summaryrefslogtreecommitdiffstats
path: root/kernel/sched.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c333
1 files changed, 280 insertions, 53 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 41541d79e3c..d42992bccdf 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -426,9 +426,7 @@ struct root_domain {
*/
cpumask_var_t rto_mask;
atomic_t rto_count;
-#ifdef CONFIG_SMP
struct cpupri cpupri;
-#endif
};
/*
@@ -437,7 +435,7 @@ struct root_domain {
*/
static struct root_domain def_root_domain;
-#endif
+#endif /* CONFIG_SMP */
/*
* This is the main, per-CPU runqueue data structure.
@@ -488,11 +486,12 @@ struct rq {
*/
unsigned long nr_uninterruptible;
- struct task_struct *curr, *idle;
+ struct task_struct *curr, *idle, *stop;
unsigned long next_balance;
struct mm_struct *prev_mm;
u64 clock;
+ u64 clock_task;
atomic_t nr_iowait;
@@ -520,6 +519,10 @@ struct rq {
u64 avg_idle;
#endif
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+ u64 prev_irq_time;
+#endif
+
/* calc_load related fields */
unsigned long calc_load_update;
long calc_load_active;
@@ -643,10 +646,22 @@ static inline struct task_group *task_group(struct task_struct *p)
#endif /* CONFIG_CGROUP_SCHED */
+static u64 irq_time_cpu(int cpu);
+static void sched_irq_time_avg_update(struct rq *rq, u64 irq_time);
+
inline void update_rq_clock(struct rq *rq)
{
- if (!rq->skip_clock_update)
- rq->clock = sched_clock_cpu(cpu_of(rq));
+ if (!rq->skip_clock_update) {
+ int cpu = cpu_of(rq);
+ u64 irq_time;
+
+ rq->clock = sched_clock_cpu(cpu);
+ irq_time = irq_time_cpu(cpu);
+ if (rq->clock - irq_time > rq->clock_task)
+ rq->clock_task = rq->clock - irq_time;
+
+ sched_irq_time_avg_update(rq, irq_time);
+ }
}
/*
@@ -723,7 +738,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64];
- char *cmp = buf;
+ char *cmp;
int neg = 0;
int i;
@@ -734,6 +749,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
return -EFAULT;
buf[cnt] = 0;
+ cmp = strstrip(buf);
if (strncmp(buf, "NO_", 3) == 0) {
neg = 1;
@@ -741,9 +757,7 @@ sched_feat_write(struct file *filp, const char __user *ubuf,
}
for (i = 0; sched_feat_names[i]; i++) {
- int len = strlen(sched_feat_names[i]);
-
- if (strncmp(cmp, sched_feat_names[i], len) == 0) {
+ if (strcmp(cmp, sched_feat_names[i]) == 0) {
if (neg)
sysctl_sched_features &= ~(1UL << i);
else
@@ -1294,6 +1308,10 @@ static void resched_task(struct task_struct *p)
static void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
{
}
+
+static void sched_avg_update(struct rq *rq)
+{
+}
#endif /* CONFIG_SMP */
#if BITS_PER_LONG == 32
@@ -1836,7 +1854,7 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
static const struct sched_class rt_sched_class;
-#define sched_class_highest (&rt_sched_class)
+#define sched_class_highest (&stop_sched_class)
#define for_each_class(class) \
for (class = sched_class_highest; class; class = class->next)
@@ -1854,12 +1872,6 @@ static void dec_nr_running(struct rq *rq)
static void set_load_weight(struct task_struct *p)
{
- if (task_has_rt_policy(p)) {
- p->se.load.weight = 0;
- p->se.load.inv_weight = WMULT_CONST;
- return;
- }
-
/*
* SCHED_IDLE tasks get minimal weight:
*/
@@ -1913,13 +1925,132 @@ static void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
dec_nr_running(rq);
}
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+
+/*
+ * There are no locks covering percpu hardirq/softirq time.
+ * They are only modified in account_system_vtime, on corresponding CPU
+ * with interrupts disabled. So, writes are safe.
+ * They are read and saved off onto struct rq in update_rq_clock().
+ * This may result in other CPU reading this CPU's irq time and can
+ * race with irq/account_system_vtime on this CPU. We would either get old
+ * or new value (or semi updated value on 32 bit) with a side effect of
+ * accounting a slice of irq time to wrong task when irq is in progress
+ * while we read rq->clock. That is a worthy compromise in place of having
+ * locks on each irq in account_system_time.
+ */
+static DEFINE_PER_CPU(u64, cpu_hardirq_time);
+static DEFINE_PER_CPU(u64, cpu_softirq_time);
+
+static DEFINE_PER_CPU(u64, irq_start_time);
+static int sched_clock_irqtime;
+
+void enable_sched_clock_irqtime(void)
+{
+ sched_clock_irqtime = 1;
+}
+
+void disable_sched_clock_irqtime(void)
+{
+ sched_clock_irqtime = 0;
+}
+
+static u64 irq_time_cpu(int cpu)
+{
+ if (!sched_clock_irqtime)
+ return 0;
+
+ return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
+}
+
+void account_system_vtime(struct task_struct *curr)
+{
+ unsigned long flags;
+ int cpu;
+ u64 now, delta;
+
+ if (!sched_clock_irqtime)
+ return;
+
+ local_irq_save(flags);
+
+ cpu = smp_processor_id();
+ now = sched_clock_cpu(cpu);
+ delta = now - per_cpu(irq_start_time, cpu);
+ per_cpu(irq_start_time, cpu) = now;
+ /*
+ * We do not account for softirq time from ksoftirqd here.
+ * We want to continue accounting softirq time to ksoftirqd thread
+ * in that case, so as not to confuse scheduler with a special task
+ * that do not consume any time, but still wants to run.
+ */
+ if (hardirq_count())
+ per_cpu(cpu_hardirq_time, cpu) += delta;
+ else if (in_serving_softirq() && !(curr->flags & PF_KSOFTIRQD))
+ per_cpu(cpu_softirq_time, cpu) += delta;
+
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(account_system_vtime);
+
+static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time)
+{
+ if (sched_clock_irqtime && sched_feat(NONIRQ_POWER)) {
+ u64 delta_irq = curr_irq_time - rq->prev_irq_time;
+ rq->prev_irq_time = curr_irq_time;
+ sched_rt_avg_update(rq, delta_irq);
+ }
+}
+
+#else
+
+static u64 irq_time_cpu(int cpu)
+{
+ return 0;
+}
+
+static void sched_irq_time_avg_update(struct rq *rq, u64 curr_irq_time) { }
+
+#endif
+
#include "sched_idletask.c"
#include "sched_fair.c"
#include "sched_rt.c"
+#include "sched_stoptask.c"
#ifdef CONFIG_SCHED_DEBUG
# include "sched_debug.c"
#endif
+void sched_set_stop_task(int cpu, struct task_struct *stop)
+{
+ struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
+ struct task_struct *old_stop = cpu_rq(cpu)->stop;
+
+ if (stop) {
+ /*
+ * Make it appear like a SCHED_FIFO task, its something
+ * userspace knows about and won't get confused about.
+ *
+ * Also, it will make PI more or less work without too
+ * much confusion -- but then, stop work should not
+ * rely on PI working anyway.
+ */
+ sched_setscheduler_nocheck(stop, SCHED_FIFO, &param);
+
+ stop->sched_class = &stop_sched_class;
+ }
+
+ cpu_rq(cpu)->stop = stop;
+
+ if (old_stop) {
+ /*
+ * Reset it back to a normal scheduling class so that
+ * it can die in pieces.
+ */
+ old_stop->sched_class = &rt_sched_class;
+ }
+}
+
/*
* __normal_prio - return the priority that is based on the static prio
*/
@@ -1999,6 +2130,9 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
if (p->sched_class != &fair_sched_class)
return 0;
+ if (unlikely(p->policy == SCHED_IDLE))
+ return 0;
+
/*
* Buddy candidates are cache hot:
*/
@@ -2848,14 +2982,14 @@ context_switch(struct rq *rq, struct task_struct *prev,
*/
arch_start_context_switch(prev);
- if (likely(!mm)) {
+ if (!mm) {
next->active_mm = oldmm;
atomic_inc(&oldmm->mm_count);
enter_lazy_tlb(oldmm, next);
} else
switch_mm(oldmm, mm, next);
- if (likely(!prev->mm)) {
+ if (!prev->mm) {
prev->active_mm = NULL;
rq->prev_mm = oldmm;
}
@@ -3182,6 +3316,8 @@ static void update_cpu_load(struct rq *this_rq)
this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
}
+
+ sched_avg_update(this_rq);
}
static void update_cpu_load_active(struct rq *this_rq)
@@ -3242,7 +3378,7 @@ static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
if (task_current(rq, p)) {
update_rq_clock(rq);
- ns = rq->clock - p->se.exec_start;
+ ns = rq->clock_task - p->se.exec_start;
if ((s64)ns < 0)
ns = 0;
}
@@ -3391,7 +3527,7 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
tmp = cputime_to_cputime64(cputime);
if (hardirq_count() - hardirq_offset)
cpustat->irq = cputime64_add(cpustat->irq, tmp);
- else if (softirq_count())
+ else if (in_serving_softirq())
cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
else
cpustat->system = cputime64_add(cpustat->system, tmp);
@@ -3507,9 +3643,9 @@ void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
rtime = nsecs_to_cputime(p->se.sum_exec_runtime);
if (total) {
- u64 temp;
+ u64 temp = rtime;
- temp = (u64)(rtime * utime);
+ temp *= utime;
do_div(temp, total);
utime = (cputime_t)temp;
} else
@@ -3540,9 +3676,9 @@ void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
rtime = nsecs_to_cputime(cputime.sum_exec_runtime);
if (total) {
- u64 temp;
+ u64 temp = rtime;
- temp = (u64)(rtime * cputime.utime);
+ temp *= cputime.utime;
do_div(temp, total);
utime = (cputime_t)temp;
} else
@@ -3578,7 +3714,7 @@ void scheduler_tick(void)
curr->sched_class->task_tick(rq, curr, 0);
raw_spin_unlock(&rq->lock);
- perf_event_task_tick(curr);
+ perf_event_task_tick();
#ifdef CONFIG_SMP
rq->idle_at_tick = idle_cpu(cpu);
@@ -3717,17 +3853,13 @@ pick_next_task(struct rq *rq)
return p;
}
- class = sched_class_highest;
- for ( ; ; ) {
+ for_each_class(class) {
p = class->pick_next_task(rq);
if (p)
return p;
- /*
- * Will never be NULL as the idle class always
- * returns a non-NULL p:
- */
- class = class->next;
}
+
+ BUG(); /* the idle class will always have a runnable task */
}
/*
@@ -3865,8 +3997,16 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
/*
* Owner changed, break to re-assess state.
*/
- if (lock->owner != owner)
+ if (lock->owner != owner) {
+ /*
+ * If the lock has switched to a different owner,
+ * we likely have heavy contention. Return 0 to quit
+ * optimistic spinning and not contend further:
+ */
+ if (lock->owner)
+ return 0;
break;
+ }
/*
* Is that owner really running on that cpu?
@@ -4344,6 +4484,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
rq = task_rq_lock(p, &flags);
+ trace_sched_pi_setprio(p, prio);
oldprio = p->prio;
prev_class = p->sched_class;
on_rq = p->se.on_rq;
@@ -4631,7 +4772,7 @@ recheck:
}
if (user) {
- retval = security_task_setscheduler(p, policy, param);
+ retval = security_task_setscheduler(p);
if (retval)
return retval;
}
@@ -4647,6 +4788,15 @@ recheck:
*/
rq = __task_rq_lock(p);
+ /*
+ * Changing the policy of the stop threads its a very bad idea
+ */
+ if (p == rq->stop) {
+ __task_rq_unlock(rq);
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+ return -EINVAL;
+ }
+
#ifdef CONFIG_RT_GROUP_SCHED
if (user) {
/*
@@ -4873,13 +5023,13 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
goto out_unlock;
- retval = security_task_setscheduler(p, 0, NULL);
+ retval = security_task_setscheduler(p);
if (retval)
goto out_unlock;
cpuset_cpus_allowed(p, cpus_allowed);
cpumask_and(new_mask, in_mask, cpus_allowed);
- again:
+again:
retval = set_cpus_allowed_ptr(p, new_mask);
if (!retval) {
@@ -5323,7 +5473,19 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
idle->se.exec_start = sched_clock();
cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
+ /*
+ * We're having a chicken and egg problem, even though we are
+ * holding rq->lock, the cpu isn't yet set to this cpu so the
+ * lockdep check in task_group() will fail.
+ *
+ * Similar case to sched_fork(). / Alternatively we could
+ * use task_rq_lock() here and obtain the other rq->lock.
+ *
+ * Silence PROVE_RCU
+ */
+ rcu_read_lock();
__set_task_cpu(idle, cpu);
+ rcu_read_unlock();
rq->curr = rq->idle = idle;
#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
@@ -6500,6 +6662,7 @@ struct s_data {
cpumask_var_t nodemask;
cpumask_var_t this_sibling_map;
cpumask_var_t this_core_map;
+ cpumask_var_t this_book_map;
cpumask_var_t send_covered;
cpumask_var_t tmpmask;
struct sched_group **sched_group_nodes;
@@ -6511,6 +6674,7 @@ enum s_alloc {
sa_rootdomain,
sa_tmpmask,
sa_send_covered,
+ sa_this_book_map,
sa_this_core_map,
sa_this_sibling_map,
sa_nodemask,
@@ -6546,31 +6710,48 @@ cpu_to_cpu_group(int cpu, const struct cpumask *cpu_map,
#ifdef CONFIG_SCHED_MC
static DEFINE_PER_CPU(struct static_sched_domain, core_domains);
static DEFINE_PER_CPU(struct static_sched_group, sched_group_core);
-#endif /* CONFIG_SCHED_MC */
-#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
static int
cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
struct sched_group **sg, struct cpumask *mask)
{
int group;
-
+#ifdef CONFIG_SCHED_SMT
cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
group = cpumask_first(mask);
+#else
+ group = cpu;
+#endif
if (sg)
*sg = &per_cpu(sched_group_core, group).sg;
return group;
}
-#elif defined(CONFIG_SCHED_MC)
+#endif /* CONFIG_SCHED_MC */
+
+/*
+ * book sched-domains:
+ */
+#ifdef CONFIG_SCHED_BOOK
+static DEFINE_PER_CPU(struct static_sched_domain, book_domains);
+static DEFINE_PER_CPU(struct static_sched_group, sched_group_book);
+
static int
-cpu_to_core_group(int cpu, const struct cpumask *cpu_map,
- struct sched_group **sg, struct cpumask *unused)
+cpu_to_book_group(int cpu, const struct cpumask *cpu_map,
+ struct sched_group **sg, struct cpumask *mask)
{
+ int group = cpu;
+#ifdef CONFIG_SCHED_MC
+ cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
+ group = cpumask_first(mask);
+#elif defined(CONFIG_SCHED_SMT)
+ cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
+ group = cpumask_first(mask);
+#endif
if (sg)
- *sg = &per_cpu(sched_group_core, cpu).sg;
- return cpu;
+ *sg = &per_cpu(sched_group_book, group).sg;
+ return group;
}
-#endif
+#endif /* CONFIG_SCHED_BOOK */
static DEFINE_PER_CPU(struct static_sched_domain, phys_domains);
static DEFINE_PER_CPU(struct static_sched_group, sched_group_phys);
@@ -6580,7 +6761,10 @@ cpu_to_phys_group(int cpu, const struct cpumask *cpu_map,
struct sched_group **sg, struct cpumask *mask)
{
int group;
-#ifdef CONFIG_SCHED_MC
+#ifdef CONFIG_SCHED_BOOK
+ cpumask_and(mask, cpu_book_mask(cpu), cpu_map);
+ group = cpumask_first(mask);
+#elif defined(CONFIG_SCHED_MC)
cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
group = cpumask_first(mask);
#elif defined(CONFIG_SCHED_SMT)
@@ -6841,6 +7025,9 @@ SD_INIT_FUNC(CPU)
#ifdef CONFIG_SCHED_MC
SD_INIT_FUNC(MC)
#endif
+#ifdef CONFIG_SCHED_BOOK
+ SD_INIT_FUNC(BOOK)
+#endif
static int default_relax_domain_level = -1;
@@ -6890,6 +7077,8 @@ static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
free_cpumask_var(d->tmpmask); /* fall through */
case sa_send_covered:
free_cpumask_var(d->send_covered); /* fall through */
+ case sa_this_book_map:
+ free_cpumask_var(d->this_book_map); /* fall through */
case sa_this_core_map:
free_cpumask_var(d->this_core_map); /* fall through */
case sa_this_sibling_map:
@@ -6936,8 +7125,10 @@ static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
return sa_nodemask;
if (!alloc_cpumask_var(&d->this_core_map, GFP_KERNEL))
return sa_this_sibling_map;
- if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL))
+ if (!alloc_cpumask_var(&d->this_book_map, GFP_KERNEL))
return sa_this_core_map;
+ if (!alloc_cpumask_var(&d->send_covered, GFP_KERNEL))
+ return sa_this_book_map;
if (!alloc_cpumask_var(&d->tmpmask, GFP_KERNEL))
return sa_send_covered;
d->rd = alloc_rootdomain();
@@ -6995,6 +7186,23 @@ static struct sched_domain *__build_cpu_sched_domain(struct s_data *d,
return sd;
}
+static struct sched_domain *__build_book_sched_domain(struct s_data *d,
+ const struct cpumask *cpu_map, struct sched_domain_attr *attr,
+ struct sched_domain *parent, int i)
+{
+ struct sched_domain *sd = parent;
+#ifdef CONFIG_SCHED_BOOK
+ sd = &per_cpu(book_domains, i).sd;
+ SD_INIT(sd, BOOK);
+ set_domain_attribute(sd, attr);
+ cpumask_and(sched_domain_span(sd), cpu_map, cpu_book_mask(i));
+ sd->parent = parent;
+ parent->child = sd;
+ cpu_to_book_group(i, cpu_map, &sd->groups, d->tmpmask);
+#endif
+ return sd;
+}
+
static struct sched_domain *__build_mc_sched_domain(struct s_data *d,
const struct cpumask *cpu_map, struct sched_domain_attr *attr,
struct sched_domain *parent, int i)
@@ -7052,6 +7260,15 @@ static void build_sched_groups(struct s_data *d, enum sched_domain_level l,
d->send_covered, d->tmpmask);
break;
#endif
+#ifdef CONFIG_SCHED_BOOK
+ case SD_LV_BOOK: /* set up book groups */
+ cpumask_and(d->this_book_map, cpu_map, cpu_book_mask(cpu));
+ if (cpu == cpumask_first(d->this_book_map))
+ init_sched_build_groups(d->this_book_map, cpu_map,
+ &cpu_to_book_group,
+ d->send_covered, d->tmpmask);
+ break;
+#endif
case SD_LV_CPU: /* set up physical groups */
cpumask_and(d->nodemask, cpumask_of_node(cpu), cpu_map);
if (!cpumask_empty(d->nodemask))
@@ -7099,12 +7316,14 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
sd = __build_numa_sched_domains(&d, cpu_map, attr, i);
sd = __build_cpu_sched_domain(&d, cpu_map, attr, sd, i);
+ sd = __build_book_sched_domain(&d, cpu_map, attr, sd, i);
sd = __build_mc_sched_domain(&d, cpu_map, attr, sd, i);
sd = __build_smt_sched_domain(&d, cpu_map, attr, sd, i);
}
for_each_cpu(i, cpu_map) {
build_sched_groups(&d, SD_LV_SIBLING, cpu_map, i);
+ build_sched_groups(&d, SD_LV_BOOK, cpu_map, i);
build_sched_groups(&d, SD_LV_MC, cpu_map, i);
}
@@ -7135,6 +7354,12 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
init_sched_groups_power(i, sd);
}
#endif
+#ifdef CONFIG_SCHED_BOOK
+ for_each_cpu(i, cpu_map) {
+ sd = &per_cpu(book_domains, i).sd;
+ init_sched_groups_power(i, sd);
+ }
+#endif
for_each_cpu(i, cpu_map) {
sd = &per_cpu(phys_domains, i).sd;
@@ -7160,6 +7385,8 @@ static int __build_sched_domains(const struct cpumask *cpu_map,
sd = &per_cpu(cpu_domains, i).sd;
#elif defined(CONFIG_SCHED_MC)
sd = &per_cpu(core_domains, i).sd;
+#elif defined(CONFIG_SCHED_BOOK)
+ sd = &per_cpu(book_domains, i).sd;
#else
sd = &per_cpu(phys_domains, i).sd;
#endif
@@ -8064,9 +8291,9 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
return 1;
- err_free_rq:
+err_free_rq:
kfree(cfs_rq);
- err:
+err:
return 0;
}
@@ -8154,9 +8381,9 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
return 1;
- err_free_rq:
+err_free_rq:
kfree(rt_rq);
- err:
+err:
return 0;
}
@@ -8514,7 +8741,7 @@ static int tg_set_bandwidth(struct task_group *tg,
raw_spin_unlock(&rt_rq->rt_runtime_lock);
}
raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
- unlock:
+unlock:
read_unlock(&tasklist_lock);
mutex_unlock(&rt_constraints_mutex);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-26 07:41:20 +0000