #ifdef CONFIG_SMP if (rt_se->nr_cpus_allowed > 1) { @@ -416,6 +419,10 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) static inline void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { +#ifdef CONFIG_SMP + int highest_prio = rt_rq->highest_prio; +#endif + WARN_ON(!rt_prio(rt_se_prio(rt_se))); WARN_ON(!rt_rq->rt_nr_running); rt_rq->rt_nr_running--; @@ -439,6 +446,11 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) rq->rt.rt_nr_migratory--; } + if (rt_rq->highest_prio != highest_prio) { + struct rq *rq = rq_of_rt_rq(rt_rq); + cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio); + } + update_rt_migration(rq_of_rt_rq(rt_rq)); #endif /* CONFIG_SMP */ #ifdef CONFIG_RT_GROUP_SCHED @@ -763,73 +775,6 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu) static DEFINE_PER_CPU(cpumask_t, local_cpu_mask); -static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask) -{ - int lowest_prio = -1; - int lowest_cpu = -1; - int count = 0; - int cpu; - - cpus_and(*lowest_mask, task_rq(task)->rd->online, task->cpus_allowed); - - /* - * Scan each rq for the lowest prio. - */ - for_each_cpu_mask(cpu, *lowest_mask) { - struct rq *rq = cpu_rq(cpu); - - /* We look for lowest RT prio or non-rt CPU */ - if (rq->rt.highest_prio >= MAX_RT_PRIO) { - /* - * if we already found a low RT queue - * and now we found this non-rt queue - * clear the mask and set our bit. - * Otherwise just return the queue as is - * and the count==1 will cause the algorithm - * to use the first bit found. - */ - if (lowest_cpu != -1) { - cpus_clear(*lowest_mask); - cpu_set(rq->cpu, *lowest_mask); - } - return 1; - } - - /* no locking for now */ - if ((rq->rt.highest_prio > task->prio) - && (rq->rt.highest_prio >= lowest_prio)) { - if (rq->rt.highest_prio > lowest_prio) { - /* new low - clear old data */ - lowest_prio = rq->rt.highest_prio; - lowest_cpu = cpu; - count = 0; - } - count++; - } else - cpu_clear(cpu, *lowest_mask); - } - - /* - * Clear out all the set bits that represent - * runqueues that were of higher prio than - * the lowest_prio. - */ - if (lowest_cpu > 0) { - /* - * Perhaps we could add another cpumask op to - * zero out bits. Like cpu_zero_bits(cpumask, nrbits); - * Then that could be optimized to use memset and such. - */ - for_each_cpu_mask(cpu, *lowest_mask) { - if (cpu >= lowest_cpu) - break; - cpu_clear(cpu, *lowest_mask); - } - } - - return count; -} - static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask) { int first; @@ -851,17 +796,12 @@ static int find_lowest_rq(struct task_struct *task) cpumask_t *lowest_mask = &__get_cpu_var(local_cpu_mask); int this_cpu = smp_processor_id(); int cpu = task_cpu(task); - int count = find_lowest_cpus(task, lowest_mask); - if (!count) - return -1; /* No targets found */ + if (task->rt.nr_cpus_allowed == 1) + return -1; /* No other targets possible */ - /* - * There is no sense in performing an optimal search if only one - * target is found. - */ - if (count == 1) - return first_cpu(*lowest_mask); + if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask)) + return -1; /* No targets found */ /* * At this point we have built a mask of cpus representing the @@ -1218,6 +1158,8 @@ static void join_domain_rt(struct rq *rq) { if (rq->rt.overloaded) rt_set_overload(rq); + + cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio); } /* Assumes rq->lock is held */ @@ -1225,6 +1167,8 @@ static void leave_domain_rt(struct rq *rq) { if (rq->rt.overloaded) rt_clear_overload(rq); + + cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID); } /* -- cgit v1.2.3-70-g09d2 From d07355f5def74d060333563b36ab51b89fd44cdd Mon Sep 17 00:00:00 2001 From: Dmitry Adamushko Date: Mon, 12 May 2008 21:21:15 +0200 Subject: sched: check for SD_SERIALIZE atomically in rebalance_domains() Nothing really serious here, mainly just a matter of nit-picking :-/ From: Dmitry Adamushko For CONFIG_SCHED_DEBUG && CONFIG_SYSCT configs, sd->flags can be altered while being manipulated in rebalance_domains(). Let's do an atomic check. We rely here on the atomicity of read/write accesses for aligned words. Signed-off-by: Dmitry Adamushko Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 8a1257b6556..90329f1f894 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3668,6 +3668,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) /* Earliest time when we have to do rebalance again */ unsigned long next_balance = jiffies + 60*HZ; int update_next_balance = 0; + int need_serialize; cpumask_t tmp; for_each_domain(cpu, sd) { @@ -3685,8 +3686,9 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) if (interval > HZ*NR_CPUS/10) interval = HZ*NR_CPUS/10; + need_serialize = sd->flags & SD_SERIALIZE; - if (sd->flags & SD_SERIALIZE) { + if (need_serialize) { if (!spin_trylock(&balancing)) goto out; } @@ -3702,7 +3704,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle) } sd->last_balance = jiffies; } - if (sd->flags & SD_SERIALIZE) + if (need_serialize) spin_unlock(&balancing); out: if (time_after(next_balance, sd->last_balance + interval)) { -- cgit v1.2.3-70-g09d2 From f7dcd80bbc8e7032443e6539ea1b830364f82200 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 24 May 2008 23:20:38 +0200 Subject: namespacecheck: fixes in kernel/sched.c Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 90329f1f894..02a5eeedcb9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1633,7 +1633,7 @@ inline int task_curr(const struct task_struct *p) } /* Used instead of source_load when we know the type == 0 */ -unsigned long weighted_cpuload(const int cpu) +static unsigned long weighted_cpuload(const int cpu) { return cpu_rq(cpu)->load.weight; } -- cgit v1.2.3-70-g09d2 From 81d41d7ece23a1c3b4bcd1604026d3a06cc4dc79 Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Sun, 11 May 2008 05:55:33 +0530 Subject: sched: fix defined-but-unused warning Fix this warning, which appears with !CONFIG_SMP: kernel/sched.c:1216: warning: `init_hrtick' defined but not used Signed-off-by: Rabin Vincent Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 02a5eeedcb9..f3faec52c5a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1130,6 +1130,7 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer) return HRTIMER_NORESTART; } +#ifdef CONFIG_SMP static void hotplug_hrtick_disable(int cpu) { struct rq *rq = cpu_rq(cpu); @@ -1185,6 +1186,7 @@ static void init_hrtick(void) { hotcpu_notifier(hotplug_hrtick, 0); } +#endif /* CONFIG_SMP */ static void init_rq_hrtick(struct rq *rq) { -- cgit v1.2.3-70-g09d2 From e21f5b153b9b4a6775d7d41964e372e13a9178ab Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Fri, 23 May 2008 09:05:58 -0700 Subject: sched: print module list in the "scheduling while atomic" warning For the normal WARN_ON() etc we added a print-the-modules-list already, which is very useful to figure out candidates for certain types of bugs. This patch adds the same print to the "scheduling while atomic" BUG warning, for the same reason: when we get here it's very useful to see which modules are loaded, to narrow down the candidate code list. Signed-off-by: Arjan van de Ven Cc: mingo@elte.hu Signed-off-by: Thomas Gleixner --- kernel/sched.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index f3faec52c5a..84a360670b9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4070,6 +4070,7 @@ static noinline void __schedule_bug(struct task_struct *prev) prev->comm, prev->pid, preempt_count()); debug_show_held_locks(prev); + print_modules(); if (irqs_disabled()) print_irqtrace_events(prev); -- cgit v1.2.3-70-g09d2 From 6d6bc0ad867c46896d0994bb039e7550ecb9b51d Mon Sep 17 00:00:00 2001 From: Dhaval Giani Date: Fri, 30 May 2008 14:23:45 +0200 Subject: sched: add comments for ifdefs in sched.c make sched.c easier to read. Signed-off-by: Dhaval Giani Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- kernel/sched.c | 76 +++++++++++++++++++++++++++++----------------------------- 1 file changed, 38 insertions(+), 38 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 84a360670b9..ef4e25604bb 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -292,15 +292,15 @@ struct task_group root_task_group; static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); /* Default task group's cfs_rq on each cpu */ static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; -#endif +#endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp; -#endif -#else +#endif /* CONFIG_RT_GROUP_SCHED */ +#else /* !CONFIG_FAIR_GROUP_SCHED */ #define root_task_group init_task_group -#endif +#endif /* CONFIG_FAIR_GROUP_SCHED */ /* task_group_lock serializes add/remove of task groups and also changes to * a task group's cpu shares. @@ -310,9 +310,9 @@ static DEFINE_SPINLOCK(task_group_lock); #ifdef CONFIG_FAIR_GROUP_SCHED #ifdef CONFIG_USER_SCHED # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD) -#else +#else /* !CONFIG_USER_SCHED */ # define INIT_TASK_GROUP_LOAD NICE_0_LOAD -#endif +#endif /* CONFIG_USER_SCHED */ /* * A weight of 0, 1 or ULONG_MAX can cause arithmetics problems. @@ -1316,15 +1316,15 @@ void wake_up_idle_cpu(int cpu) if (!tsk_is_polling(rq->idle)) smp_send_reschedule(cpu); } -#endif +#endif /* CONFIG_NO_HZ */ -#else +#else /* !CONFIG_SMP */ static void __resched_task(struct task_struct *p, int tif_bit) { assert_spin_locked(&task_rq(p)->lock); set_tsk_thread_flag(p, tif_bit); } -#endif +#endif /* CONFIG_SMP */ #if BITS_PER_LONG == 32 # define WMULT_CONST (~0UL) @@ -2129,7 +2129,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) } } } -#endif +#endif /* CONFIG_SCHEDSTATS */ out_activate: #endif /* CONFIG_SMP */ @@ -2329,7 +2329,7 @@ fire_sched_out_preempt_notifiers(struct task_struct *curr, notifier->ops->sched_out(notifier, next); } -#else +#else /* !CONFIG_PREEMPT_NOTIFIERS */ static void fire_sched_in_preempt_notifiers(struct task_struct *curr) { @@ -2341,7 +2341,7 @@ fire_sched_out_preempt_notifiers(struct task_struct *curr, { } -#endif +#endif /* CONFIG_PREEMPT_NOTIFIERS */ /** * prepare_task_switch - prepare to switch tasks @@ -6300,9 +6300,9 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu) } kfree(groupmask); } -#else +#else /* !CONFIG_SCHED_DEBUG */ # define sched_domain_debug(sd, cpu) do { } while (0) -#endif +#endif /* CONFIG_SCHED_DEBUG */ static int sd_degenerate(struct sched_domain *sd) { @@ -6598,7 +6598,7 @@ static void sched_domain_node_span(int node, cpumask_t *span) cpus_or(*span, *span, *nodemask); } } -#endif +#endif /* CONFIG_NUMA */ int sched_smt_power_savings = 0, sched_mc_power_savings = 0; @@ -6617,7 +6617,7 @@ cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg, *sg = &per_cpu(sched_group_cpus, cpu); return cpu; } -#endif +#endif /* CONFIG_SCHED_SMT */ /* * multi-core sched-domains: @@ -6625,7 +6625,7 @@ cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg, #ifdef CONFIG_SCHED_MC static DEFINE_PER_CPU(struct sched_domain, core_domains); static DEFINE_PER_CPU(struct sched_group, sched_group_core); -#endif +#endif /* CONFIG_SCHED_MC */ #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) static int @@ -6727,7 +6727,7 @@ static void init_numa_sched_groups_power(struct sched_group *group_head) sg = sg->next; } while (sg != group_head); } -#endif +#endif /* CONFIG_NUMA */ #ifdef CONFIG_NUMA /* Free memory allocated for various sched_group structures */ @@ -6764,11 +6764,11 @@ next_sg: sched_group_nodes_bycpu[cpu] = NULL; } } -#else +#else /* !CONFIG_NUMA */ static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask) { } -#endif +#endif /* CONFIG_NUMA */ /* * Initialize sched groups cpu_power. @@ -7459,7 +7459,7 @@ int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) #endif return err; } -#endif +#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ /* * Force a reinitialization of the sched domains hierarchy. The domains @@ -7677,8 +7677,8 @@ void __init sched_init(void) root_task_group.cfs_rq = (struct cfs_rq **)ptr; ptr += nr_cpu_ids * sizeof(void **); -#endif -#endif +#endif /* CONFIG_USER_SCHED */ +#endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED init_task_group.rt_se = (struct sched_rt_entity **)ptr; ptr += nr_cpu_ids * sizeof(void **); @@ -7692,8 +7692,8 @@ void __init sched_init(void) root_task_group.rt_rq = (struct rt_rq **)ptr; ptr += nr_cpu_ids * sizeof(void **); -#endif -#endif +#endif /* CONFIG_USER_SCHED */ +#endif /* CONFIG_RT_GROUP_SCHED */ } #ifdef CONFIG_SMP @@ -7709,8 +7709,8 @@ void __init sched_init(void) #ifdef CONFIG_USER_SCHED init_rt_bandwidth(&root_task_group.rt_bandwidth, global_rt_period(), RUNTIME_INF); -#endif -#endif +#endif /* CONFIG_USER_SCHED */ +#endif /* CONFIG_RT_GROUP_SCHED */ #ifdef CONFIG_GROUP_SCHED list_add(&init_task_group.list, &task_groups); @@ -7720,8 +7720,8 @@ void __init sched_init(void) INIT_LIST_HEAD(&root_task_group.children); init_task_group.parent = &root_task_group; list_add(&init_task_group.siblings, &root_task_group.children); -#endif -#endif +#endif /* CONFIG_USER_SCHED */ +#endif /* CONFIG_GROUP_SCHED */ for_each_possible_cpu(i) { struct rq *rq; @@ -8040,7 +8040,7 @@ static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) { list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list); } -#else +#else /* !CONFG_FAIR_GROUP_SCHED */ static inline void free_fair_sched_group(struct task_group *tg) { } @@ -8058,7 +8058,7 @@ static inline void register_fair_sched_group(struct task_group *tg, int cpu) static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) { } -#endif +#endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED static void free_rt_sched_group(struct task_group *tg) @@ -8129,7 +8129,7 @@ static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) { list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list); } -#else +#else /* !CONFIG_RT_GROUP_SCHED */ static inline void free_rt_sched_group(struct task_group *tg) { } @@ -8147,7 +8147,7 @@ static inline void register_rt_sched_group(struct task_group *tg, int cpu) static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) { } -#endif +#endif /* CONFIG_RT_GROUP_SCHED */ #ifdef CONFIG_GROUP_SCHED static void free_sched_group(struct task_group *tg) @@ -8258,7 +8258,7 @@ void sched_move_task(struct task_struct *tsk) task_rq_unlock(rq, &flags); } -#endif +#endif /* CONFIG_GROUP_SCHED */ #ifdef CONFIG_FAIR_GROUP_SCHED static void set_se_shares(struct sched_entity *se, unsigned long shares) @@ -8508,7 +8508,7 @@ static int sched_rt_global_constraints(void) return ret; } -#else +#else /* !CONFIG_RT_GROUP_SCHED */ static int sched_rt_global_constraints(void) { unsigned long flags; @@ -8526,7 +8526,7 @@ static int sched_rt_global_constraints(void) return 0; } -#endif +#endif /* CONFIG_RT_GROUP_SCHED */ int sched_rt_handler(struct ctl_table *table, int write, struct file *filp, void __user *buffer, size_t *lenp, @@ -8634,7 +8634,7 @@ static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) return (u64) tg->shares; } -#endif +#endif /* CONFIG_FAIR_GROUP_SCHED */ #ifdef CONFIG_RT_GROUP_SCHED static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, @@ -8658,7 +8658,7 @@ static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) { return sched_group_rt_period(cgroup_tg(cgrp)); } -#endif +#endif /* CONFIG_RT_GROUP_SCHED */ static struct cftype cpu_files[] = { #ifdef CONFIG_FAIR_GROUP_SCHED -- cgit v1.2.3-70-g09d2 From 099f98c8a1f13501a98afbfff4756395a610581c Mon Sep 17 00:00:00 2001 From: Gautham R Shenoy Date: Thu, 29 May 2008 20:56:32 +0530 Subject: sched: print the sd->level in sched_domain_debug code While printing out the visual representation of the sched-domains, print the level (MC, SMT, CPU, NODE, ... ) of each of the sched_domains. Credit: Peter Zijlstra Signed-off-by: Gautham R Shenoy Signed-off-by: Ingo Molnar --- kernel/sched.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index ef4e25604bb..dc0be113f41 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6197,6 +6197,28 @@ void __init migration_init(void) #ifdef CONFIG_SCHED_DEBUG +static inline const char *sd_level_to_string(enum sched_domain_level lvl) +{ + switch (lvl) { + case SD_LV_NONE: + return "NONE"; + case SD_LV_SIBLING: + return "SIBLING"; + case SD_LV_MC: + return "MC"; + case SD_LV_CPU: + return "CPU"; + case SD_LV_NODE: + return "NODE"; + case SD_LV_ALLNODES: + return "ALLNODES"; + case SD_LV_MAX: + return "MAX"; + + } + return "MAX"; +} + static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, cpumask_t *groupmask) { @@ -6216,7 +6238,8 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, return -1; } - printk(KERN_CONT "span %s\n", str); + printk(KERN_CONT "span %s level %s\n", + str, sd_level_to_string(sd->level)); if (!cpu_isset(cpu, sd->span)) { printk(KERN_ERR "ERROR: domain->span does not contain " -- cgit v1.2.3-70-g09d2 From 1f11eb6a8bc92536d9e93ead48fa3ffbd1478571 Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Wed, 4 Jun 2008 15:04:05 -0400 Subject: sched: fix cpupri hotplug support The RT folks over at RedHat found an issue w.r.t. hotplug support which was traced to problems with the cpupri infrastructure in the scheduler: https://bugzilla.redhat.com/show_bug.cgi?id=449676 This bug affects 23-rt12+, 24-rtX, 25-rtX, and sched-devel. This patch applies to 25.4-rt4, though it should trivially apply to most cpupri enabled kernels mentioned above. It turned out that the issue was that offline cpus could get inadvertently registered with cpupri so that they were erroneously selected during migration decisions. The end result would be an OOPS as the offline cpu had tasks routed to it. This patch generalizes the old join/leave domain interface into an online/offline interface, and adjusts the root-domain/hotplug code to utilize it. I was able to easily reproduce the issue prior to this patch, and am no longer able to reproduce it after this patch. I can offline cpus indefinately and everything seems to be in working order. Thanks to Arnaldo (acme), Thomas, and Peter for doing the legwork to point me in the right direction. Also thank you to Peter for reviewing the early iterations of this patch. Signed-off-by: Gregory Haskins Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Ingo Molnar Signed-off-by: Thomas Gleixner --- include/linux/sched.h | 4 ++-- kernel/sched.c | 54 ++++++++++++++++++++++++++++++++++++++------------- kernel/sched_rt.c | 24 +++++++++++++++++------ 3 files changed, 60 insertions(+), 22 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index ea2857b9959..d25acf600a3 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -903,8 +903,8 @@ struct sched_class { void (*set_cpus_allowed)(struct task_struct *p, const cpumask_t *newmask); - void (*join_domain)(struct rq *rq); - void (*leave_domain)(struct rq *rq); + void (*rq_online)(struct rq *rq); + void (*rq_offline)(struct rq *rq); void (*switched_from) (struct rq *this_rq, struct task_struct *task, int running); diff --git a/kernel/sched.c b/kernel/sched.c index dc0be113f41..f0ed81b7128 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -529,6 +529,7 @@ struct rq { int push_cpu; /* cpu of this runqueue: */ int cpu; + int online; struct task_struct *migration_thread; struct list_head migration_queue; @@ -1498,6 +1499,8 @@ static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) #endif #define sched_class_highest (&rt_sched_class) +#define for_each_class(class) \ + for (class = sched_class_highest; class; class = class->next) static inline void inc_load(struct rq *rq, const struct task_struct *p) { @@ -6065,6 +6068,36 @@ static void unregister_sched_domain_sysctl(void) } #endif +static void set_rq_online(struct rq *rq) +{ + if (!rq->online) { + const struct sched_class *class; + + cpu_set(rq->cpu, rq->rd->online); + rq->online = 1; + + for_each_class(class) { + if (class->rq_online) + class->rq_online(rq); + } + } +} + +static void set_rq_offline(struct rq *rq) +{ + if (rq->online) { + const struct sched_class *class; + + for_each_class(class) { + if (class->rq_offline) + class->rq_offline(rq); + } + + cpu_clear(rq->cpu, rq->rd->online); + rq->online = 0; + } +} + /* * migration_call - callback that gets triggered when a CPU is added. * Here we can start up the necessary migration thread for the new CPU. @@ -6102,7 +6135,8 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { BUG_ON(!cpu_isset(cpu, rq->rd->span)); - cpu_set(cpu, rq->rd->online); + + set_rq_online(rq); } spin_unlock_irqrestore(&rq->lock, flags); break; @@ -6163,7 +6197,7 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { BUG_ON(!cpu_isset(cpu, rq->rd->span)); - cpu_clear(cpu, rq->rd->online); + set_rq_offline(rq); } spin_unlock_irqrestore(&rq->lock, flags); break; @@ -6385,20 +6419,16 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) static void rq_attach_root(struct rq *rq, struct root_domain *rd) { unsigned long flags; - const struct sched_class *class; spin_lock_irqsave(&rq->lock, flags); if (rq->rd) { struct root_domain *old_rd = rq->rd; - for (class = sched_class_highest; class; class = class->next) { - if (class->leave_domain) - class->leave_domain(rq); - } + if (cpu_isset(rq->cpu, old_rd->online)) + set_rq_offline(rq); cpu_clear(rq->cpu, old_rd->span); - cpu_clear(rq->cpu, old_rd->online); if (atomic_dec_and_test(&old_rd->refcount)) kfree(old_rd); @@ -6409,12 +6439,7 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd) cpu_set(rq->cpu, rd->span); if (cpu_isset(rq->cpu, cpu_online_map)) - cpu_set(rq->cpu, rd->online); - - for (class = sched_class_highest; class; class = class->next) { - if (class->join_domain) - class->join_domain(rq); - } + set_rq_online(rq); spin_unlock_irqrestore(&rq->lock, flags); } @@ -7824,6 +7849,7 @@ void __init sched_init(void) rq->next_balance = jiffies; rq->push_cpu = 0; rq->cpu = i; + rq->online = 0; rq->migration_thread = NULL; INIT_LIST_HEAD(&rq->migration_queue); rq_attach_root(rq, &def_root_domain); diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 44b06d75416..e4821593d4d 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -12,6 +12,9 @@ static inline int rt_overloaded(struct rq *rq) static inline void rt_set_overload(struct rq *rq) { + if (!rq->online) + return; + cpu_set(rq->cpu, rq->rd->rto_mask); /* * Make sure the mask is visible before we set @@ -26,6 +29,9 @@ static inline void rt_set_overload(struct rq *rq) static inline void rt_clear_overload(struct rq *rq) { + if (!rq->online) + return; + /* the order here really doesn't matter */ atomic_dec(&rq->rd->rto_count); cpu_clear(rq->cpu, rq->rd->rto_mask); @@ -394,7 +400,10 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) if (rt_se_prio(rt_se) < rt_rq->highest_prio) { struct rq *rq = rq_of_rt_rq(rt_rq); rt_rq->highest_prio = rt_se_prio(rt_se); - cpupri_set(&rq->rd->cpupri, rq->cpu, rt_se_prio(rt_se)); + + if (rq->online) + cpupri_set(&rq->rd->cpupri, rq->cpu, + rt_se_prio(rt_se)); } #endif #ifdef CONFIG_SMP @@ -448,7 +457,10 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) if (rt_rq->highest_prio != highest_prio) { struct rq *rq = rq_of_rt_rq(rt_rq); - cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio); + + if (rq->online) + cpupri_set(&rq->rd->cpupri, rq->cpu, + rt_rq->highest_prio); } update_rt_migration(rq_of_rt_rq(rt_rq)); @@ -1154,7 +1166,7 @@ static void set_cpus_allowed_rt(struct task_struct *p, } /* Assumes rq->lock is held */ -static void join_domain_rt(struct rq *rq) +static void rq_online_rt(struct rq *rq) { if (rq->rt.overloaded) rt_set_overload(rq); @@ -1163,7 +1175,7 @@ static void join_domain_rt(struct rq *rq) } /* Assumes rq->lock is held */ -static void leave_domain_rt(struct rq *rq) +static void rq_offline_rt(struct rq *rq) { if (rq->rt.overloaded) rt_clear_overload(rq); @@ -1331,8 +1343,8 @@ static const struct sched_class rt_sched_class = { .load_balance = load_balance_rt, .move_one_task = move_one_task_rt, .set_cpus_allowed = set_cpus_allowed_rt, - .join_domain = join_domain_rt, - .leave_domain = leave_domain_rt, + .rq_online = rq_online_rt, + .rq_offline = rq_offline_rt, .pre_schedule = pre_schedule_rt, .post_schedule = post_schedule_rt, .task_wake_up = task_wake_up_rt, -- cgit v1.2.3-70-g09d2 From 5c8e1ed1d204a6770ca2854cd3b3597070fe7e5a Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Thu, 29 May 2008 11:17:01 -0700 Subject: sched: CPU hotplug events must not destroy scheduler domains created by the cpusets First issue is not related to the cpusets. We're simply leaking doms_cur. It's allocated in arch_init_sched_domains() which is called for every hotplug event. So we just keep reallocation doms_cur without freeing it. I introduced free_sched_domains() function that cleans things up. Second issue is that sched domains created by the cpusets are completely destroyed by the CPU hotplug events. For all CPU hotplug events scheduler attaches all CPUs to the NULL domain and then puts them all into the single domain thereby destroying domains created by the cpusets (partition_sched_domains). The solution is simple, when cpusets are enabled scheduler should not create default domain and instead let cpusets do that. Which is exactly what the patch does. Signed-off-by: Max Krasnyansky Cc: pj@sgi.com Cc: menage@google.com Cc: rostedt@goodmis.org Cc: mingo@elte.hu Acked-by: Peter Zijlstra Signed-off-by: Thomas Gleixner --- kernel/cpuset.c | 6 ++++++ kernel/sched.c | 22 ++++++++++++++++++++++ 2 files changed, 28 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 86ea9e34e32..6090d18b58a 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1886,6 +1886,12 @@ static void common_cpu_mem_hotplug_unplug(void) top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY]; scan_for_empty_cpusets(&top_cpuset); + /* + * Scheduler destroys domains on hotplug events. + * Rebuild them based on the current settings. + */ + rebuild_sched_domains(); + cgroup_unlock(); } diff --git a/kernel/sched.c b/kernel/sched.c index f0ed81b7128..1ddb0a8c797 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7292,6 +7292,18 @@ void __attribute__((weak)) arch_update_cpu_topology(void) { } +/* + * Free current domain masks. + * Called after all cpus are attached to NULL domain. + */ +static void free_sched_domains(void) +{ + ndoms_cur = 0; + if (doms_cur != &fallback_doms) + kfree(doms_cur); + doms_cur = &fallback_doms; +} + /* * Set up scheduler domains and groups. Callers must hold the hotplug lock. * For now this just excludes isolated cpus, but could be used to @@ -7439,6 +7451,7 @@ int arch_reinit_sched_domains(void) get_online_cpus(); mutex_lock(&sched_domains_mutex); detach_destroy_domains(&cpu_online_map); + free_sched_domains(); err = arch_init_sched_domains(&cpu_online_map); mutex_unlock(&sched_domains_mutex); put_online_cpus(); @@ -7524,6 +7537,7 @@ static int update_sched_domains(struct notifier_block *nfb, case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: detach_destroy_domains(&cpu_online_map); + free_sched_domains(); return NOTIFY_OK; case CPU_UP_CANCELED: @@ -7542,8 +7556,16 @@ static int update_sched_domains(struct notifier_block *nfb, return NOTIFY_DONE; } +#ifndef CONFIG_CPUSETS + /* + * Create default domain partitioning if cpusets are disabled. + * Otherwise we let cpusets rebuild the domains based on the + * current setup. + */ + /* The hotplug lock is already held by cpu_up/cpu_down */ arch_init_sched_domains(&cpu_online_map); +#endif return NOTIFY_OK; } -- cgit v1.2.3-70-g09d2 From 68f4f1ec08e3d95730a2693b99df8260aa0d06ae Mon Sep 17 00:00:00 2001 From: Max Krasnyansky Date: Thu, 29 May 2008 11:17:02 -0700 Subject: sched: Move cpu masks from kernel/sched.c into kernel/cpu.c kernel/cpu.c seems a more logical place for those maps since they do not really have much to do with the scheduler these days. kernel/cpu.c is now built for the UP kernel too, but it does not affect the size the kernel sections. $ size vmlinux before text data bss dec hex filename 3313797 307060 310352 3931209 3bfc49 vmlinux after text data bss dec hex filename 3313797 307060 310352 3931209 3bfc49 vmlinux Signed-off-by: Max Krasnyansky Cc: pj@sgi.com Cc: menage@google.com Cc: rostedt@goodmis.org Cc: mingo@elte.hu Acked-by: Peter Zijlstra Signed-off-by: Thomas Gleixner --- kernel/Makefile | 4 ++-- kernel/cpu.c | 24 ++++++++++++++++++++++++ kernel/sched.c | 18 ------------------ 3 files changed, 26 insertions(+), 20 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/Makefile b/kernel/Makefile index ecdd2d33563..6c55301112e 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -3,7 +3,7 @@ # obj-y = sched.o fork.o exec_domain.o panic.o printk.o profile.o \ - exit.o itimer.o time.o softirq.o resource.o \ + cpu.o exit.o itimer.o time.o softirq.o resource.o \ sysctl.o capability.o ptrace.o timer.o user.o \ signal.o sys.o kmod.o workqueue.o pid.o \ rcupdate.o extable.o params.o posix-timers.o \ @@ -27,7 +27,7 @@ obj-$(CONFIG_RT_MUTEXES) += rtmutex.o obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o -obj-$(CONFIG_SMP) += cpu.o spinlock.o +obj-$(CONFIG_SMP) += spinlock.o obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o obj-$(CONFIG_PROVE_LOCKING) += spinlock.o obj-$(CONFIG_UID16) += uid16.o diff --git a/kernel/cpu.c b/kernel/cpu.c index c77bc3a1c72..b11f06dc149 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -15,6 +15,28 @@ #include #include +/* + * Represents all cpu's present in the system + * In systems capable of hotplug, this map could dynamically grow + * as new cpu's are detected in the system via any platform specific + * method, such as ACPI for e.g. + */ +cpumask_t cpu_present_map __read_mostly; +EXPORT_SYMBOL(cpu_present_map); + +#ifndef CONFIG_SMP + +/* + * Represents all cpu's that are currently online. + */ +cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; +EXPORT_SYMBOL(cpu_online_map); + +cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; +EXPORT_SYMBOL(cpu_possible_map); + +#else /* CONFIG_SMP */ + /* Serializes the updates to cpu_online_map, cpu_present_map */ static DEFINE_MUTEX(cpu_add_remove_lock); @@ -403,3 +425,5 @@ out: cpu_maps_update_done(); } #endif /* CONFIG_PM_SLEEP_SMP */ + +#endif /* CONFIG_SMP */ diff --git a/kernel/sched.c b/kernel/sched.c index 1ddb0a8c797..f36f549e574 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5080,24 +5080,6 @@ asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, return sched_setaffinity(pid, &new_mask); } -/* - * Represents all cpu's present in the system - * In systems capable of hotplug, this map could dynamically grow - * as new cpu's are detected in the system via any platform specific - * method, such as ACPI for e.g. - */ - -cpumask_t cpu_present_map __read_mostly; -EXPORT_SYMBOL(cpu_present_map); - -#ifndef CONFIG_SMP -cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; -EXPORT_SYMBOL(cpu_online_map); - -cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; -EXPORT_SYMBOL(cpu_possible_map); -#endif - long sched_getaffinity(pid_t pid, cpumask_t *mask) { struct task_struct *p; -- cgit v1.2.3-70-g09d2 From e958b3600484533ff801920290468adc8135f89d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 4 Jun 2008 23:22:32 +0200 Subject: sched: move weighted_cpuload into #ifdef CONFIG_SMP section weighted_cpuload is only used on SMP. move it into the CONFIG_SMP section. Signed-off-by: Thomas Gleixner --- kernel/sched.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index f36f549e574..727bdef7616 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1637,12 +1637,6 @@ inline int task_curr(const struct task_struct *p) return cpu_curr(task_cpu(p)) == p; } -/* Used instead of source_load when we know the type == 0 */ -static unsigned long weighted_cpuload(const int cpu) -{ - return cpu_rq(cpu)->load.weight; -} - static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) { set_task_rq(p, cpu); @@ -1671,6 +1665,12 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p, #ifdef CONFIG_SMP +/* Used instead of source_load when we know the type == 0 */ +static unsigned long weighted_cpuload(const int cpu) +{ + return cpu_rq(cpu)->load.weight; +} + /* * Is this task likely cache-hot: */ -- cgit v1.2.3-70-g09d2 From 7def2be1dc679984f4c4fb3ef19a8a081b2454ec Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 5 Jun 2008 14:49:58 +0200 Subject: sched: fix hotplug cpus on ia64 Cliff Wickman wrote: > I built an ia64 kernel from Andrew's tree (2.6.26-rc2-mm1) > and get a very predictable hotplug cpu problem. > billberry1:/tmp/cpw # ./dis > disabled cpu 17 > enabled cpu 17 > billberry1:/tmp/cpw # ./dis > disabled cpu 17 > enabled cpu 17 > billberry1:/tmp/cpw # ./dis > > The script that disables the cpu always hangs (unkillable) > on the 3rd attempt. > > And a bit further: > The kstopmachine thread always sits on the run queue (real time) for about > 30 minutes before running. this fix solves some (but not all) issues between CPU hotplug and RT bandwidth throttling. Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 15 ++++++-- kernel/sched_rt.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 115 insertions(+), 9 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 727bdef7616..e9c24a12865 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7513,21 +7513,28 @@ int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) static int update_sched_domains(struct notifier_block *nfb, unsigned long action, void *hcpu) { + int cpu = (int)(long)hcpu; + switch (action) { - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: + disable_runtime(cpu_rq(cpu)); + /* fall-through */ + case CPU_UP_PREPARE: + case CPU_UP_PREPARE_FROZEN: detach_destroy_domains(&cpu_online_map); free_sched_domains(); return NOTIFY_OK; - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: + case CPU_DOWN_FAILED: case CPU_DOWN_FAILED_FROZEN: case CPU_ONLINE: case CPU_ONLINE_FROZEN: + enable_runtime(cpu_rq(cpu)); + /* fall-through */ + case CPU_UP_CANCELED: + case CPU_UP_CANCELED_FROZEN: case CPU_DEAD: case CPU_DEAD_FROZEN: /* diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index eaa606071d5..8ae3416e0bb 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -286,6 +286,9 @@ static int balance_runtime(struct rt_rq *rt_rq) continue; spin_lock(&iter->rt_runtime_lock); + if (iter->rt_runtime == RUNTIME_INF) + goto next; + diff = iter->rt_runtime - iter->rt_time; if (diff > 0) { do_div(diff, weight); @@ -299,12 +302,105 @@ static int balance_runtime(struct rt_rq *rt_rq) break; } } +next: spin_unlock(&iter->rt_runtime_lock); } spin_unlock(&rt_b->rt_runtime_lock); return more; } + +static void __disable_runtime(struct rq *rq) +{ + struct root_domain *rd = rq->rd; + struct rt_rq *rt_rq; + + if (unlikely(!scheduler_running)) + return; + + for_each_leaf_rt_rq(rt_rq, rq) { + struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); + s64 want; + int i; + + spin_lock(&rt_b->rt_runtime_lock); + spin_lock(&rt_rq->rt_runtime_lock); + if (rt_rq->rt_runtime == RUNTIME_INF || + rt_rq->rt_runtime == rt_b->rt_runtime) + goto balanced; + spin_unlock(&rt_rq->rt_runtime_lock); + + want = rt_b->rt_runtime - rt_rq->rt_runtime; + + for_each_cpu_mask(i, rd->span) { + struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i); + s64 diff; + + if (iter == rt_rq) + continue; + + spin_lock(&iter->rt_runtime_lock); + if (want > 0) { + diff = min_t(s64, iter->rt_runtime, want); + iter->rt_runtime -= diff; + want -= diff; + } else { + iter->rt_runtime -= want; + want -= want; + } + spin_unlock(&iter->rt_runtime_lock); + + if (!want) + break; + } + + spin_lock(&rt_rq->rt_runtime_lock); + BUG_ON(want); +balanced: + rt_rq->rt_runtime = RUNTIME_INF; + spin_unlock(&rt_rq->rt_runtime_lock); + spin_unlock(&rt_b->rt_runtime_lock); + } +} + +static void disable_runtime(struct rq *rq) +{ + unsigned long flags; + + spin_lock_irqsave(&rq->lock, flags); + __disable_runtime(rq); + spin_unlock_irqrestore(&rq->lock, flags); +} + +static void __enable_runtime(struct rq *rq) +{ + struct root_domain *rd = rq->rd; + struct rt_rq *rt_rq; + + if (unlikely(!scheduler_running)) + return; + + for_each_leaf_rt_rq(rt_rq, rq) { + struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); + + spin_lock(&rt_b->rt_runtime_lock); + spin_lock(&rt_rq->rt_runtime_lock); + rt_rq->rt_runtime = rt_b->rt_runtime; + rt_rq->rt_time = 0; + spin_unlock(&rt_rq->rt_runtime_lock); + spin_unlock(&rt_b->rt_runtime_lock); + } +} + +static void enable_runtime(struct rq *rq) +{ + unsigned long flags; + + spin_lock_irqsave(&rq->lock, flags); + __enable_runtime(rq); + spin_unlock_irqrestore(&rq->lock, flags); +} + #endif static inline int rt_se_prio(struct sched_rt_entity *rt_se) @@ -334,14 +430,13 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) #ifdef CONFIG_SMP if (rt_rq->rt_time > runtime) { - int more; - spin_unlock(&rt_rq->rt_runtime_lock); - more = balance_runtime(rt_rq); + balance_runtime(rt_rq); spin_lock(&rt_rq->rt_runtime_lock); - if (more) - runtime = sched_rt_runtime(rt_rq); + runtime = sched_rt_runtime(rt_rq); + if (runtime == RUNTIME_INF) + return 0; } #endif @@ -1174,6 +1269,8 @@ static void rq_online_rt(struct rq *rq) if (rq->rt.overloaded) rt_set_overload(rq); + __enable_runtime(rq); + cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio); } @@ -1183,6 +1280,8 @@ static void rq_offline_rt(struct rq *rq) if (rq->rt.overloaded) rt_clear_overload(rq); + __disable_runtime(rq); + cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID); } -- cgit v1.2.3-70-g09d2 From 9985b0bab332289f14837eff3c6e0bcc658b58f7 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Thu, 5 Jun 2008 12:57:11 -0700 Subject: sched: prevent bound kthreads from changing cpus_allowed Kthreads that have called kthread_bind() are bound to specific cpus, so other tasks should not be able to change their cpus_allowed from under them. Otherwise, it is possible to move kthreads, such as the migration or software watchdog threads, so they are not allowed access to the cpu they work on. Cc: Peter Zijlstra Cc: Paul Menage Cc: Paul Jackson Signed-off-by: David Rientjes Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + kernel/cpuset.c | 14 +++++++++++++- kernel/kthread.c | 1 + kernel/sched.c | 6 ++++++ 4 files changed, 21 insertions(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index d25acf600a3..2db1485f865 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1486,6 +1486,7 @@ static inline void put_task_struct(struct task_struct *t) #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */ #define PF_SPREAD_PAGE 0x01000000 /* Spread page cache over cpuset */ #define PF_SPREAD_SLAB 0x02000000 /* Spread some slab caches over cpuset */ +#define PF_THREAD_BOUND 0x04000000 /* Thread bound to specific cpu */ #define PF_MEMPOLICY 0x10000000 /* Non-default NUMA mempolicy */ #define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */ #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezeable */ diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 6090d18b58a..b84354f4de3 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1190,6 +1190,15 @@ static int cpuset_can_attach(struct cgroup_subsys *ss, if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)) return -ENOSPC; + if (tsk->flags & PF_THREAD_BOUND) { + cpumask_t mask; + + mutex_lock(&callback_mutex); + mask = cs->cpus_allowed; + mutex_unlock(&callback_mutex); + if (!cpus_equal(tsk->cpus_allowed, mask)) + return -EINVAL; + } return security_task_setscheduler(tsk, 0, NULL); } @@ -1203,11 +1212,14 @@ static void cpuset_attach(struct cgroup_subsys *ss, struct mm_struct *mm; struct cpuset *cs = cgroup_cs(cont); struct cpuset *oldcs = cgroup_cs(oldcont); + int err; mutex_lock(&callback_mutex); guarantee_online_cpus(cs, &cpus); - set_cpus_allowed_ptr(tsk, &cpus); + err = set_cpus_allowed_ptr(tsk, &cpus); mutex_unlock(&callback_mutex); + if (err) + return; from = oldcs->mems_allowed; to = cs->mems_allowed; diff --git a/kernel/kthread.c b/kernel/kthread.c index bd1b9ea024e..97747cdd37c 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -180,6 +180,7 @@ void kthread_bind(struct task_struct *k, unsigned int cpu) set_task_cpu(k, cpu); k->cpus_allowed = cpumask_of_cpu(cpu); k->rt.nr_cpus_allowed = 1; + k->flags |= PF_THREAD_BOUND; } EXPORT_SYMBOL(kthread_bind); diff --git a/kernel/sched.c b/kernel/sched.c index e9c24a12865..164fe7fe0d8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5563,6 +5563,12 @@ int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask) goto out; } + if (unlikely((p->flags & PF_THREAD_BOUND) && p != current && + !cpus_equal(p->cpus_allowed, *new_mask))) { + ret = -EINVAL; + goto out; + } + if (p->sched_class->set_cpus_allowed) p->sched_class->set_cpus_allowed(p, new_mask); else { -- cgit v1.2.3-70-g09d2 From e9886ca3a93d7d041d3de8e5acebe213da777d59 Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Mon, 9 Jun 2008 17:12:24 +0900 Subject: sched: kill off dead cfs_rq_set_shares() Building with CONFIG_FAIR_GROUP_SCHED=y on UP results in an unused cfs_rq_set_shares() reference. As nothing is using this dummy function in the first place, just kill it off. Signed-off-by: Paul Mundt Signed-off-by: Ingo Molnar --- kernel/sched.c | 8 -------- 1 file changed, 8 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 164fe7fe0d8..07d5472dee9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1480,16 +1480,8 @@ static unsigned long source_load(int cpu, int type); static unsigned long target_load(int cpu, int type); static unsigned long cpu_avg_load_per_task(int cpu); static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); -#else /* CONFIG_SMP */ - -#ifdef CONFIG_FAIR_GROUP_SCHED -static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) -{ -} #endif -#endif /* CONFIG_SMP */ - #include "sched_stats.h" #include "sched_idletask.c" #include "sched_fair.c" -- cgit v1.2.3-70-g09d2 From 040ec23d07f95285e9777a85cda29cb339a3065b Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 9 Jun 2008 01:45:29 -0700 Subject: sched: sched_clock() lockdep fix Sitsofe Wheeler bisected the following commit to cause a lockdep to warn about itself and turn itself off: > commit c6531cce6e6e4b99bcda46b6268d6f2d9e30aea4 > Author: Ingo Molnar > Date: Mon May 12 21:21:14 2008 +0200 > > sched: do not trace sched_clock do not use raw irq flags in cpu_clock() as it causes lockdep to lose track of the true state of the IRQ flag. Reported-and-bisected-by: Sitsofe Wheeler Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton --- kernel/sched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 6590a828138..b8c9fe67622 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -889,7 +889,7 @@ unsigned long long notrace cpu_clock(int cpu) unsigned long long prev_cpu_time, time, delta_time; unsigned long flags; - raw_local_irq_save(flags); + local_irq_save(flags); prev_cpu_time = per_cpu(prev_cpu_time, cpu); time = __cpu_clock(cpu) + per_cpu(time_offset, cpu); delta_time = time-prev_cpu_time; @@ -898,7 +898,7 @@ unsigned long long notrace cpu_clock(int cpu) time = __sync_cpu_clock(time, cpu); per_cpu(prev_cpu_time, cpu) = time; } - raw_local_irq_restore(flags); + local_irq_restore(flags); return time; } -- cgit v1.2.3-70-g09d2 From 20b6331bfed1f07ba1e5006889a5d64adc53615e Mon Sep 17 00:00:00 2001 From: Dmitry Adamushko Date: Wed, 11 Jun 2008 00:58:30 +0200 Subject: sched: rework of "prioritize non-migratable tasks over migratable ones" regarding this commit: 45c01e824991b2dd0a332e19efc4901acb31209f I think we can do it simpler. Please take a look at the patch below. Instead of having 2 separate arrays (which is + ~800 bytes on x86_32 and twice so on x86_64), let's add "exclusive" (the ones that are bound to this CPU) tasks to the head of the queue and "shared" ones -- to the end. In case of a few newly woken up "exclusive" tasks, they are 'stacked' (not queued as now), meaning that a task {i+1} is being placed in front of the previously woken up task {i}. But I don't think that this behavior may cause any realistic problems. There are a couple of changes on top of this one. (1) in check_preempt_curr_rt() I don't think there is a need for the "pick_next_rt_entity(rq, &rq->rt) != &rq->curr->rt" check. enqueue_task_rt(p) and check_preempt_curr_rt() are always called one after another with rq->lock being held so the following check "p->rt.nr_cpus_allowed == 1 && rq->curr->rt.nr_cpus_allowed != 1" should be enough (well, just its left part) to guarantee that 'p' has been queued in front of the 'curr'. (2) in set_cpus_allowed_rt() I don't thinks there is a need for requeue_task_rt() here. Perhaps, the only case when 'requeue' (+ reschedule) might be useful is as follows: i) weight == 1 && cpu_isset(task_cpu(p), *new_mask) i.e. a task is being bound to this CPU); ii) 'p' != rq->curr but here, 'p' has already been on this CPU for a while and was not migrated. i.e. it's possible that 'rq->curr' would not have high chances to be migrated right at this particular moment (although, has chance in a bit longer term), should we allow it to be preempted. Anyway, I think we should not perhaps make it more complex trying to address some rare corner cases. For instance, that's why a single queue approach would be preferable. Unless I'm missing something obvious, this approach gives us similar functionality at lower cost. Verified only compilation-wise. (Almost)-Signed-off-by: Dmitry Adamushko Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++---- kernel/sched_rt.c | 44 +++++++++----------------------------------- 2 files changed, 11 insertions(+), 39 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 554de400980..cc1d558406f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -153,8 +153,7 @@ static inline int task_has_rt_policy(struct task_struct *p) */ struct rt_prio_array { DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ - struct list_head xqueue[MAX_RT_PRIO]; /* exclusive queue */ - struct list_head squeue[MAX_RT_PRIO]; /* shared queue */ + struct list_head queue[MAX_RT_PRIO]; }; struct rt_bandwidth { @@ -7620,8 +7619,7 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) array = &rt_rq->active; for (i = 0; i < MAX_RT_PRIO; i++) { - INIT_LIST_HEAD(array->xqueue + i); - INIT_LIST_HEAD(array->squeue + i); + INIT_LIST_HEAD(array->queue + i); __clear_bit(i, array->bitmap); } /* delimiter for bitsearch: */ diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 8ae3416e0bb..f721b52acd8 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -576,16 +576,15 @@ static void enqueue_rt_entity(struct sched_rt_entity *rt_se) struct rt_rq *rt_rq = rt_rq_of_se(rt_se); struct rt_prio_array *array = &rt_rq->active; struct rt_rq *group_rq = group_rt_rq(rt_se); + struct list_head *queue = array->queue + rt_se_prio(rt_se); if (group_rq && rt_rq_throttled(group_rq)) return; if (rt_se->nr_cpus_allowed == 1) - list_add_tail(&rt_se->run_list, - array->xqueue + rt_se_prio(rt_se)); + list_add(&rt_se->run_list, queue); else - list_add_tail(&rt_se->run_list, - array->squeue + rt_se_prio(rt_se)); + list_add_tail(&rt_se->run_list, queue); __set_bit(rt_se_prio(rt_se), array->bitmap); @@ -598,8 +597,7 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se) struct rt_prio_array *array = &rt_rq->active; list_del_init(&rt_se->run_list); - if (list_empty(array->squeue + rt_se_prio(rt_se)) - && list_empty(array->xqueue + rt_se_prio(rt_se))) + if (list_empty(array->queue + rt_se_prio(rt_se))) __clear_bit(rt_se_prio(rt_se), array->bitmap); dec_rt_tasks(rt_se, rt_rq); @@ -666,11 +664,6 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) /* * Put task to the end of the run list without the overhead of dequeue * followed by enqueue. - * - * Note: We always enqueue the task to the shared-queue, regardless of its - * previous position w.r.t. exclusive vs shared. This is so that exclusive RR - * tasks fairly round-robin with all tasks on the runqueue, not just other - * exclusive tasks. */ static void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) @@ -678,7 +671,7 @@ void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) struct rt_prio_array *array = &rt_rq->active; list_del_init(&rt_se->run_list); - list_add_tail(&rt_se->run_list, array->squeue + rt_se_prio(rt_se)); + list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se)); } static void requeue_task_rt(struct rq *rq, struct task_struct *p) @@ -736,9 +729,6 @@ static int select_task_rq_rt(struct task_struct *p, int sync) } #endif /* CONFIG_SMP */ -static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, - struct rt_rq *rt_rq); - /* * Preempt the current task with a newly woken task if needed: */ @@ -764,8 +754,7 @@ static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p) */ if((p->prio == rq->curr->prio) && p->rt.nr_cpus_allowed == 1 - && rq->curr->rt.nr_cpus_allowed != 1 - && pick_next_rt_entity(rq, &rq->rt) != &rq->curr->rt) { + && rq->curr->rt.nr_cpus_allowed != 1) { cpumask_t mask; if (cpupri_find(&rq->rd->cpupri, rq->curr, &mask)) @@ -789,15 +778,8 @@ static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, idx = sched_find_first_bit(array->bitmap); BUG_ON(idx >= MAX_RT_PRIO); - queue = array->xqueue + idx; - if (!list_empty(queue)) - next = list_entry(queue->next, struct sched_rt_entity, - run_list); - else { - queue = array->squeue + idx; - next = list_entry(queue->next, struct sched_rt_entity, - run_list); - } + queue = array->queue + idx; + next = list_entry(queue->next, struct sched_rt_entity, run_list); return next; } @@ -867,7 +849,7 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu) continue; if (next && next->prio < idx) continue; - list_for_each_entry(rt_se, array->squeue + idx, run_list) { + list_for_each_entry(rt_se, array->queue + idx, run_list) { struct task_struct *p = rt_task_of(rt_se); if (pick_rt_task(rq, p, cpu)) { next = p; @@ -1249,14 +1231,6 @@ static void set_cpus_allowed_rt(struct task_struct *p, } update_rt_migration(rq); - - if (unlikely(weight == 1 || p->rt.nr_cpus_allowed == 1)) - /* - * If either the new or old weight is a "1", we need - * to requeue to properly move between shared and - * exclusive queues. - */ - requeue_task_rt(rq, p); } p->cpus_allowed = *new_mask; -- cgit v1.2.3-70-g09d2 From 10b612f440a22a294e87ec7e8f03f9eea3338628 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 19 Jun 2008 14:22:27 +0200 Subject: sched: rt: fix the bandwidth contraint computations Signed-off-by: Peter Zijlstra Cc: "Daniel K." Signed-off-by: Ingo Molnar --- kernel/sched.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 5b307da827e..1f711a58a2b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -8419,7 +8419,7 @@ static unsigned long to_ratio(u64 period, u64 runtime) #ifdef CONFIG_CGROUP_SCHED static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) { - struct task_group *tgi, *parent = tg ? tg->parent : NULL; + struct task_group *tgi, *parent = tg->parent; unsigned long total = 0; if (!parent) { @@ -8443,7 +8443,7 @@ static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) } rcu_read_unlock(); - return total + to_ratio(period, runtime) < + return total + to_ratio(period, runtime) <= to_ratio(ktime_to_ns(parent->rt_bandwidth.rt_period), parent->rt_bandwidth.rt_runtime); } @@ -8560,10 +8560,15 @@ long sched_group_rt_period(struct task_group *tg) static int sched_rt_global_constraints(void) { + struct task_group *tg = &root_task_group; + u64 rt_runtime, rt_period; int ret = 0; + rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); + rt_runtime = tg->rt_bandwidth.rt_runtime; + mutex_lock(&rt_constraints_mutex); - if (!__rt_schedulable(NULL, 1, 0)) + if (!__rt_schedulable(tg, rt_period, rt_runtime)) ret = -EINVAL; mutex_unlock(&rt_constraints_mutex); -- cgit v1.2.3-70-g09d2 From 961ccddd59d627b89bd3dc284b6517833bbdf25d Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 23 Jun 2008 13:55:38 +1000 Subject: sched: add new API sched_setscheduler_nocheck: add a flag to control access checks Hidehiro Kawai noticed that sched_setscheduler() can fail in stop_machine: it calls sched_setscheduler() from insmod, which can have CAP_SYS_MODULE without CAP_SYS_NICE. Two cases could have failed, so are changed to sched_setscheduler_nocheck: kernel/softirq.c:cpu_callback() - CPU hotplug callback kernel/stop_machine.c:__stop_machine_run() - Called from various places, including modprobe() Signed-off-by: Rusty Russell Cc: Jeremy Fitzhardinge Cc: Hidehiro Kawai Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: sugita Cc: Satoshi OSHIMA Signed-off-by: Ingo Molnar --- include/linux/sched.h | 2 ++ kernel/sched.c | 48 ++++++++++++++++++++++++++++++++++++------------ kernel/softirq.c | 2 +- kernel/stop_machine.c | 2 +- 4 files changed, 40 insertions(+), 14 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index c5d3f847ca8..fe3b9b5d739 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1655,6 +1655,8 @@ extern int can_nice(const struct task_struct *p, const int nice); extern int task_curr(const struct task_struct *p); extern int idle_cpu(int cpu); extern int sched_setscheduler(struct task_struct *, int, struct sched_param *); +extern int sched_setscheduler_nocheck(struct task_struct *, int, + struct sched_param *); extern struct task_struct *idle_task(int cpu); extern struct task_struct *curr_task(int cpu); extern void set_curr_task(int cpu, struct task_struct *p); diff --git a/kernel/sched.c b/kernel/sched.c index b048ad8a11a..8d7c246ab86 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4746,16 +4746,8 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) set_load_weight(p); } -/** - * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. - * @p: the task in question. - * @policy: new policy. - * @param: structure containing the new RT priority. - * - * NOTE that the task may be already dead. - */ -int sched_setscheduler(struct task_struct *p, int policy, - struct sched_param *param) +static int __sched_setscheduler(struct task_struct *p, int policy, + struct sched_param *param, bool user) { int retval, oldprio, oldpolicy = -1, on_rq, running; unsigned long flags; @@ -4787,7 +4779,7 @@ recheck: /* * Allow unprivileged RT tasks to decrease priority: */ - if (!capable(CAP_SYS_NICE)) { + if (user && !capable(CAP_SYS_NICE)) { if (rt_policy(policy)) { unsigned long rlim_rtprio; @@ -4823,7 +4815,8 @@ recheck: * Do not allow realtime tasks into groups that have no runtime * assigned. */ - if (rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0) + if (user + && rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0) return -EPERM; #endif @@ -4872,8 +4865,39 @@ recheck: return 0; } + +/** + * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. + * @p: the task in question. + * @policy: new policy. + * @param: structure containing the new RT priority. + * + * NOTE that the task may be already dead. + */ +int sched_setscheduler(struct task_struct *p, int policy, + struct sched_param *param) +{ + return __sched_setscheduler(p, policy, param, true); +} EXPORT_SYMBOL_GPL(sched_setscheduler); +/** + * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. + * @p: the task in question. + * @policy: new policy. + * @param: structure containing the new RT priority. + * + * Just like sched_setscheduler, only don't bother checking if the + * current context has permission. For example, this is needed in + * stop_machine(): we create temporary high priority worker threads, + * but our caller might not have that capability. + */ +int sched_setscheduler_nocheck(struct task_struct *p, int policy, + struct sched_param *param) +{ + return __sched_setscheduler(p, policy, param, false); +} + static int do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) { diff --git a/kernel/softirq.c b/kernel/softirq.c index 36e06174004..afd9120c2fc 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -645,7 +645,7 @@ static int __cpuinit cpu_callback(struct notifier_block *nfb, p = per_cpu(ksoftirqd, hotcpu); per_cpu(ksoftirqd, hotcpu) = NULL; - sched_setscheduler(p, SCHED_FIFO, ¶m); + sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); kthread_stop(p); takeover_tasklets(hotcpu); break; diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index b7350bbfb07..ba9b2054ecb 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -187,7 +187,7 @@ struct task_struct *__stop_machine_run(int (*fn)(void *), void *data, struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; /* One high-prio thread per cpu. We'll do this one. */ - sched_setscheduler(p, SCHED_FIFO, ¶m); + sched_setscheduler_nocheck(p, SCHED_FIFO, ¶m); kthread_bind(p, cpu); wake_up_process(p); wait_for_completion(&smdata.done); -- cgit v1.2.3-70-g09d2 From a7be37ac8e1565e00880531f4e2aff421a21c803 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:11 +0200 Subject: sched: revert the revert of: weight calculations Try again.. initial commit: 8f1bc385cfbab474db6c27b5af1e439614f3025c revert: f9305d4a0968201b2818dbed0dc8cb0d4ee7aeb3 Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 9 ++--- kernel/sched_fair.c | 105 +++++++++++++++++++++++++++++++++--------------- kernel/sched_features.h | 1 + 3 files changed, 76 insertions(+), 39 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index c51d9fae8cd..f653af684fb 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1342,6 +1342,9 @@ static void __resched_task(struct task_struct *p, int tif_bit) */ #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) +/* + * delta *= weight / lw + */ static unsigned long calc_delta_mine(unsigned long delta_exec, unsigned long weight, struct load_weight *lw) @@ -1369,12 +1372,6 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight, return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); } -static inline unsigned long -calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) -{ - return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); -} - static inline void update_load_add(struct load_weight *lw, unsigned long inc) { lw->weight += inc; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 1fe4c65a817..496500988ce 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -333,6 +333,34 @@ int sched_nr_latency_handler(struct ctl_table *table, int write, } #endif +/* + * delta *= w / rw + */ +static inline unsigned long +calc_delta_weight(unsigned long delta, struct sched_entity *se) +{ + for_each_sched_entity(se) { + delta = calc_delta_mine(delta, + se->load.weight, &cfs_rq_of(se)->load); + } + + return delta; +} + +/* + * delta *= rw / w + */ +static inline unsigned long +calc_delta_fair(unsigned long delta, struct sched_entity *se) +{ + for_each_sched_entity(se) { + delta = calc_delta_mine(delta, + cfs_rq_of(se)->load.weight, &se->load); + } + + return delta; +} + /* * The idea is to set a period in which each task runs once. * @@ -362,47 +390,54 @@ static u64 __sched_period(unsigned long nr_running) */ static u64 sched_slice(struct cfs_rq *cfs_rq, struct sched_entity *se) { - u64 slice = __sched_period(cfs_rq->nr_running); - - for_each_sched_entity(se) { - cfs_rq = cfs_rq_of(se); - - slice *= se->load.weight; - do_div(slice, cfs_rq->load.weight); - } - - - return slice; + return calc_delta_weight(__sched_period(cfs_rq->nr_running), se); } /* * We calculate the vruntime slice of a to be inserted task * - * vs = s/w = p/rw + * vs = s*rw/w = p */ static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se) { unsigned long nr_running = cfs_rq->nr_running; - unsigned long weight; - u64 vslice; if (!se->on_rq) nr_running++; - vslice = __sched_period(nr_running); + return __sched_period(nr_running); +} + +/* + * The goal of calc_delta_asym() is to be asymmetrically around NICE_0_LOAD, in + * that it favours >=0 over <0. + * + * -20 | + * | + * 0 --------+------- + * .' + * 19 .' + * + */ +static unsigned long +calc_delta_asym(unsigned long delta, struct sched_entity *se) +{ + struct load_weight lw = { + .weight = NICE_0_LOAD, + .inv_weight = 1UL << (WMULT_SHIFT-NICE_0_SHIFT) + }; for_each_sched_entity(se) { - cfs_rq = cfs_rq_of(se); + struct load_weight *se_lw = &se->load; - weight = cfs_rq->load.weight; - if (!se->on_rq) - weight += se->load.weight; + if (se->load.weight < NICE_0_LOAD) + se_lw = &lw; - vslice *= NICE_0_LOAD; - do_div(vslice, weight); + delta = calc_delta_mine(delta, + cfs_rq_of(se)->load.weight, se_lw); } - return vslice; + return delta; } /* @@ -419,11 +454,7 @@ __update_curr(struct cfs_rq *cfs_rq, struct sched_entity *curr, curr->sum_exec_runtime += delta_exec; schedstat_add(cfs_rq, exec_clock, delta_exec); - delta_exec_weighted = delta_exec; - if (unlikely(curr->load.weight != NICE_0_LOAD)) { - delta_exec_weighted = calc_delta_fair(delta_exec_weighted, - &curr->load); - } + delta_exec_weighted = calc_delta_fair(delta_exec, curr); curr->vruntime += delta_exec_weighted; } @@ -609,8 +640,17 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) if (!initial) { /* sleeps upto a single latency don't count. */ - if (sched_feat(NEW_FAIR_SLEEPERS)) - vruntime -= sysctl_sched_latency; + if (sched_feat(NEW_FAIR_SLEEPERS)) { + unsigned long thresh = sysctl_sched_latency; + + /* + * convert the sleeper threshold into virtual time + */ + if (sched_feat(NORMALIZED_SLEEPER)) + thresh = calc_delta_fair(thresh, se); + + vruntime -= thresh; + } /* ensure we never gain time by being placed backwards. */ vruntime = max_vruntime(se->vruntime, vruntime); @@ -1111,11 +1151,10 @@ static unsigned long wakeup_gran(struct sched_entity *se) unsigned long gran = sysctl_sched_wakeup_granularity; /* - * More easily preempt - nice tasks, while not making - * it harder for + nice tasks. + * More easily preempt - nice tasks, while not making it harder for + * + nice tasks. */ - if (unlikely(se->load.weight > NICE_0_LOAD)) - gran = calc_delta_fair(gran, &se->load); + gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se); return gran; } diff --git a/kernel/sched_features.h b/kernel/sched_features.h index 62b39ca92eb..afa549166d8 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -1,4 +1,5 @@ SCHED_FEAT(NEW_FAIR_SLEEPERS, 1) +SCHED_FEAT(NORMALIZED_SLEEPER, 1) SCHED_FEAT(WAKEUP_PREEMPT, 1) SCHED_FEAT(START_DEBIT, 1) SCHED_FEAT(AFFINE_WAKEUPS, 1) -- cgit v1.2.3-70-g09d2 From c09595f63bb1909c5dc4dca288f4fe818561b5f3 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:14 +0200 Subject: sched: revert revert of: fair-group: SMP-nice for group scheduling Try again.. Initial commit: 18d95a2832c1392a2d63227a7a6d433cb9f2037e Revert: 6363ca57c76b7b83639ca8c83fc285fa26a7880e Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 + kernel/sched.c | 430 ++++++++++++++++++++++++++++++++++++++++++++++---- kernel/sched_debug.c | 5 + kernel/sched_fair.c | 124 +++++++++------ kernel/sched_rt.c | 4 + 5 files changed, 489 insertions(+), 75 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index eaf821072db..97a58b622ee 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -765,6 +765,7 @@ struct sched_domain { struct sched_domain *child; /* bottom domain must be null terminated */ struct sched_group *groups; /* the balancing groups of the domain */ cpumask_t span; /* span of all CPUs in this domain */ + int first_cpu; /* cache of the first cpu in this domain */ unsigned long min_interval; /* Minimum balance interval ms */ unsigned long max_interval; /* Maximum balance interval ms */ unsigned int busy_factor; /* less balancing by factor if busy */ diff --git a/kernel/sched.c b/kernel/sched.c index f653af684fb..874b6da1543 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -403,6 +403,43 @@ struct cfs_rq { */ struct list_head leaf_cfs_rq_list; struct task_group *tg; /* group that "owns" this runqueue */ + +#ifdef CONFIG_SMP + unsigned long task_weight; + unsigned long shares; + /* + * We need space to build a sched_domain wide view of the full task + * group tree, in order to avoid depending on dynamic memory allocation + * during the load balancing we place this in the per cpu task group + * hierarchy. This limits the load balancing to one instance per cpu, + * but more should not be needed anyway. + */ + struct aggregate_struct { + /* + * load = weight(cpus) * f(tg) + * + * Where f(tg) is the recursive weight fraction assigned to + * this group. + */ + unsigned long load; + + /* + * part of the group weight distributed to this span. + */ + unsigned long shares; + + /* + * The sum of all runqueue weights within this span. + */ + unsigned long rq_weight; + + /* + * Weight contributed by tasks; this is the part we can + * influence by moving tasks around. + */ + unsigned long task_weight; + } aggregate; +#endif #endif }; @@ -1484,6 +1521,326 @@ static unsigned long source_load(int cpu, int type); static unsigned long target_load(int cpu, int type); static unsigned long cpu_avg_load_per_task(int cpu); static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); + +#ifdef CONFIG_FAIR_GROUP_SCHED + +/* + * Group load balancing. + * + * We calculate a few balance domain wide aggregate numbers; load and weight. + * Given the pictures below, and assuming each item has equal weight: + * + * root 1 - thread + * / | \ A - group + * A 1 B + * /|\ / \ + * C 2 D 3 4 + * | | + * 5 6 + * + * load: + * A and B get 1/3-rd of the total load. C and D get 1/3-rd of A's 1/3-rd, + * which equals 1/9-th of the total load. + * + * shares: + * The weight of this group on the selected cpus. + * + * rq_weight: + * Direct sum of all the cpu's their rq weight, e.g. A would get 3 while + * B would get 2. + * + * task_weight: + * Part of the rq_weight contributed by tasks; all groups except B would + * get 1, B gets 2. + */ + +static inline struct aggregate_struct * +aggregate(struct task_group *tg, struct sched_domain *sd) +{ + return &tg->cfs_rq[sd->first_cpu]->aggregate; +} + +typedef void (*aggregate_func)(struct task_group *, struct sched_domain *); + +/* + * Iterate the full tree, calling @down when first entering a node and @up when + * leaving it for the final time. + */ +static +void aggregate_walk_tree(aggregate_func down, aggregate_func up, + struct sched_domain *sd) +{ + struct task_group *parent, *child; + + rcu_read_lock(); + parent = &root_task_group; +down: + (*down)(parent, sd); + list_for_each_entry_rcu(child, &parent->children, siblings) { + parent = child; + goto down; + +up: + continue; + } + (*up)(parent, sd); + + child = parent; + parent = parent->parent; + if (parent) + goto up; + rcu_read_unlock(); +} + +/* + * Calculate the aggregate runqueue weight. + */ +static +void aggregate_group_weight(struct task_group *tg, struct sched_domain *sd) +{ + unsigned long rq_weight = 0; + unsigned long task_weight = 0; + int i; + + for_each_cpu_mask(i, sd->span) { + rq_weight += tg->cfs_rq[i]->load.weight; + task_weight += tg->cfs_rq[i]->task_weight; + } + + aggregate(tg, sd)->rq_weight = rq_weight; + aggregate(tg, sd)->task_weight = task_weight; +} + +/* + * Compute the weight of this group on the given cpus. + */ +static +void aggregate_group_shares(struct task_group *tg, struct sched_domain *sd) +{ + unsigned long shares = 0; + int i; + + for_each_cpu_mask(i, sd->span) + shares += tg->cfs_rq[i]->shares; + + if ((!shares && aggregate(tg, sd)->rq_weight) || shares > tg->shares) + shares = tg->shares; + + aggregate(tg, sd)->shares = shares; +} + +/* + * Compute the load fraction assigned to this group, relies on the aggregate + * weight and this group's parent's load, i.e. top-down. + */ +static +void aggregate_group_load(struct task_group *tg, struct sched_domain *sd) +{ + unsigned long load; + + if (!tg->parent) { + int i; + + load = 0; + for_each_cpu_mask(i, sd->span) + load += cpu_rq(i)->load.weight; + + } else { + load = aggregate(tg->parent, sd)->load; + + /* + * shares is our weight in the parent's rq so + * shares/parent->rq_weight gives our fraction of the load + */ + load *= aggregate(tg, sd)->shares; + load /= aggregate(tg->parent, sd)->rq_weight + 1; + } + + aggregate(tg, sd)->load = load; +} + +static void __set_se_shares(struct sched_entity *se, unsigned long shares); + +/* + * Calculate and set the cpu's group shares. + */ +static void +__update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd, + int tcpu) +{ + int boost = 0; + unsigned long shares; + unsigned long rq_weight; + + if (!tg->se[tcpu]) + return; + + rq_weight = tg->cfs_rq[tcpu]->load.weight; + + /* + * If there are currently no tasks on the cpu pretend there is one of + * average load so that when a new task gets to run here it will not + * get delayed by group starvation. + */ + if (!rq_weight) { + boost = 1; + rq_weight = NICE_0_LOAD; + } + + /* + * \Sum shares * rq_weight + * shares = ----------------------- + * \Sum rq_weight + * + */ + shares = aggregate(tg, sd)->shares * rq_weight; + shares /= aggregate(tg, sd)->rq_weight + 1; + + /* + * record the actual number of shares, not the boosted amount. + */ + tg->cfs_rq[tcpu]->shares = boost ? 0 : shares; + + if (shares < MIN_SHARES) + shares = MIN_SHARES; + else if (shares > MAX_SHARES) + shares = MAX_SHARES; + + __set_se_shares(tg->se[tcpu], shares); +} + +/* + * Re-adjust the weights on the cpu the task came from and on the cpu the + * task went to. + */ +static void +__move_group_shares(struct task_group *tg, struct sched_domain *sd, + int scpu, int dcpu) +{ + unsigned long shares; + + shares = tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares; + + __update_group_shares_cpu(tg, sd, scpu); + __update_group_shares_cpu(tg, sd, dcpu); + + /* + * ensure we never loose shares due to rounding errors in the + * above redistribution. + */ + shares -= tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares; + if (shares) + tg->cfs_rq[dcpu]->shares += shares; +} + +/* + * Because changing a group's shares changes the weight of the super-group + * we need to walk up the tree and change all shares until we hit the root. + */ +static void +move_group_shares(struct task_group *tg, struct sched_domain *sd, + int scpu, int dcpu) +{ + while (tg) { + __move_group_shares(tg, sd, scpu, dcpu); + tg = tg->parent; + } +} + +static +void aggregate_group_set_shares(struct task_group *tg, struct sched_domain *sd) +{ + unsigned long shares = aggregate(tg, sd)->shares; + int i; + + for_each_cpu_mask(i, sd->span) { + struct rq *rq = cpu_rq(i); + unsigned long flags; + + spin_lock_irqsave(&rq->lock, flags); + __update_group_shares_cpu(tg, sd, i); + spin_unlock_irqrestore(&rq->lock, flags); + } + + aggregate_group_shares(tg, sd); + + /* + * ensure we never loose shares due to rounding errors in the + * above redistribution. + */ + shares -= aggregate(tg, sd)->shares; + if (shares) { + tg->cfs_rq[sd->first_cpu]->shares += shares; + aggregate(tg, sd)->shares += shares; + } +} + +/* + * Calculate the accumulative weight and recursive load of each task group + * while walking down the tree. + */ +static +void aggregate_get_down(struct task_group *tg, struct sched_domain *sd) +{ + aggregate_group_weight(tg, sd); + aggregate_group_shares(tg, sd); + aggregate_group_load(tg, sd); +} + +/* + * Rebalance the cpu shares while walking back up the tree. + */ +static +void aggregate_get_up(struct task_group *tg, struct sched_domain *sd) +{ + aggregate_group_set_shares(tg, sd); +} + +static DEFINE_PER_CPU(spinlock_t, aggregate_lock); + +static void __init init_aggregate(void) +{ + int i; + + for_each_possible_cpu(i) + spin_lock_init(&per_cpu(aggregate_lock, i)); +} + +static int get_aggregate(struct sched_domain *sd) +{ + if (!spin_trylock(&per_cpu(aggregate_lock, sd->first_cpu))) + return 0; + + aggregate_walk_tree(aggregate_get_down, aggregate_get_up, sd); + return 1; +} + +static void put_aggregate(struct sched_domain *sd) +{ + spin_unlock(&per_cpu(aggregate_lock, sd->first_cpu)); +} + +static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) +{ + cfs_rq->shares = shares; +} + +#else + +static inline void init_aggregate(void) +{ +} + +static inline int get_aggregate(struct sched_domain *sd) +{ + return 0; +} + +static inline void put_aggregate(struct sched_domain *sd) +{ +} +#endif + #endif #include "sched_stats.h" @@ -1498,26 +1855,14 @@ static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); #define for_each_class(class) \ for (class = sched_class_highest; class; class = class->next) -static inline void inc_load(struct rq *rq, const struct task_struct *p) -{ - update_load_add(&rq->load, p->se.load.weight); -} - -static inline void dec_load(struct rq *rq, const struct task_struct *p) -{ - update_load_sub(&rq->load, p->se.load.weight); -} - -static void inc_nr_running(struct task_struct *p, struct rq *rq) +static void inc_nr_running(struct rq *rq) { rq->nr_running++; - inc_load(rq, p); } -static void dec_nr_running(struct task_struct *p, struct rq *rq) +static void dec_nr_running(struct rq *rq) { rq->nr_running--; - dec_load(rq, p); } static void set_load_weight(struct task_struct *p) @@ -1609,7 +1954,7 @@ static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) rq->nr_uninterruptible--; enqueue_task(rq, p, wakeup); - inc_nr_running(p, rq); + inc_nr_running(rq); } /* @@ -1621,7 +1966,7 @@ static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) rq->nr_uninterruptible++; dequeue_task(rq, p, sleep); - dec_nr_running(p, rq); + dec_nr_running(rq); } /** @@ -2274,7 +2619,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) * management (if any): */ p->sched_class->task_new(rq, p); - inc_nr_running(p, rq); + inc_nr_running(rq); } check_preempt_curr(rq, p); #ifdef CONFIG_SMP @@ -3265,9 +3610,12 @@ static int load_balance(int this_cpu, struct rq *this_rq, unsigned long imbalance; struct rq *busiest; unsigned long flags; + int unlock_aggregate; cpus_setall(*cpus); + unlock_aggregate = get_aggregate(sd); + /* * When power savings policy is enabled for the parent domain, idle * sibling can pick up load irrespective of busy siblings. In this case, @@ -3383,8 +3731,9 @@ redo: if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - return ld_moved; + ld_moved = -1; + + goto out; out_balanced: schedstat_inc(sd, lb_balanced[idle]); @@ -3399,8 +3748,13 @@ out_one_pinned: if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - return 0; + ld_moved = -1; + else + ld_moved = 0; +out: + if (unlock_aggregate) + put_aggregate(sd); + return ld_moved; } /* @@ -4588,10 +4942,8 @@ void set_user_nice(struct task_struct *p, long nice) goto out_unlock; } on_rq = p->se.on_rq; - if (on_rq) { + if (on_rq) dequeue_task(rq, p, 0); - dec_load(rq, p); - } p->static_prio = NICE_TO_PRIO(nice); set_load_weight(p); @@ -4601,7 +4953,6 @@ void set_user_nice(struct task_struct *p, long nice) if (on_rq) { enqueue_task(rq, p, 0); - inc_load(rq, p); /* * If the task increased its priority or is running and * lowered its priority, then reschedule its CPU: @@ -7016,6 +7367,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, ALLNODES); set_domain_attribute(sd, attr); sd->span = *cpu_map; + sd->first_cpu = first_cpu(sd->span); cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask); p = sd; sd_allnodes = 1; @@ -7026,6 +7378,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, NODE); set_domain_attribute(sd, attr); sched_domain_node_span(cpu_to_node(i), &sd->span); + sd->first_cpu = first_cpu(sd->span); sd->parent = p; if (p) p->child = sd; @@ -7037,6 +7390,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, CPU); set_domain_attribute(sd, attr); sd->span = *nodemask; + sd->first_cpu = first_cpu(sd->span); sd->parent = p; if (p) p->child = sd; @@ -7048,6 +7402,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, MC); set_domain_attribute(sd, attr); sd->span = cpu_coregroup_map(i); + sd->first_cpu = first_cpu(sd->span); cpus_and(sd->span, sd->span, *cpu_map); sd->parent = p; p->child = sd; @@ -7060,6 +7415,7 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, SIBLING); set_domain_attribute(sd, attr); sd->span = per_cpu(cpu_sibling_map, i); + sd->first_cpu = first_cpu(sd->span); cpus_and(sd->span, sd->span, *cpu_map); sd->parent = p; p->child = sd; @@ -7757,6 +8113,7 @@ void __init sched_init(void) } #ifdef CONFIG_SMP + init_aggregate(); init_defrootdomain(); #endif @@ -8322,14 +8679,11 @@ void sched_move_task(struct task_struct *tsk) #endif /* CONFIG_GROUP_SCHED */ #ifdef CONFIG_FAIR_GROUP_SCHED -static void set_se_shares(struct sched_entity *se, unsigned long shares) +static void __set_se_shares(struct sched_entity *se, unsigned long shares) { struct cfs_rq *cfs_rq = se->cfs_rq; - struct rq *rq = cfs_rq->rq; int on_rq; - spin_lock_irq(&rq->lock); - on_rq = se->on_rq; if (on_rq) dequeue_entity(cfs_rq, se, 0); @@ -8339,8 +8693,17 @@ static void set_se_shares(struct sched_entity *se, unsigned long shares) if (on_rq) enqueue_entity(cfs_rq, se, 0); +} - spin_unlock_irq(&rq->lock); +static void set_se_shares(struct sched_entity *se, unsigned long shares) +{ + struct cfs_rq *cfs_rq = se->cfs_rq; + struct rq *rq = cfs_rq->rq; + unsigned long flags; + + spin_lock_irqsave(&rq->lock, flags); + __set_se_shares(se, shares); + spin_unlock_irqrestore(&rq->lock, flags); } static DEFINE_MUTEX(shares_mutex); @@ -8379,8 +8742,13 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) * w/o tripping rebalance_share or load_balance_fair. */ tg->shares = shares; - for_each_possible_cpu(i) + for_each_possible_cpu(i) { + /* + * force a rebalance + */ + cfs_rq_set_shares(tg->cfs_rq[i], 0); set_se_shares(tg->se[i], shares); + } /* * Enable load balance activity on this group, by inserting it back on diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index 8e077b9c91c..04394ccac88 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -167,6 +167,11 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq) #endif SEQ_printf(m, " .%-30s: %ld\n", "nr_spread_over", cfs_rq->nr_spread_over); +#ifdef CONFIG_FAIR_GROUP_SCHED +#ifdef CONFIG_SMP + SEQ_printf(m, " .%-30s: %lu\n", "shares", cfs_rq->shares); +#endif +#endif } void print_rt_rq(struct seq_file *m, int cpu, struct rt_rq *rt_rq) diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 2e197b8e43f..183388c4dea 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -567,10 +567,27 @@ update_stats_curr_start(struct cfs_rq *cfs_rq, struct sched_entity *se) * Scheduling class queueing methods: */ +#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED +static void +add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) +{ + cfs_rq->task_weight += weight; +} +#else +static inline void +add_cfs_task_weight(struct cfs_rq *cfs_rq, unsigned long weight) +{ +} +#endif + static void account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se) { update_load_add(&cfs_rq->load, se->load.weight); + if (!parent_entity(se)) + inc_cpu_load(rq_of(cfs_rq), se->load.weight); + if (entity_is_task(se)) + add_cfs_task_weight(cfs_rq, se->load.weight); cfs_rq->nr_running++; se->on_rq = 1; list_add(&se->group_node, &cfs_rq->tasks); @@ -580,6 +597,10 @@ static void account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se) { update_load_sub(&cfs_rq->load, se->load.weight); + if (!parent_entity(se)) + dec_cpu_load(rq_of(cfs_rq), se->load.weight); + if (entity_is_task(se)) + add_cfs_task_weight(cfs_rq, -se->load.weight); cfs_rq->nr_running--; se->on_rq = 0; list_del_init(&se->group_node); @@ -1372,75 +1393,90 @@ static struct task_struct *load_balance_next_fair(void *arg) return __load_balance_iterator(cfs_rq, cfs_rq->balance_iterator); } -#ifdef CONFIG_FAIR_GROUP_SCHED -static int cfs_rq_best_prio(struct cfs_rq *cfs_rq) +static unsigned long +__load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, struct sched_domain *sd, + enum cpu_idle_type idle, int *all_pinned, int *this_best_prio, + struct cfs_rq *cfs_rq) { - struct sched_entity *curr; - struct task_struct *p; - - if (!cfs_rq->nr_running || !first_fair(cfs_rq)) - return MAX_PRIO; - - curr = cfs_rq->curr; - if (!curr) - curr = __pick_next_entity(cfs_rq); + struct rq_iterator cfs_rq_iterator; - p = task_of(curr); + cfs_rq_iterator.start = load_balance_start_fair; + cfs_rq_iterator.next = load_balance_next_fair; + cfs_rq_iterator.arg = cfs_rq; - return p->prio; + return balance_tasks(this_rq, this_cpu, busiest, + max_load_move, sd, idle, all_pinned, + this_best_prio, &cfs_rq_iterator); } -#endif +#ifdef CONFIG_FAIR_GROUP_SCHED static unsigned long load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, unsigned long max_load_move, struct sched_domain *sd, enum cpu_idle_type idle, int *all_pinned, int *this_best_prio) { - struct cfs_rq *busy_cfs_rq; long rem_load_move = max_load_move; - struct rq_iterator cfs_rq_iterator; - - cfs_rq_iterator.start = load_balance_start_fair; - cfs_rq_iterator.next = load_balance_next_fair; + int busiest_cpu = cpu_of(busiest); + struct task_group *tg; - for_each_leaf_cfs_rq(busiest, busy_cfs_rq) { -#ifdef CONFIG_FAIR_GROUP_SCHED - struct cfs_rq *this_cfs_rq; + rcu_read_lock(); + list_for_each_entry(tg, &task_groups, list) { long imbalance; - unsigned long maxload; + unsigned long this_weight, busiest_weight; + long rem_load, max_load, moved_load; + + /* + * empty group + */ + if (!aggregate(tg, sd)->task_weight) + continue; + + rem_load = rem_load_move * aggregate(tg, sd)->rq_weight; + rem_load /= aggregate(tg, sd)->load + 1; + + this_weight = tg->cfs_rq[this_cpu]->task_weight; + busiest_weight = tg->cfs_rq[busiest_cpu]->task_weight; - this_cfs_rq = cpu_cfs_rq(busy_cfs_rq, this_cpu); + imbalance = (busiest_weight - this_weight) / 2; - imbalance = busy_cfs_rq->load.weight - this_cfs_rq->load.weight; - /* Don't pull if this_cfs_rq has more load than busy_cfs_rq */ - if (imbalance <= 0) + if (imbalance < 0) + imbalance = busiest_weight; + + max_load = max(rem_load, imbalance); + moved_load = __load_balance_fair(this_rq, this_cpu, busiest, + max_load, sd, idle, all_pinned, this_best_prio, + tg->cfs_rq[busiest_cpu]); + + if (!moved_load) continue; - /* Don't pull more than imbalance/2 */ - imbalance /= 2; - maxload = min(rem_load_move, imbalance); + move_group_shares(tg, sd, busiest_cpu, this_cpu); - *this_best_prio = cfs_rq_best_prio(this_cfs_rq); -#else -# define maxload rem_load_move -#endif - /* - * pass busy_cfs_rq argument into - * load_balance_[start|next]_fair iterators - */ - cfs_rq_iterator.arg = busy_cfs_rq; - rem_load_move -= balance_tasks(this_rq, this_cpu, busiest, - maxload, sd, idle, all_pinned, - this_best_prio, - &cfs_rq_iterator); + moved_load *= aggregate(tg, sd)->load; + moved_load /= aggregate(tg, sd)->rq_weight + 1; - if (rem_load_move <= 0) + rem_load_move -= moved_load; + if (rem_load_move < 0) break; } + rcu_read_unlock(); return max_load_move - rem_load_move; } +#else +static unsigned long +load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_load_move, + struct sched_domain *sd, enum cpu_idle_type idle, + int *all_pinned, int *this_best_prio) +{ + return __load_balance_fair(this_rq, this_cpu, busiest, + max_load_move, sd, idle, all_pinned, + this_best_prio, &busiest->cfs); +} +#endif static int move_one_task_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 6b4a6b5a416..765932d0399 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -670,6 +670,8 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) rt_se->timeout = 0; enqueue_rt_entity(rt_se); + + inc_cpu_load(rq, p->se.load.weight); } static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) @@ -678,6 +680,8 @@ static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) update_curr_rt(rq); dequeue_rt_entity(rt_se); + + dec_cpu_load(rq, p->se.load.weight); } /* -- cgit v1.2.3-70-g09d2 From 76a2a6ee8a0660a29127f05989ac59ae1ce865fa Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:15 +0200 Subject: sched: sched_clock_cpu() based cpu_clock() with sched_clock_cpu() being reasonably in sync between cpus (max 1 jiffy difference) use this to provide cpu_clock(). Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 76 ---------------------------------------------------- kernel/sched_clock.c | 12 +++++++++ 2 files changed, 12 insertions(+), 76 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 874b6da1543..eb3454c410f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -818,82 +818,6 @@ static inline u64 global_rt_runtime(void) return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC; } -unsigned long long time_sync_thresh = 100000; - -static DEFINE_PER_CPU(unsigned long long, time_offset); -static DEFINE_PER_CPU(unsigned long long, prev_cpu_time); - -/* - * Global lock which we take every now and then to synchronize - * the CPUs time. This method is not warp-safe, but it's good - * enough to synchronize slowly diverging time sources and thus - * it's good enough for tracing: - */ -static DEFINE_SPINLOCK(time_sync_lock); -static unsigned long long prev_global_time; - -static unsigned long long __sync_cpu_clock(unsigned long long time, int cpu) -{ - /* - * We want this inlined, to not get tracer function calls - * in this critical section: - */ - spin_acquire(&time_sync_lock.dep_map, 0, 0, _THIS_IP_); - __raw_spin_lock(&time_sync_lock.raw_lock); - - if (time < prev_global_time) { - per_cpu(time_offset, cpu) += prev_global_time - time; - time = prev_global_time; - } else { - prev_global_time = time; - } - - __raw_spin_unlock(&time_sync_lock.raw_lock); - spin_release(&time_sync_lock.dep_map, 1, _THIS_IP_); - - return time; -} - -static unsigned long long __cpu_clock(int cpu) -{ - unsigned long long now; - - /* - * Only call sched_clock() if the scheduler has already been - * initialized (some code might call cpu_clock() very early): - */ - if (unlikely(!scheduler_running)) - return 0; - - now = sched_clock_cpu(cpu); - - return now; -} - -/* - * For kernel-internal use: high-speed (but slightly incorrect) per-cpu - * clock constructed from sched_clock(): - */ -unsigned long long cpu_clock(int cpu) -{ - unsigned long long prev_cpu_time, time, delta_time; - unsigned long flags; - - local_irq_save(flags); - prev_cpu_time = per_cpu(prev_cpu_time, cpu); - time = __cpu_clock(cpu) + per_cpu(time_offset, cpu); - delta_time = time-prev_cpu_time; - - if (unlikely(delta_time > time_sync_thresh)) { - time = __sync_cpu_clock(time, cpu); - per_cpu(prev_cpu_time, cpu) = time; - } - local_irq_restore(flags); - - return time; -} -EXPORT_SYMBOL_GPL(cpu_clock); - #ifndef prepare_arch_switch # define prepare_arch_switch(next) do { } while (0) #endif diff --git a/kernel/sched_clock.c b/kernel/sched_clock.c index ce05271219a..3c696db5945 100644 --- a/kernel/sched_clock.c +++ b/kernel/sched_clock.c @@ -244,3 +244,15 @@ unsigned long long __attribute__((weak)) sched_clock(void) { return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); } + +unsigned long long cpu_clock(int cpu) +{ + unsigned long long clock; + unsigned long flags; + + raw_local_irq_save(flags); + clock = sched_clock_cpu(cpu); + raw_local_irq_restore(flags); + + return clock; +} -- cgit v1.2.3-70-g09d2 From 103638d95ba5b0c53c8d9c0cb581156ccc8513ee Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:16 +0200 Subject: sched: fix wakeup granularity and buddy granularity Uncouple buddy selection from wakeup granularity. The initial idea was that buddies could run ahead as far as a normal task can - do this by measuring a pair 'slice' just as we do for a normal task. This means we can drop the wakeup_granularity back to 5ms. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 + kernel/sched_fair.c | 15 +++++++-------- 2 files changed, 8 insertions(+), 8 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index eb3454c410f..7d282c52bd4 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -375,6 +375,7 @@ struct cfs_rq { u64 exec_clock; u64 min_vruntime; + u64 pair_start; struct rb_root tasks_timeline; struct rb_node *rb_leftmost; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 183388c4dea..509092af033 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -63,13 +63,13 @@ unsigned int __read_mostly sysctl_sched_compat_yield; /* * SCHED_OTHER wake-up granularity. - * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds) + * (default: 5 msec * (1 + ilog(ncpus)), units: nanoseconds) * * This option delays the preemption effects of decoupled workloads * and reduces their over-scheduling. Synchronous workloads will still * have immediate wakeup/sleep latencies. */ -unsigned int sysctl_sched_wakeup_granularity = 10000000UL; +unsigned int sysctl_sched_wakeup_granularity = 5000000UL; const_debug unsigned int sysctl_sched_migration_cost = 500000UL; @@ -813,17 +813,16 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) se->prev_sum_exec_runtime = se->sum_exec_runtime; } -static int -wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se); - static struct sched_entity * pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se) { - if (!cfs_rq->next) - return se; + struct rq *rq = rq_of(cfs_rq); + u64 pair_slice = rq->clock - cfs_rq->pair_start; - if (wakeup_preempt_entity(cfs_rq->next, se) != 0) + if (!cfs_rq->next || pair_slice > sched_slice(cfs_rq, cfs_rq->next)) { + cfs_rq->pair_start = rq->clock; return se; + } return cfs_rq->next; } -- cgit v1.2.3-70-g09d2 From b6a86c746f5b708012809958462234d19e9c8177 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:18 +0200 Subject: sched: fix sched_domain aggregation Keeping the aggregate on the first cpu of the sched domain has two problems: - it could collide between different sched domains on different cpus - it could slow things down because of the remote accesses Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- include/linux/sched.h | 1 - kernel/sched.c | 113 ++++++++++++++++++++++++-------------------------- kernel/sched_fair.c | 12 +++--- 3 files changed, 60 insertions(+), 66 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index 97a58b622ee..eaf821072db 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -765,7 +765,6 @@ struct sched_domain { struct sched_domain *child; /* bottom domain must be null terminated */ struct sched_group *groups; /* the balancing groups of the domain */ cpumask_t span; /* span of all CPUs in this domain */ - int first_cpu; /* cache of the first cpu in this domain */ unsigned long min_interval; /* Minimum balance interval ms */ unsigned long max_interval; /* Maximum balance interval ms */ unsigned int busy_factor; /* less balancing by factor if busy */ diff --git a/kernel/sched.c b/kernel/sched.c index 7d282c52bd4..160d3c209b8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1480,12 +1480,12 @@ static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); */ static inline struct aggregate_struct * -aggregate(struct task_group *tg, struct sched_domain *sd) +aggregate(struct task_group *tg, int cpu) { - return &tg->cfs_rq[sd->first_cpu]->aggregate; + return &tg->cfs_rq[cpu]->aggregate; } -typedef void (*aggregate_func)(struct task_group *, struct sched_domain *); +typedef void (*aggregate_func)(struct task_group *, int, struct sched_domain *); /* * Iterate the full tree, calling @down when first entering a node and @up when @@ -1493,14 +1493,14 @@ typedef void (*aggregate_func)(struct task_group *, struct sched_domain *); */ static void aggregate_walk_tree(aggregate_func down, aggregate_func up, - struct sched_domain *sd) + int cpu, struct sched_domain *sd) { struct task_group *parent, *child; rcu_read_lock(); parent = &root_task_group; down: - (*down)(parent, sd); + (*down)(parent, cpu, sd); list_for_each_entry_rcu(child, &parent->children, siblings) { parent = child; goto down; @@ -1508,7 +1508,7 @@ down: up: continue; } - (*up)(parent, sd); + (*up)(parent, cpu, sd); child = parent; parent = parent->parent; @@ -1520,8 +1520,8 @@ up: /* * Calculate the aggregate runqueue weight. */ -static -void aggregate_group_weight(struct task_group *tg, struct sched_domain *sd) +static void +aggregate_group_weight(struct task_group *tg, int cpu, struct sched_domain *sd) { unsigned long rq_weight = 0; unsigned long task_weight = 0; @@ -1532,15 +1532,15 @@ void aggregate_group_weight(struct task_group *tg, struct sched_domain *sd) task_weight += tg->cfs_rq[i]->task_weight; } - aggregate(tg, sd)->rq_weight = rq_weight; - aggregate(tg, sd)->task_weight = task_weight; + aggregate(tg, cpu)->rq_weight = rq_weight; + aggregate(tg, cpu)->task_weight = task_weight; } /* * Compute the weight of this group on the given cpus. */ -static -void aggregate_group_shares(struct task_group *tg, struct sched_domain *sd) +static void +aggregate_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd) { unsigned long shares = 0; int i; @@ -1548,18 +1548,18 @@ void aggregate_group_shares(struct task_group *tg, struct sched_domain *sd) for_each_cpu_mask(i, sd->span) shares += tg->cfs_rq[i]->shares; - if ((!shares && aggregate(tg, sd)->rq_weight) || shares > tg->shares) + if ((!shares && aggregate(tg, cpu)->rq_weight) || shares > tg->shares) shares = tg->shares; - aggregate(tg, sd)->shares = shares; + aggregate(tg, cpu)->shares = shares; } /* * Compute the load fraction assigned to this group, relies on the aggregate * weight and this group's parent's load, i.e. top-down. */ -static -void aggregate_group_load(struct task_group *tg, struct sched_domain *sd) +static void +aggregate_group_load(struct task_group *tg, int cpu, struct sched_domain *sd) { unsigned long load; @@ -1571,17 +1571,17 @@ void aggregate_group_load(struct task_group *tg, struct sched_domain *sd) load += cpu_rq(i)->load.weight; } else { - load = aggregate(tg->parent, sd)->load; + load = aggregate(tg->parent, cpu)->load; /* * shares is our weight in the parent's rq so * shares/parent->rq_weight gives our fraction of the load */ - load *= aggregate(tg, sd)->shares; - load /= aggregate(tg->parent, sd)->rq_weight + 1; + load *= aggregate(tg, cpu)->shares; + load /= aggregate(tg->parent, cpu)->rq_weight + 1; } - aggregate(tg, sd)->load = load; + aggregate(tg, cpu)->load = load; } static void __set_se_shares(struct sched_entity *se, unsigned long shares); @@ -1590,8 +1590,8 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares); * Calculate and set the cpu's group shares. */ static void -__update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd, - int tcpu) +__update_group_shares_cpu(struct task_group *tg, int cpu, + struct sched_domain *sd, int tcpu) { int boost = 0; unsigned long shares; @@ -1618,8 +1618,8 @@ __update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd, * \Sum rq_weight * */ - shares = aggregate(tg, sd)->shares * rq_weight; - shares /= aggregate(tg, sd)->rq_weight + 1; + shares = aggregate(tg, cpu)->shares * rq_weight; + shares /= aggregate(tg, cpu)->rq_weight + 1; /* * record the actual number of shares, not the boosted amount. @@ -1639,15 +1639,15 @@ __update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd, * task went to. */ static void -__move_group_shares(struct task_group *tg, struct sched_domain *sd, +__move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, int scpu, int dcpu) { unsigned long shares; shares = tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares; - __update_group_shares_cpu(tg, sd, scpu); - __update_group_shares_cpu(tg, sd, dcpu); + __update_group_shares_cpu(tg, cpu, sd, scpu); + __update_group_shares_cpu(tg, cpu, sd, dcpu); /* * ensure we never loose shares due to rounding errors in the @@ -1663,19 +1663,19 @@ __move_group_shares(struct task_group *tg, struct sched_domain *sd, * we need to walk up the tree and change all shares until we hit the root. */ static void -move_group_shares(struct task_group *tg, struct sched_domain *sd, +move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, int scpu, int dcpu) { while (tg) { - __move_group_shares(tg, sd, scpu, dcpu); + __move_group_shares(tg, cpu, sd, scpu, dcpu); tg = tg->parent; } } -static -void aggregate_group_set_shares(struct task_group *tg, struct sched_domain *sd) +static void +aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain *sd) { - unsigned long shares = aggregate(tg, sd)->shares; + unsigned long shares = aggregate(tg, cpu)->shares; int i; for_each_cpu_mask(i, sd->span) { @@ -1683,20 +1683,20 @@ void aggregate_group_set_shares(struct task_group *tg, struct sched_domain *sd) unsigned long flags; spin_lock_irqsave(&rq->lock, flags); - __update_group_shares_cpu(tg, sd, i); + __update_group_shares_cpu(tg, cpu, sd, i); spin_unlock_irqrestore(&rq->lock, flags); } - aggregate_group_shares(tg, sd); + aggregate_group_shares(tg, cpu, sd); /* * ensure we never loose shares due to rounding errors in the * above redistribution. */ - shares -= aggregate(tg, sd)->shares; + shares -= aggregate(tg, cpu)->shares; if (shares) { - tg->cfs_rq[sd->first_cpu]->shares += shares; - aggregate(tg, sd)->shares += shares; + tg->cfs_rq[cpu]->shares += shares; + aggregate(tg, cpu)->shares += shares; } } @@ -1704,21 +1704,21 @@ void aggregate_group_set_shares(struct task_group *tg, struct sched_domain *sd) * Calculate the accumulative weight and recursive load of each task group * while walking down the tree. */ -static -void aggregate_get_down(struct task_group *tg, struct sched_domain *sd) +static void +aggregate_get_down(struct task_group *tg, int cpu, struct sched_domain *sd) { - aggregate_group_weight(tg, sd); - aggregate_group_shares(tg, sd); - aggregate_group_load(tg, sd); + aggregate_group_weight(tg, cpu, sd); + aggregate_group_shares(tg, cpu, sd); + aggregate_group_load(tg, cpu, sd); } /* * Rebalance the cpu shares while walking back up the tree. */ -static -void aggregate_get_up(struct task_group *tg, struct sched_domain *sd) +static void +aggregate_get_up(struct task_group *tg, int cpu, struct sched_domain *sd) { - aggregate_group_set_shares(tg, sd); + aggregate_group_set_shares(tg, cpu, sd); } static DEFINE_PER_CPU(spinlock_t, aggregate_lock); @@ -1731,18 +1731,18 @@ static void __init init_aggregate(void) spin_lock_init(&per_cpu(aggregate_lock, i)); } -static int get_aggregate(struct sched_domain *sd) +static int get_aggregate(int cpu, struct sched_domain *sd) { - if (!spin_trylock(&per_cpu(aggregate_lock, sd->first_cpu))) + if (!spin_trylock(&per_cpu(aggregate_lock, cpu))) return 0; - aggregate_walk_tree(aggregate_get_down, aggregate_get_up, sd); + aggregate_walk_tree(aggregate_get_down, aggregate_get_up, cpu, sd); return 1; } -static void put_aggregate(struct sched_domain *sd) +static void put_aggregate(int cpu, struct sched_domain *sd) { - spin_unlock(&per_cpu(aggregate_lock, sd->first_cpu)); + spin_unlock(&per_cpu(aggregate_lock, cpu)); } static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) @@ -1756,12 +1756,12 @@ static inline void init_aggregate(void) { } -static inline int get_aggregate(struct sched_domain *sd) +static inline int get_aggregate(int cpu, struct sched_domain *sd) { return 0; } -static inline void put_aggregate(struct sched_domain *sd) +static inline void put_aggregate(int cpu, struct sched_domain *sd) { } #endif @@ -3539,7 +3539,7 @@ static int load_balance(int this_cpu, struct rq *this_rq, cpus_setall(*cpus); - unlock_aggregate = get_aggregate(sd); + unlock_aggregate = get_aggregate(this_cpu, sd); /* * When power savings policy is enabled for the parent domain, idle @@ -3678,7 +3678,7 @@ out_one_pinned: ld_moved = 0; out: if (unlock_aggregate) - put_aggregate(sd); + put_aggregate(this_cpu, sd); return ld_moved; } @@ -7292,7 +7292,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, ALLNODES); set_domain_attribute(sd, attr); sd->span = *cpu_map; - sd->first_cpu = first_cpu(sd->span); cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask); p = sd; sd_allnodes = 1; @@ -7303,7 +7302,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, NODE); set_domain_attribute(sd, attr); sched_domain_node_span(cpu_to_node(i), &sd->span); - sd->first_cpu = first_cpu(sd->span); sd->parent = p; if (p) p->child = sd; @@ -7315,7 +7313,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, CPU); set_domain_attribute(sd, attr); sd->span = *nodemask; - sd->first_cpu = first_cpu(sd->span); sd->parent = p; if (p) p->child = sd; @@ -7327,7 +7324,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, MC); set_domain_attribute(sd, attr); sd->span = cpu_coregroup_map(i); - sd->first_cpu = first_cpu(sd->span); cpus_and(sd->span, sd->span, *cpu_map); sd->parent = p; p->child = sd; @@ -7340,7 +7336,6 @@ static int __build_sched_domains(const cpumask_t *cpu_map, SD_INIT(sd, SIBLING); set_domain_attribute(sd, attr); sd->span = per_cpu(cpu_sibling_map, i); - sd->first_cpu = first_cpu(sd->span); cpus_and(sd->span, sd->span, *cpu_map); sd->parent = p; p->child = sd; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 509092af033..40cf24ab4de 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1429,11 +1429,11 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, /* * empty group */ - if (!aggregate(tg, sd)->task_weight) + if (!aggregate(tg, this_cpu)->task_weight) continue; - rem_load = rem_load_move * aggregate(tg, sd)->rq_weight; - rem_load /= aggregate(tg, sd)->load + 1; + rem_load = rem_load_move * aggregate(tg, this_cpu)->rq_weight; + rem_load /= aggregate(tg, this_cpu)->load + 1; this_weight = tg->cfs_rq[this_cpu]->task_weight; busiest_weight = tg->cfs_rq[busiest_cpu]->task_weight; @@ -1451,10 +1451,10 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, if (!moved_load) continue; - move_group_shares(tg, sd, busiest_cpu, this_cpu); + move_group_shares(tg, this_cpu, sd, busiest_cpu, this_cpu); - moved_load *= aggregate(tg, sd)->load; - moved_load /= aggregate(tg, sd)->rq_weight + 1; + moved_load *= aggregate(tg, this_cpu)->load; + moved_load /= aggregate(tg, this_cpu)->rq_weight + 1; rem_load_move -= moved_load; if (rem_load_move < 0) -- cgit v1.2.3-70-g09d2 From 4d8d595dfa69e1c807bf928f364668a7f30da5dc Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:19 +0200 Subject: sched: update aggregate when holding the RQs It was observed that in __update_group_shares_cpu() rq_weight > aggregate()->rq_weight This is caused by forks/wakeups in between the initial aggregate pass and locking of the RQs for load balance. To avoid this situation partially re-do the aggregation once we have the RQs locked (which avoids new tasks from appearing). Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 160d3c209b8..dae20199dc9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1721,6 +1721,11 @@ aggregate_get_up(struct task_group *tg, int cpu, struct sched_domain *sd) aggregate_group_set_shares(tg, cpu, sd); } +static void +aggregate_get_nop(struct task_group *tg, int cpu, struct sched_domain *sd) +{ +} + static DEFINE_PER_CPU(spinlock_t, aggregate_lock); static void __init init_aggregate(void) @@ -1740,6 +1745,11 @@ static int get_aggregate(int cpu, struct sched_domain *sd) return 1; } +static void update_aggregate(int cpu, struct sched_domain *sd) +{ + aggregate_walk_tree(aggregate_get_down, aggregate_get_nop, cpu, sd); +} + static void put_aggregate(int cpu, struct sched_domain *sd) { spin_unlock(&per_cpu(aggregate_lock, cpu)); @@ -1761,6 +1771,10 @@ static inline int get_aggregate(int cpu, struct sched_domain *sd) return 0; } +static inline void update_aggregate(int cpu, struct sched_domain *sd) +{ +} + static inline void put_aggregate(int cpu, struct sched_domain *sd) { } @@ -2192,6 +2206,12 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) int load_idx = sd->forkexec_idx; int imbalance = 100 + (sd->imbalance_pct-100)/2; + /* + * now that we have both rqs locked the rq weight won't change + * anymore - so update the stats. + */ + update_aggregate(this_cpu, sd); + do { unsigned long load, avg_load; int local_group; -- cgit v1.2.3-70-g09d2 From d3f40dbab954d83383b6a516582d5c09cc216dcc Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:21 +0200 Subject: sched: dont micro manage share losses We used to try and contain the loss of 'shares' by playing arithmetic games. Replace that by noticing that at the top sched_domain we'll always have the full weight in shares to distribute. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 26 +++----------------------- 1 file changed, 3 insertions(+), 23 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index dae20199dc9..28229c5d498 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1551,6 +1551,9 @@ aggregate_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd) if ((!shares && aggregate(tg, cpu)->rq_weight) || shares > tg->shares) shares = tg->shares; + if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) + shares = tg->shares; + aggregate(tg, cpu)->shares = shares; } @@ -1642,20 +1645,8 @@ static void __move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, int scpu, int dcpu) { - unsigned long shares; - - shares = tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares; - __update_group_shares_cpu(tg, cpu, sd, scpu); __update_group_shares_cpu(tg, cpu, sd, dcpu); - - /* - * ensure we never loose shares due to rounding errors in the - * above redistribution. - */ - shares -= tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares; - if (shares) - tg->cfs_rq[dcpu]->shares += shares; } /* @@ -1675,7 +1666,6 @@ move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, static void aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain *sd) { - unsigned long shares = aggregate(tg, cpu)->shares; int i; for_each_cpu_mask(i, sd->span) { @@ -1688,16 +1678,6 @@ aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain * } aggregate_group_shares(tg, cpu, sd); - - /* - * ensure we never loose shares due to rounding errors in the - * above redistribution. - */ - shares -= aggregate(tg, cpu)->shares; - if (shares) { - tg->cfs_rq[cpu]->shares += shares; - aggregate(tg, cpu)->shares += shares; - } } /* -- cgit v1.2.3-70-g09d2 From a25b5aca8740ea99d5e18dfc71235a52b685dcf7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:22 +0200 Subject: sched: no need to aggregate task_weight We only need to know the task_weight of the busiest rq - nothing to do if there are no tasks there. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 16 +--------------- kernel/sched_fair.c | 2 +- 2 files changed, 2 insertions(+), 16 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 28229c5d498..716cfc8e099 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -433,12 +433,6 @@ struct cfs_rq { * The sum of all runqueue weights within this span. */ unsigned long rq_weight; - - /* - * Weight contributed by tasks; this is the part we can - * influence by moving tasks around. - */ - unsigned long task_weight; } aggregate; #endif #endif @@ -1473,10 +1467,6 @@ static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); * rq_weight: * Direct sum of all the cpu's their rq weight, e.g. A would get 3 while * B would get 2. - * - * task_weight: - * Part of the rq_weight contributed by tasks; all groups except B would - * get 1, B gets 2. */ static inline struct aggregate_struct * @@ -1524,16 +1514,12 @@ static void aggregate_group_weight(struct task_group *tg, int cpu, struct sched_domain *sd) { unsigned long rq_weight = 0; - unsigned long task_weight = 0; int i; - for_each_cpu_mask(i, sd->span) { + for_each_cpu_mask(i, sd->span) rq_weight += tg->cfs_rq[i]->load.weight; - task_weight += tg->cfs_rq[i]->task_weight; - } aggregate(tg, cpu)->rq_weight = rq_weight; - aggregate(tg, cpu)->task_weight = task_weight; } /* diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index b10c0d61a2a..03b9fbd9d64 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1427,7 +1427,7 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, /* * empty group */ - if (!aggregate(tg, this_cpu)->task_weight) + if (!tg->cfs_rq[busiest_cpu]->task_weight) continue; rem_load = rem_load_move * aggregate(tg, this_cpu)->rq_weight; -- cgit v1.2.3-70-g09d2 From c8cba857b4997d5b00451d01474638f6a153f713 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:23 +0200 Subject: sched: simplify the group load balancer While thinking about the previous patch - I realized that using per domain aggregate load values in load_balance_fair() is wrong. We should use the load value for that CPU. By not needing per domain hierarchical load values we don't need to store per domain aggregate shares, which greatly simplifies all the math. It basically falls apart in two separate computations: - per domain update of the shares - per CPU update of the hierarchical load Also get rid of the move_group_shares() stuff - just re-compute the shares again after a successful load balance. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 286 ++++++++++++---------------------------------------- kernel/sched_fair.c | 15 +-- 2 files changed, 72 insertions(+), 229 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 716cfc8e099..f864b751fd1 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -406,34 +406,23 @@ struct cfs_rq { struct task_group *tg; /* group that "owns" this runqueue */ #ifdef CONFIG_SMP - unsigned long task_weight; - unsigned long shares; /* - * We need space to build a sched_domain wide view of the full task - * group tree, in order to avoid depending on dynamic memory allocation - * during the load balancing we place this in the per cpu task group - * hierarchy. This limits the load balancing to one instance per cpu, - * but more should not be needed anyway. + * the part of load.weight contributed by tasks */ - struct aggregate_struct { - /* - * load = weight(cpus) * f(tg) - * - * Where f(tg) is the recursive weight fraction assigned to - * this group. - */ - unsigned long load; + unsigned long task_weight; - /* - * part of the group weight distributed to this span. - */ - unsigned long shares; + /* + * h_load = weight * f(tg) + * + * Where f(tg) is the recursive weight fraction assigned to + * this group. + */ + unsigned long h_load; - /* - * The sum of all runqueue weights within this span. - */ - unsigned long rq_weight; - } aggregate; + /* + * this cpu's part of tg->shares + */ + unsigned long shares; #endif #endif }; @@ -1443,47 +1432,14 @@ static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); #ifdef CONFIG_FAIR_GROUP_SCHED -/* - * Group load balancing. - * - * We calculate a few balance domain wide aggregate numbers; load and weight. - * Given the pictures below, and assuming each item has equal weight: - * - * root 1 - thread - * / | \ A - group - * A 1 B - * /|\ / \ - * C 2 D 3 4 - * | | - * 5 6 - * - * load: - * A and B get 1/3-rd of the total load. C and D get 1/3-rd of A's 1/3-rd, - * which equals 1/9-th of the total load. - * - * shares: - * The weight of this group on the selected cpus. - * - * rq_weight: - * Direct sum of all the cpu's their rq weight, e.g. A would get 3 while - * B would get 2. - */ - -static inline struct aggregate_struct * -aggregate(struct task_group *tg, int cpu) -{ - return &tg->cfs_rq[cpu]->aggregate; -} - -typedef void (*aggregate_func)(struct task_group *, int, struct sched_domain *); +typedef void (*tg_visitor)(struct task_group *, int, struct sched_domain *); /* * Iterate the full tree, calling @down when first entering a node and @up when * leaving it for the final time. */ -static -void aggregate_walk_tree(aggregate_func down, aggregate_func up, - int cpu, struct sched_domain *sd) +static void +walk_tg_tree(tg_visitor down, tg_visitor up, int cpu, struct sched_domain *sd) { struct task_group *parent, *child; @@ -1507,72 +1463,6 @@ up: rcu_read_unlock(); } -/* - * Calculate the aggregate runqueue weight. - */ -static void -aggregate_group_weight(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - unsigned long rq_weight = 0; - int i; - - for_each_cpu_mask(i, sd->span) - rq_weight += tg->cfs_rq[i]->load.weight; - - aggregate(tg, cpu)->rq_weight = rq_weight; -} - -/* - * Compute the weight of this group on the given cpus. - */ -static void -aggregate_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - unsigned long shares = 0; - int i; - - for_each_cpu_mask(i, sd->span) - shares += tg->cfs_rq[i]->shares; - - if ((!shares && aggregate(tg, cpu)->rq_weight) || shares > tg->shares) - shares = tg->shares; - - if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) - shares = tg->shares; - - aggregate(tg, cpu)->shares = shares; -} - -/* - * Compute the load fraction assigned to this group, relies on the aggregate - * weight and this group's parent's load, i.e. top-down. - */ -static void -aggregate_group_load(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - unsigned long load; - - if (!tg->parent) { - int i; - - load = 0; - for_each_cpu_mask(i, sd->span) - load += cpu_rq(i)->load.weight; - - } else { - load = aggregate(tg->parent, cpu)->load; - - /* - * shares is our weight in the parent's rq so - * shares/parent->rq_weight gives our fraction of the load - */ - load *= aggregate(tg, cpu)->shares; - load /= aggregate(tg->parent, cpu)->rq_weight + 1; - } - - aggregate(tg, cpu)->load = load; -} - static void __set_se_shares(struct sched_entity *se, unsigned long shares); /* @@ -1580,16 +1470,16 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares); */ static void __update_group_shares_cpu(struct task_group *tg, int cpu, - struct sched_domain *sd, int tcpu) + unsigned long sd_shares, unsigned long sd_rq_weight) { int boost = 0; unsigned long shares; unsigned long rq_weight; - if (!tg->se[tcpu]) + if (!tg->se[cpu]) return; - rq_weight = tg->cfs_rq[tcpu]->load.weight; + rq_weight = tg->cfs_rq[cpu]->load.weight; /* * If there are currently no tasks on the cpu pretend there is one of @@ -1601,124 +1491,97 @@ __update_group_shares_cpu(struct task_group *tg, int cpu, rq_weight = NICE_0_LOAD; } + if (unlikely(rq_weight > sd_rq_weight)) + rq_weight = sd_rq_weight; + /* * \Sum shares * rq_weight * shares = ----------------------- * \Sum rq_weight * */ - shares = aggregate(tg, cpu)->shares * rq_weight; - shares /= aggregate(tg, cpu)->rq_weight + 1; + shares = (sd_shares * rq_weight) / (sd_rq_weight + 1); /* * record the actual number of shares, not the boosted amount. */ - tg->cfs_rq[tcpu]->shares = boost ? 0 : shares; + tg->cfs_rq[cpu]->shares = boost ? 0 : shares; if (shares < MIN_SHARES) shares = MIN_SHARES; else if (shares > MAX_SHARES) shares = MAX_SHARES; - __set_se_shares(tg->se[tcpu], shares); + __set_se_shares(tg->se[cpu], shares); } /* - * Re-adjust the weights on the cpu the task came from and on the cpu the - * task went to. + * Re-compute the task group their per cpu shares over the given domain. + * This needs to be done in a bottom-up fashion because the rq weight of a + * parent group depends on the shares of its child groups. */ static void -__move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, - int scpu, int dcpu) +tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd) { - __update_group_shares_cpu(tg, cpu, sd, scpu); - __update_group_shares_cpu(tg, cpu, sd, dcpu); -} + unsigned long rq_weight = 0; + unsigned long shares = 0; + int i; -/* - * Because changing a group's shares changes the weight of the super-group - * we need to walk up the tree and change all shares until we hit the root. - */ -static void -move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd, - int scpu, int dcpu) -{ - while (tg) { - __move_group_shares(tg, cpu, sd, scpu, dcpu); - tg = tg->parent; + for_each_cpu_mask(i, sd->span) { + rq_weight += tg->cfs_rq[i]->load.weight; + shares += tg->cfs_rq[i]->shares; } -} -static void -aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - int i; + if ((!shares && rq_weight) || shares > tg->shares) + shares = tg->shares; + + if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) + shares = tg->shares; for_each_cpu_mask(i, sd->span) { struct rq *rq = cpu_rq(i); unsigned long flags; spin_lock_irqsave(&rq->lock, flags); - __update_group_shares_cpu(tg, cpu, sd, i); + __update_group_shares_cpu(tg, i, shares, rq_weight); spin_unlock_irqrestore(&rq->lock, flags); } - - aggregate_group_shares(tg, cpu, sd); } /* - * Calculate the accumulative weight and recursive load of each task group - * while walking down the tree. + * Compute the cpu's hierarchical load factor for each task group. + * This needs to be done in a top-down fashion because the load of a child + * group is a fraction of its parents load. */ static void -aggregate_get_down(struct task_group *tg, int cpu, struct sched_domain *sd) +tg_load_down(struct task_group *tg, int cpu, struct sched_domain *sd) { - aggregate_group_weight(tg, cpu, sd); - aggregate_group_shares(tg, cpu, sd); - aggregate_group_load(tg, cpu, sd); -} - -/* - * Rebalance the cpu shares while walking back up the tree. - */ -static void -aggregate_get_up(struct task_group *tg, int cpu, struct sched_domain *sd) -{ - aggregate_group_set_shares(tg, cpu, sd); -} - -static void -aggregate_get_nop(struct task_group *tg, int cpu, struct sched_domain *sd) -{ -} - -static DEFINE_PER_CPU(spinlock_t, aggregate_lock); + unsigned long load; -static void __init init_aggregate(void) -{ - int i; + if (!tg->parent) { + load = cpu_rq(cpu)->load.weight; + } else { + load = tg->parent->cfs_rq[cpu]->h_load; + load *= tg->cfs_rq[cpu]->shares; + load /= tg->parent->cfs_rq[cpu]->load.weight + 1; + } - for_each_possible_cpu(i) - spin_lock_init(&per_cpu(aggregate_lock, i)); + tg->cfs_rq[cpu]->h_load = load; } -static int get_aggregate(int cpu, struct sched_domain *sd) +static void +tg_nop(struct task_group *tg, int cpu, struct sched_domain *sd) { - if (!spin_trylock(&per_cpu(aggregate_lock, cpu))) - return 0; - - aggregate_walk_tree(aggregate_get_down, aggregate_get_up, cpu, sd); - return 1; } -static void update_aggregate(int cpu, struct sched_domain *sd) +static void update_shares(struct sched_domain *sd) { - aggregate_walk_tree(aggregate_get_down, aggregate_get_nop, cpu, sd); + walk_tg_tree(tg_nop, tg_shares_up, 0, sd); } -static void put_aggregate(int cpu, struct sched_domain *sd) +static void update_h_load(int cpu) { - spin_unlock(&per_cpu(aggregate_lock, cpu)); + walk_tg_tree(tg_load_down, tg_nop, cpu, NULL); } static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) @@ -1728,22 +1591,10 @@ static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) #else -static inline void init_aggregate(void) -{ -} - -static inline int get_aggregate(int cpu, struct sched_domain *sd) -{ - return 0; -} - -static inline void update_aggregate(int cpu, struct sched_domain *sd) +static inline void update_shares(struct sched_domain *sd) { } -static inline void put_aggregate(int cpu, struct sched_domain *sd) -{ -} #endif #endif @@ -2172,12 +2023,6 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) int load_idx = sd->forkexec_idx; int imbalance = 100 + (sd->imbalance_pct-100)/2; - /* - * now that we have both rqs locked the rq weight won't change - * anymore - so update the stats. - */ - update_aggregate(this_cpu, sd); - do { unsigned long load, avg_load; int local_group; @@ -3521,12 +3366,9 @@ static int load_balance(int this_cpu, struct rq *this_rq, unsigned long imbalance; struct rq *busiest; unsigned long flags; - int unlock_aggregate; cpus_setall(*cpus); - unlock_aggregate = get_aggregate(this_cpu, sd); - /* * When power savings policy is enabled for the parent domain, idle * sibling can pick up load irrespective of busy siblings. In this case, @@ -3540,6 +3382,7 @@ static int load_balance(int this_cpu, struct rq *this_rq, schedstat_inc(sd, lb_count[idle]); redo: + update_shares(sd); group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, cpus, balance); @@ -3663,8 +3506,8 @@ out_one_pinned: else ld_moved = 0; out: - if (unlock_aggregate) - put_aggregate(this_cpu, sd); + if (ld_moved) + update_shares(sd); return ld_moved; } @@ -8019,7 +7862,6 @@ void __init sched_init(void) } #ifdef CONFIG_SMP - init_aggregate(); init_defrootdomain(); #endif diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 03b9fbd9d64..7b8d664d6f2 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1421,17 +1421,20 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, struct task_group *tg; rcu_read_lock(); + update_h_load(busiest_cpu); + list_for_each_entry(tg, &task_groups, list) { + struct cfs_rq *busiest_cfs_rq = tg->cfs_rq[busiest_cpu]; long rem_load, moved_load; /* * empty group */ - if (!tg->cfs_rq[busiest_cpu]->task_weight) + if (!busiest_cfs_rq->task_weight) continue; - rem_load = rem_load_move * aggregate(tg, this_cpu)->rq_weight; - rem_load /= aggregate(tg, this_cpu)->load + 1; + rem_load = rem_load_move * busiest_cfs_rq->load.weight; + rem_load /= busiest_cfs_rq->h_load + 1; moved_load = __load_balance_fair(this_rq, this_cpu, busiest, rem_load, sd, idle, all_pinned, this_best_prio, @@ -1440,10 +1443,8 @@ load_balance_fair(struct rq *this_rq, int this_cpu, struct rq *busiest, if (!moved_load) continue; - move_group_shares(tg, this_cpu, sd, busiest_cpu, this_cpu); - - moved_load *= aggregate(tg, this_cpu)->load; - moved_load /= aggregate(tg, this_cpu)->rq_weight + 1; + moved_load *= busiest_cfs_rq->h_load; + moved_load /= busiest_cfs_rq->load.weight + 1; rem_load_move -= moved_load; if (rem_load_move < 0) -- cgit v1.2.3-70-g09d2 From 3e5459b4bea3ca2618cc02d56d12639f2cba531d Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:24 +0200 Subject: sched: fix newidle smp group balancing Re-compute the shares on newidle - so we can make a decision based on recent data. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index f864b751fd1..cdd09462fc9 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1579,6 +1579,13 @@ static void update_shares(struct sched_domain *sd) walk_tg_tree(tg_nop, tg_shares_up, 0, sd); } +static void update_shares_locked(struct rq *rq, struct sched_domain *sd) +{ + spin_unlock(&rq->lock); + update_shares(sd); + spin_lock(&rq->lock); +} + static void update_h_load(int cpu) { walk_tg_tree(tg_load_down, tg_nop, cpu, NULL); @@ -1595,6 +1602,10 @@ static inline void update_shares(struct sched_domain *sd) { } +static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd) +{ +} + #endif #endif @@ -3543,6 +3554,7 @@ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd, schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); redo: + update_shares_locked(this_rq, sd); group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, &sd_idle, cpus, NULL); if (!group) { @@ -3586,6 +3598,7 @@ redo: } else sd->nr_balance_failed = 0; + update_shares_locked(this_rq, sd); return ld_moved; out_balanced: -- cgit v1.2.3-70-g09d2 From 039a1c41b3a489e34593ea1e1687f6fdad6b13ab Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:25 +0200 Subject: sched: fix sched_balance_self() smp group balancing Finding the least idle cpu is more accurate when done with updated shares. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index cdd09462fc9..39d5495540d 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2128,6 +2128,9 @@ static int sched_balance_self(int cpu, int flag) sd = tmp; } + if (sd) + update_shares(sd); + while (sd) { cpumask_t span, tmpmask; struct sched_group *group; -- cgit v1.2.3-70-g09d2 From a8a51d5e59561aa5b4d66e19eca819b537783e8f Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:26 +0200 Subject: sched: persistent average load per task Remove the fall-back to SCHED_LOAD_SCALE by remembering the previous value of cpu_avg_load_per_task() - this is useful because of the hierarchical group model in which task weight can be much smaller. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 39d5495540d..6a6b0139eb3 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -554,6 +554,8 @@ struct rq { int cpu; int online; + unsigned long avg_load_per_task; + struct task_struct *migration_thread; struct list_head migration_queue; #endif @@ -1427,9 +1429,18 @@ static inline void dec_cpu_load(struct rq *rq, unsigned long load) #ifdef CONFIG_SMP static unsigned long source_load(int cpu, int type); static unsigned long target_load(int cpu, int type); -static unsigned long cpu_avg_load_per_task(int cpu); static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); +static unsigned long cpu_avg_load_per_task(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + + if (rq->nr_running) + rq->avg_load_per_task = rq->load.weight / rq->nr_running; + + return rq->avg_load_per_task; +} + #ifdef CONFIG_FAIR_GROUP_SCHED typedef void (*tg_visitor)(struct task_group *, int, struct sched_domain *); @@ -2010,18 +2021,6 @@ static unsigned long target_load(int cpu, int type) return max(rq->cpu_load[type-1], total); } -/* - * Return the average load per task on the cpu's run queue - */ -static unsigned long cpu_avg_load_per_task(int cpu) -{ - struct rq *rq = cpu_rq(cpu); - unsigned long total = weighted_cpuload(cpu); - unsigned long n = rq->nr_running; - - return n ? total / n : SCHED_LOAD_SCALE; -} - /* * find_idlest_group finds and returns the least busy CPU group within the * domain. -- cgit v1.2.3-70-g09d2 From 408ed066b11cf9ee4536573b4269ee3613bd735e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:28 +0200 Subject: sched: hierarchical load vs find_busiest_group find_busiest_group() has some assumptions about task weight being in the NICE_0_LOAD range. Hierarchical task groups break this assumption - fix this by replacing it with the average task weight, which will adapt the situation. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 6a6b0139eb3..5e2aa394a81 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3050,6 +3050,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, max_load = this_load = total_load = total_pwr = 0; busiest_load_per_task = busiest_nr_running = 0; this_load_per_task = this_nr_running = 0; + if (idle == CPU_NOT_IDLE) load_idx = sd->busy_idx; else if (idle == CPU_NEWLY_IDLE) @@ -3064,6 +3065,8 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, int __group_imb = 0; unsigned int balance_cpu = -1, first_idle_cpu = 0; unsigned long sum_nr_running, sum_weighted_load; + unsigned long sum_avg_load_per_task; + unsigned long avg_load_per_task; local_group = cpu_isset(this_cpu, group->cpumask); @@ -3072,6 +3075,8 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, /* Tally up the load of all CPUs in the group */ sum_weighted_load = sum_nr_running = avg_load = 0; + sum_avg_load_per_task = avg_load_per_task = 0; + max_cpu_load = 0; min_cpu_load = ~0UL; @@ -3105,6 +3110,8 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, avg_load += load; sum_nr_running += rq->nr_running; sum_weighted_load += weighted_cpuload(i); + + sum_avg_load_per_task += cpu_avg_load_per_task(i); } /* @@ -3126,7 +3133,20 @@ find_busiest_group(struct sched_domain *sd, int this_cpu, avg_load = sg_div_cpu_power(group, avg_load * SCHED_LOAD_SCALE); - if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE) + + /* + * Consider the group unbalanced when the imbalance is larger + * than the average weight of two tasks. + * + * APZ: with cgroup the avg task weight can vary wildly and + * might not be a suitable number - should we keep a + * normalized nr_running number somewhere that negates + * the hierarchy? + */ + avg_load_per_task = sg_div_cpu_power(group, + sum_avg_load_per_task * SCHED_LOAD_SCALE); + + if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) __group_imb = 1; group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; @@ -3267,9 +3287,9 @@ small_imbalance: if (busiest_load_per_task > this_load_per_task) imbn = 1; } else - this_load_per_task = SCHED_LOAD_SCALE; + this_load_per_task = cpu_avg_load_per_task(this_cpu); - if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= + if (max_load - this_load + 2*busiest_load_per_task >= busiest_load_per_task * imbn) { *imbalance = busiest_load_per_task; return busiest; -- cgit v1.2.3-70-g09d2 From 051c67640e771fd6ad1b676fc0c16c379b3c6f80 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:31 +0200 Subject: sched: remove prio preference from balance decisions Priority looses much of its meaning in a hierarchical context. So don't use it in balance decisions. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 5e2aa394a81..10d43f5bf0f 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2896,7 +2896,7 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, enum cpu_idle_type idle, int *all_pinned, int *this_best_prio, struct rq_iterator *iterator) { - int loops = 0, pulled = 0, pinned = 0, skip_for_load; + int loops = 0, pulled = 0, pinned = 0; struct task_struct *p; long rem_load_move = max_load_move; @@ -2912,14 +2912,8 @@ balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, next: if (!p || loops++ > sysctl_sched_nr_migrate) goto out; - /* - * To help distribute high priority tasks across CPUs we don't - * skip a task if it will be the highest priority task (i.e. smallest - * prio value) on its new queue regardless of its load weight - */ - skip_for_load = (p->se.load.weight >> 1) > rem_load_move + - SCHED_LOAD_SCALE_FUZZ; - if ((skip_for_load && p->prio >= *this_best_prio) || + + if ((p->se.load.weight >> 1) > rem_load_move || !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { p = iterator->next(iterator->arg); goto next; -- cgit v1.2.3-70-g09d2 From 93b75217df39e6d75889cc6f8050343286aff4a5 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:33 +0200 Subject: sched: disable source/target_load bias The bias given by source/target_load functions can be very large, disable it by default to get faster convergence. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 4 ++-- kernel/sched_features.h | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 10d43f5bf0f..6c5eb3bc37e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2000,7 +2000,7 @@ static unsigned long source_load(int cpu, int type) struct rq *rq = cpu_rq(cpu); unsigned long total = weighted_cpuload(cpu); - if (type == 0) + if (type == 0 || !sched_feat(LB_BIAS)) return total; return min(rq->cpu_load[type-1], total); @@ -2015,7 +2015,7 @@ static unsigned long target_load(int cpu, int type) struct rq *rq = cpu_rq(cpu); unsigned long total = weighted_cpuload(cpu); - if (type == 0) + if (type == 0 || !sched_feat(LB_BIAS)) return total; return max(rq->cpu_load[type-1], total); diff --git a/kernel/sched_features.h b/kernel/sched_features.h index 04123af2e67..d56e3053e74 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -8,3 +8,4 @@ SCHED_FEAT(SYNC_WAKEUPS, 1) SCHED_FEAT(HRTICK, 1) SCHED_FEAT(DOUBLE_TICK, 0) SCHED_FEAT(ASYM_GRAN, 1) +SCHED_FEAT(LB_BIAS, 0) \ No newline at end of file -- cgit v1.2.3-70-g09d2 From cd80917e4ff465ea77106f8e4fb631eedc4cf426 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:34 +0200 Subject: sched: fix shares boost logic In case the domain is empty, pretend there is a single task on each cpu, so that together with the boost logic we end up giving 1/n shares to each cpu. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 6c5eb3bc37e..1cff969f664 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1549,6 +1549,9 @@ tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd) if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) shares = tg->shares; + if (!rq_weight) + rq_weight = cpus_weight(sd->span) * NICE_0_LOAD; + for_each_cpu_mask(i, sd->span) { struct rq *rq = cpu_rq(i); unsigned long flags; -- cgit v1.2.3-70-g09d2 From 2398f2c6d34b43025f274fc42eaca34d23ec2320 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:35 +0200 Subject: sched: update shares on wakeup We found that the affine wakeup code needs rather accurate load figures to be effective. The trouble is that updating the load figures is fairly expensive with group scheduling. Therefore ratelimit the updating. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- include/linux/sched.h | 3 +++ kernel/sched.c | 30 +++++++++++++++++++++++++++++- kernel/sched_features.h | 3 ++- kernel/sysctl.c | 8 ++++++++ 4 files changed, 42 insertions(+), 2 deletions(-) (limited to 'kernel/sched.c') diff --git a/include/linux/sched.h b/include/linux/sched.h index eaf821072db..835b6c6fcc5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -783,6 +783,8 @@ struct sched_domain { unsigned int balance_interval; /* initialise to 1. units in ms. */ unsigned int nr_balance_failed; /* initialise to 0 */ + u64 last_update; + #ifdef CONFIG_SCHEDSTATS /* load_balance() stats */ unsigned int lb_count[CPU_MAX_IDLE_TYPES]; @@ -1605,6 +1607,7 @@ extern unsigned int sysctl_sched_child_runs_first; extern unsigned int sysctl_sched_features; extern unsigned int sysctl_sched_migration_cost; extern unsigned int sysctl_sched_nr_migrate; +extern unsigned int sysctl_sched_shares_ratelimit; int sched_nr_latency_handler(struct ctl_table *table, int write, struct file *file, void __user *buffer, size_t *length, diff --git a/kernel/sched.c b/kernel/sched.c index 1cff969f664..62db0891025 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -777,6 +777,12 @@ late_initcall(sched_init_debug); */ const_debug unsigned int sysctl_sched_nr_migrate = 32; +/* + * ratelimit for updating the group shares. + * default: 0.5ms + */ +const_debug unsigned int sysctl_sched_shares_ratelimit = 500000; + /* * period over which we measure -rt task cpu usage in us. * default: 1s @@ -1590,7 +1596,13 @@ tg_nop(struct task_group *tg, int cpu, struct sched_domain *sd) static void update_shares(struct sched_domain *sd) { - walk_tg_tree(tg_nop, tg_shares_up, 0, sd); + u64 now = cpu_clock(raw_smp_processor_id()); + s64 elapsed = now - sd->last_update; + + if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) { + sd->last_update = now; + walk_tg_tree(tg_nop, tg_shares_up, 0, sd); + } } static void update_shares_locked(struct rq *rq, struct sched_domain *sd) @@ -2199,6 +2211,22 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) if (!sched_feat(SYNC_WAKEUPS)) sync = 0; +#ifdef CONFIG_SMP + if (sched_feat(LB_WAKEUP_UPDATE)) { + struct sched_domain *sd; + + this_cpu = raw_smp_processor_id(); + cpu = task_cpu(p); + + for_each_domain(this_cpu, sd) { + if (cpu_isset(cpu, sd->span)) { + update_shares(sd); + break; + } + } + } +#endif + smp_wmb(); rq = task_rq_lock(p, &flags); old_state = p->state; diff --git a/kernel/sched_features.h b/kernel/sched_features.h index d56e3053e74..7d616d2a2a3 100644 --- a/kernel/sched_features.h +++ b/kernel/sched_features.h @@ -8,4 +8,5 @@ SCHED_FEAT(SYNC_WAKEUPS, 1) SCHED_FEAT(HRTICK, 1) SCHED_FEAT(DOUBLE_TICK, 0) SCHED_FEAT(ASYM_GRAN, 1) -SCHED_FEAT(LB_BIAS, 0) \ No newline at end of file +SCHED_FEAT(LB_BIAS, 0) +SCHED_FEAT(LB_WAKEUP_UPDATE, 1) diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 29116652dca..fe8cdc80ff0 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -264,6 +264,14 @@ static struct ctl_table kern_table[] = { .extra1 = &min_wakeup_granularity_ns, .extra2 = &max_wakeup_granularity_ns, }, + { + .ctl_name = CTL_UNNUMBERED, + .procname = "sched_shares_ratelimit", + .data = &sysctl_sched_shares_ratelimit, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, { .ctl_name = CTL_UNNUMBERED, .procname = "sched_child_runs_first", -- cgit v1.2.3-70-g09d2 From 83378269a5fad98f562ebc0f09c349575e6cbfe1 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:37 +0200 Subject: sched: correct wakeup weight calculations rw_i = {2, 4, 1, 0} s_i = {2/7, 4/7, 1/7, 0} wakeup on cpu0, weight=1 rw'_i = {3, 4, 1, 0} s'_i = {3/8, 4/8, 1/8, 0} s_0 = S * rw_0 / \Sum rw_j -> \Sum rw_j = S*rw_0/s_0 = 1*2*7/2 = 7 (correct) s'_0 = S * (rw_0 + 1) / (\Sum rw_j + 1) = 1 * (2+1) / (7+1) = 3/8 (correct so we find that adding 1 to cpu0 gains 5/56 in weight if say the other cpu were, cpu1, we'd also have to calculate its 4/56 loss Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 4 ++++ kernel/sched_fair.c | 48 ++++++++++++++++++++++++++---------------------- 2 files changed, 30 insertions(+), 22 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 62db0891025..01d3e51b711 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -365,6 +365,10 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu) #else static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } +static inline struct task_group *task_group(struct task_struct *p) +{ + return NULL; +} #endif /* CONFIG_GROUP_SCHED */ diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 26ebe180cde..bed2f71e63d 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1074,10 +1074,10 @@ static inline int wake_idle(int cpu, struct task_struct *p) static const struct sched_class fair_sched_class; #ifdef CONFIG_FAIR_GROUP_SCHED -static unsigned long effective_load(struct task_group *tg, long wl, int cpu) +static unsigned long effective_load(struct task_group *tg, int cpu, + unsigned long wl, unsigned long wg) { struct sched_entity *se = tg->se[cpu]; - long wg = wl; for_each_sched_entity(se) { #define D(n) (likely(n) ? (n) : 1) @@ -1092,6 +1092,13 @@ static unsigned long effective_load(struct task_group *tg, long wl, int cpu) b = S*rw + s*wg; wl = s*(a-b)/D(b); + /* + * Assume the group is already running and will + * thus already be accounted for in the weight. + * + * That is, moving shares between CPUs, does not + * alter the group weight. + */ wg = 0; #undef D } @@ -1099,26 +1106,12 @@ static unsigned long effective_load(struct task_group *tg, long wl, int cpu) return wl; } -static unsigned long task_load_sub(struct task_struct *p) -{ - return effective_load(task_group(p), -(long)p->se.load.weight, task_cpu(p)); -} - -static unsigned long task_load_add(struct task_struct *p, int cpu) -{ - return effective_load(task_group(p), p->se.load.weight, cpu); -} - #else -static unsigned long task_load_sub(struct task_struct *p) +static inline unsigned long effective_load(struct task_group *tg, int cpu, + unsigned long wl, unsigned long wg) { - return -p->se.load.weight; -} - -static unsigned long task_load_add(struct task_struct *p, int cpu) -{ - return p->se.load.weight; + return wl; } #endif @@ -1130,8 +1123,10 @@ wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq, unsigned int imbalance) { struct task_struct *curr = this_rq->curr; + struct task_group *tg; unsigned long tl = this_load; unsigned long tl_per_task; + unsigned long weight; int balanced; if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS)) @@ -1142,10 +1137,19 @@ wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq, * effect of the currently running task from the load * of the current CPU: */ - if (sync) - tl += task_load_sub(current); + if (sync) { + tg = task_group(current); + weight = current->se.load.weight; + + tl += effective_load(tg, this_cpu, -weight, -weight); + load += effective_load(tg, prev_cpu, 0, -weight); + } + + tg = task_group(p); + weight = p->se.load.weight; - balanced = 100*(tl + task_load_add(p, this_cpu)) <= imbalance*load; + balanced = 100*(tl + effective_load(tg, this_cpu, weight, weight)) <= + imbalance*(load + effective_load(tg, prev_cpu, 0, weight)); /* * If the currently running task will sleep within -- cgit v1.2.3-70-g09d2 From f1d239f73200a5803a89e5929fb3abc1596b7589 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:38 +0200 Subject: sched: incremental effective_load() Increase the accuracy of the effective_load values. Not only consider the current increment (as per the attempted wakeup), but also consider the delta between when we last adjusted the shares and the current situation. Signed-off-by: Peter Zijlstra Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 6 ++++++ kernel/sched_fair.c | 18 +++++++++++++++--- 2 files changed, 21 insertions(+), 3 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 01d3e51b711..7613f69f097 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -427,6 +427,11 @@ struct cfs_rq { * this cpu's part of tg->shares */ unsigned long shares; + + /* + * load.weight at the time we set shares + */ + unsigned long rq_weight; #endif #endif }; @@ -1527,6 +1532,7 @@ __update_group_shares_cpu(struct task_group *tg, int cpu, * record the actual number of shares, not the boosted amount. */ tg->cfs_rq[cpu]->shares = boost ? 0 : shares; + tg->cfs_rq[cpu]->rq_weight = rq_weight; if (shares < MIN_SHARES) shares = MIN_SHARES; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index bed2f71e63d..e87f1a52f62 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1074,10 +1074,22 @@ static inline int wake_idle(int cpu, struct task_struct *p) static const struct sched_class fair_sched_class; #ifdef CONFIG_FAIR_GROUP_SCHED -static unsigned long effective_load(struct task_group *tg, int cpu, - unsigned long wl, unsigned long wg) +static long effective_load(struct task_group *tg, int cpu, + long wl, long wg) { struct sched_entity *se = tg->se[cpu]; + long more_w; + + if (!tg->parent) + return wl; + + /* + * Instead of using this increment, also add the difference + * between when the shares were last updated and now. + */ + more_w = se->my_q->load.weight - se->my_q->rq_weight; + wl += more_w; + wg += more_w; for_each_sched_entity(se) { #define D(n) (likely(n) ? (n) : 1) @@ -1086,7 +1098,7 @@ static unsigned long effective_load(struct task_group *tg, int cpu, S = se->my_q->tg->shares; s = se->my_q->shares; - rw = se->my_q->load.weight; + rw = se->my_q->rq_weight; a = S*(rw + wl); b = S*rw + s*wg; -- cgit v1.2.3-70-g09d2 From 34e83e850f5e5ee2a18cd77a5d70d31972a632e6 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 27 Jun 2008 15:42:36 +0200 Subject: sched: build fix MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit fix: kernel/sched.c: In function ‘sched_group_set_shares': kernel/sched.c:8635: error: implicit declaration of function ‘cfs_rq_set_shares' Signed-off-by: Ingo Molnar --- kernel/sched.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 7613f69f097..058250a63b6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1627,11 +1627,6 @@ static void update_h_load(int cpu) walk_tg_tree(tg_load_down, tg_nop, cpu, NULL); } -static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) -{ - cfs_rq->shares = shares; -} - #else static inline void update_shares(struct sched_domain *sd) @@ -1646,6 +1641,13 @@ static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd) #endif +static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) +{ +#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED) + cfs_rq->shares = shares; +#endif +} + #include "sched_stats.h" #include "sched_idletask.c" #include "sched_fair.c" -- cgit v1.2.3-70-g09d2 From 30432094a7f506ad24997a3ba6aed913ab61c01d Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Fri, 27 Jun 2008 21:35:50 +0200 Subject: sched: fix warning This patch fixes the following warning: kernel/sched.c:1667: warning: 'cfs_rq_set_shares' defined but not used This seems the correct way to fix this; cfs_rq_set_shares() is only used in a single place, which is also inside #ifdef CONFIG_FAIR_GROUP_SCHED. Signed-off-by: Vegard Nossum Cc: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 058250a63b6..677c80b9a6b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1641,12 +1641,14 @@ static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd) #endif +#ifdef CONFIG_FAIR_GROUP_SCHED static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) { -#if defined(CONFIG_SMP) && defined(CONFIG_FAIR_GROUP_SCHED) +#ifdef CONFIG_SMP cfs_rq->shares = shares; #endif } +#endif #include "sched_stats.h" #include "sched_idletask.c" -- cgit v1.2.3-70-g09d2 From c4acb2c0669c5c5c9b28e9d02a34b5c67edf7092 Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Fri, 27 Jun 2008 14:29:55 -0600 Subject: sched: terminate newidle balancing once at least one task has moved over Inspired by Peter Zijlstra. Signed-off-by: Gregory Haskins Cc: npiggin@suse.de Cc: rostedt@goodmis.org Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index 677c80b9a6b..d99aeabeb72 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3013,6 +3013,10 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, max_load_move - total_load_moved, sd, idle, all_pinned, &this_best_prio); class = class->next; + + if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) + break; + } while (class && max_load_move > total_load_moved); return total_load_moved > 0; -- cgit v1.2.3-70-g09d2 From 2087a1ad822cd3a68b73338457047fcc54da726b Mon Sep 17 00:00:00 2001 From: Gregory Haskins Date: Fri, 27 Jun 2008 14:30:00 -0600 Subject: sched: add avg-overlap support to RT tasks We have the notion of tracking process-coupling (a.k.a. buddy-wake) via the p->se.last_wake / p->se.avg_overlap facilities, but it is only used for cfs to cfs interactions. There is no reason why an rt to cfs interaction cannot share in establishing a relationhip in a similar manner. Because PREEMPT_RT runs many kernel threads as FIFO priority, we often times have heavy interaction between RT threads waking CFS applications. This patch offers a substantial boost (50-60%+) in perfomance under those circumstances. Signed-off-by: Gregory Haskins Cc: npiggin@suse.de Cc: rostedt@goodmis.org Acked-by: Peter Zijlstra Signed-off-by: Ingo Molnar --- kernel/sched.c | 14 ++++++++++++++ kernel/sched_fair.c | 21 ++------------------- 2 files changed, 16 insertions(+), 19 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index d99aeabeb72..bbc40c3a065 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1693,6 +1693,12 @@ static void set_load_weight(struct task_struct *p) p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; } +static void update_avg(u64 *avg, u64 sample) +{ + s64 diff = sample - *avg; + *avg += diff >> 3; +} + static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) { sched_info_queued(p); @@ -1702,6 +1708,12 @@ static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) { + if (sleep && p->se.last_wakeup) { + update_avg(&p->se.avg_overlap, + p->se.sum_exec_runtime - p->se.last_wakeup); + p->se.last_wakeup = 0; + } + p->sched_class->dequeue_task(rq, p, sleep); p->se.on_rq = 0; } @@ -2313,6 +2325,8 @@ out_running: p->sched_class->task_wake_up(rq, p); #endif out: + current->se.last_wakeup = current->se.sum_exec_runtime; + task_rq_unlock(rq, &flags); return success; diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 2e43d4a748c..f2aa987027d 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -726,21 +726,6 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup) __enqueue_entity(cfs_rq, se); } -static void update_avg(u64 *avg, u64 sample) -{ - s64 diff = sample - *avg; - *avg += diff >> 3; -} - -static void update_avg_stats(struct cfs_rq *cfs_rq, struct sched_entity *se) -{ - if (!se->last_wakeup) - return; - - update_avg(&se->avg_overlap, se->sum_exec_runtime - se->last_wakeup); - se->last_wakeup = 0; -} - static void dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) { @@ -751,7 +736,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep) update_stats_dequeue(cfs_rq, se); if (sleep) { - update_avg_stats(cfs_rq, se); #ifdef CONFIG_SCHEDSTATS if (entity_is_task(se)) { struct task_struct *tsk = task_of(se); @@ -1196,9 +1180,9 @@ wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq, * a reasonable amount of time then attract this newly * woken task: */ - if (sync && balanced && curr->sched_class == &fair_sched_class) { + if (sync && balanced) { if (curr->se.avg_overlap < sysctl_sched_migration_cost && - p->se.avg_overlap < sysctl_sched_migration_cost) + p->se.avg_overlap < sysctl_sched_migration_cost) return 1; } @@ -1359,7 +1343,6 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p) return; } - se->last_wakeup = se->sum_exec_runtime; if (unlikely(se == pse)) return; -- cgit v1.2.3-70-g09d2 From 46ac22bab42cc868b9c1d0e915ddbc8e8065a44d Mon Sep 17 00:00:00 2001 From: Ankita Garg Date: Tue, 1 Jul 2008 14:30:06 +0530 Subject: sched: fix accounting in task delay accounting & migration On Thu, Jun 19, 2008 at 12:27:14PM +0200, Peter Zijlstra wrote: > On Thu, 2008-06-05 at 10:50 +0530, Ankita Garg wrote: > > > Thanks Peter for the explanation... > > > > I agree with the above and that is the reason why I did not see weird > > values with cpu_time. But, run_delay still would suffer skews as the end > > points for delta could be taken on different cpus due to migration (more > > so on RT kernel due to the push-pull operations). With the below patch, > > I could not reproduce the issue I had seen earlier. After every dequeue, > > we take the delta and start wait measurements from zero when moved to a > > different rq. > > OK, so task delay delay accounting is broken because it doesn't take > migration into account. > > What you've done is make it symmetric wrt enqueue, and account it like > > cpu0 cpu1 > > enqueue > > dequeue > enqueue > > run > > Where you add both d1 and d2 to the run_delay,.. right? > Thanks for reviewing the patch. The above is exactly what I have done. > This seems like a good fix, however it looks like the patch will break > compilation in !CONFIG_SCHEDSTATS && !CONFIG_TASK_DELAY_ACCT, of it > failing to provide a stub for sched_info_dequeue() in that case. Fixed. Pl. find the new patch below. Signed-off-by: Ankita Garg Acked-by: Peter Zijlstra Cc: Gregory Haskins Cc: rostedt@goodmis.org Cc: suresh.b.siddha@intel.com Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dhaval@linux.vnet.ibm.com Cc: vatsa@linux.vnet.ibm.com Cc: David Bahi Signed-off-by: Ingo Molnar --- kernel/sched.c | 1 + kernel/sched_stats.h | 42 +++++++++++++++++++++++++++++++++--------- 2 files changed, 34 insertions(+), 9 deletions(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index bbc40c3a065..996bc15196a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1714,6 +1714,7 @@ static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) p->se.last_wakeup = 0; } + sched_info_dequeued(p); p->sched_class->dequeue_task(rq, p, sleep); p->se.on_rq = 0; } diff --git a/kernel/sched_stats.h b/kernel/sched_stats.h index 80179ef7450..8385d43987e 100644 --- a/kernel/sched_stats.h +++ b/kernel/sched_stats.h @@ -118,6 +118,13 @@ rq_sched_info_depart(struct rq *rq, unsigned long long delta) if (rq) rq->rq_sched_info.cpu_time += delta; } + +static inline void +rq_sched_info_dequeued(struct rq *rq, unsigned long long delta) +{ + if (rq) + rq->rq_sched_info.run_delay += delta; +} # define schedstat_inc(rq, field) do { (rq)->field++; } while (0) # define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0) # define schedstat_set(var, val) do { var = (val); } while (0) @@ -126,6 +133,9 @@ static inline void rq_sched_info_arrive(struct rq *rq, unsigned long long delta) {} static inline void +rq_sched_info_dequeued(struct rq *rq, unsigned long long delta) +{} +static inline void rq_sched_info_depart(struct rq *rq, unsigned long long delta) {} # define schedstat_inc(rq, field) do { } while (0) @@ -134,6 +144,11 @@ rq_sched_info_depart(struct rq *rq, unsigned long long delta) #endif #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) +static inline void sched_info_reset_dequeued(struct task_struct *t) +{ + t->sched_info.last_queued = 0; +} + /* * Called when a process is dequeued from the active array and given * the cpu. We should note that with the exception of interactive @@ -143,15 +158,22 @@ rq_sched_info_depart(struct rq *rq, unsigned long long delta) * active queue, thus delaying tasks in the expired queue from running; * see scheduler_tick()). * - * This function is only called from sched_info_arrive(), rather than - * dequeue_task(). Even though a task may be queued and dequeued multiple - * times as it is shuffled about, we're really interested in knowing how - * long it was from the *first* time it was queued to the time that it - * finally hit a cpu. + * Though we are interested in knowing how long it was from the *first* time a + * task was queued to the time that it finally hit a cpu, we call this routine + * from dequeue_task() to account for possible rq->clock skew across cpus. The + * delta taken on each cpu would annul the skew. */ static inline void sched_info_dequeued(struct task_struct *t) { - t->sched_info.last_queued = 0; + unsigned long long now = task_rq(t)->clock, delta = 0; + + if (unlikely(sched_info_on())) + if (t->sched_info.last_queued) + delta = now - t->sched_info.last_queued; + sched_info_reset_dequeued(t); + t->sched_info.run_delay += delta; + + rq_sched_info_dequeued(task_rq(t), delta); } /* @@ -165,7 +187,7 @@ static void sched_info_arrive(struct task_struct *t) if (t->sched_info.last_queued) delta = now - t->sched_info.last_queued; - sched_info_dequeued(t); + sched_info_reset_dequeued(t); t->sched_info.run_delay += delta; t->sched_info.last_arrival = now; t->sched_info.pcount++; @@ -242,7 +264,9 @@ sched_info_switch(struct task_struct *prev, struct task_struct *next) __sched_info_switch(prev, next); } #else -#define sched_info_queued(t) do { } while (0) -#define sched_info_switch(t, next) do { } while (0) +#define sched_info_queued(t) do { } while (0) +#define sched_info_reset_dequeued(t) do { } while (0) +#define sched_info_dequeued(t) do { } while (0) +#define sched_info_switch(t, next) do { } while (0) #endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */ -- cgit v1.2.3-70-g09d2