From a57eb940d130477a799dfb24a570ee04979c0f7f Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 29 Jun 2010 16:49:16 -0700 Subject: rcu: Add a TINY_PREEMPT_RCU MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Implement a small-memory-footprint uniprocessor-only implementation of preemptible RCU. This implementation uses but a single blocked-tasks list rather than the combinatorial number used per leaf rcu_node by TREE_PREEMPT_RCU, which reduces memory consumption and greatly simplifies processing. This version also takes advantage of uniprocessor execution to accelerate grace periods in the case where there are no readers. The general design is otherwise broadly similar to that of TREE_PREEMPT_RCU. This implementation is a step towards having RCU implementation driven off of the SMP and PREEMPT kernel configuration variables, which can happen once this implementation has accumulated sufficient experience. Removed ACCESS_ONCE() from __rcu_read_unlock() and added barrier() as suggested by Steve Rostedt in order to avoid the compiler-reordering issue noted by Mathieu Desnoyers (http://lkml.org/lkml/2010/8/16/183). As can be seen below, CONFIG_TINY_PREEMPT_RCU represents almost 5Kbyte savings compared to CONFIG_TREE_PREEMPT_RCU. Of course, for non-real-time workloads, CONFIG_TINY_RCU is even better. CONFIG_TREE_PREEMPT_RCU text data bss dec filename 13 0 0 13 kernel/rcupdate.o 6170 825 28 7023 kernel/rcutree.o ---- 7026 Total CONFIG_TINY_PREEMPT_RCU text data bss dec filename 13 0 0 13 kernel/rcupdate.o 2081 81 8 2170 kernel/rcutiny.o ---- 2183 Total CONFIG_TINY_RCU (non-preemptible) text data bss dec filename 13 0 0 13 kernel/rcupdate.o 719 25 0 744 kernel/rcutiny.o --- 757 Total Requested-by: Loïc Minier Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 126 ++++++++++++++++++++++++++++++++++-------------- 1 file changed, 89 insertions(+), 37 deletions(-) (limited to 'include/linux/rcutiny.h') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index e2e893144a8..4cc5eba4161 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -29,66 +29,51 @@ void rcu_sched_qs(int cpu); void rcu_bh_qs(int cpu); -static inline void rcu_note_context_switch(int cpu) -{ - rcu_sched_qs(cpu); -} +#ifdef CONFIG_TINY_RCU #define __rcu_read_lock() preempt_disable() #define __rcu_read_unlock() preempt_enable() +#else /* #ifdef CONFIG_TINY_RCU */ +void __rcu_read_lock(void); +void __rcu_read_unlock(void); +#endif /* #else #ifdef CONFIG_TINY_RCU */ #define __rcu_read_lock_bh() local_bh_disable() #define __rcu_read_unlock_bh() local_bh_enable() -#define call_rcu_sched call_rcu +extern void call_rcu_sched(struct rcu_head *head, + void (*func)(struct rcu_head *rcu)); #define rcu_init_sched() do { } while (0) -extern void rcu_check_callbacks(int cpu, int user); -static inline int rcu_needs_cpu(int cpu) -{ - return 0; -} +extern void synchronize_sched(void); -/* - * Return the number of grace periods. - */ -static inline long rcu_batches_completed(void) -{ - return 0; -} +#ifdef CONFIG_TINY_RCU -/* - * Return the number of bottom-half grace periods. - */ -static inline long rcu_batches_completed_bh(void) -{ - return 0; -} +#define call_rcu call_rcu_sched -static inline void rcu_force_quiescent_state(void) +static inline void synchronize_rcu(void) { + synchronize_sched(); } -static inline void rcu_bh_force_quiescent_state(void) +static inline void synchronize_rcu_expedited(void) { + synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */ } -static inline void rcu_sched_force_quiescent_state(void) +static inline void rcu_barrier(void) { + rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */ } -extern void synchronize_sched(void); +#else /* #ifdef CONFIG_TINY_RCU */ -static inline void synchronize_rcu(void) -{ - synchronize_sched(); -} +void synchronize_rcu(void); +void rcu_barrier(void); +void synchronize_rcu_expedited(void); -static inline void synchronize_rcu_bh(void) -{ - synchronize_sched(); -} +#endif /* #else #ifdef CONFIG_TINY_RCU */ -static inline void synchronize_rcu_expedited(void) +static inline void synchronize_rcu_bh(void) { synchronize_sched(); } @@ -117,15 +102,82 @@ static inline void rcu_exit_nohz(void) #endif /* #else #ifdef CONFIG_NO_HZ */ +#ifdef CONFIG_TINY_RCU + +static inline void rcu_preempt_note_context_switch(void) +{ +} + static inline void exit_rcu(void) { } +static inline int rcu_needs_cpu(int cpu) +{ + return 0; +} + static inline int rcu_preempt_depth(void) { return 0; } +#else /* #ifdef CONFIG_TINY_RCU */ + +void rcu_preempt_note_context_switch(void); +extern void exit_rcu(void); +int rcu_preempt_needs_cpu(void); + +static inline int rcu_needs_cpu(int cpu) +{ + return rcu_preempt_needs_cpu(); +} + +/* + * Defined as macro as it is a very low level header + * included from areas that don't even know about current + * FIXME: combine with include/linux/rcutree.h into rcupdate.h. + */ +#define rcu_preempt_depth() (current->rcu_read_lock_nesting) + +#endif /* #else #ifdef CONFIG_TINY_RCU */ + +static inline void rcu_note_context_switch(int cpu) +{ + rcu_sched_qs(cpu); + rcu_preempt_note_context_switch(); +} + +extern void rcu_check_callbacks(int cpu, int user); + +/* + * Return the number of grace periods. + */ +static inline long rcu_batches_completed(void) +{ + return 0; +} + +/* + * Return the number of bottom-half grace periods. + */ +static inline long rcu_batches_completed_bh(void) +{ + return 0; +} + +static inline void rcu_force_quiescent_state(void) +{ +} + +static inline void rcu_bh_force_quiescent_state(void) +{ +} + +static inline void rcu_sched_force_quiescent_state(void) +{ +} + #ifdef CONFIG_DEBUG_LOCK_ALLOC extern int rcu_scheduler_active __read_mostly; -- cgit v1.2.3-70-g09d2 From 53d84e004d5e8c018be395c4330dc72fd60bd13e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 10 Aug 2010 14:28:53 -0700 Subject: rcu: permit suppressing current grace period's CPU stall warnings When using a kernel debugger, a long sojourn in the debugger can get you lots of RCU CPU stall warnings once you resume. This might not be helpful, especially if you are using the system console. This patch therefore allows RCU CPU stall warnings to be suppressed, but only for the duration of the current set of grace periods. This differs from Jason's original patch in that it adds support for tiny RCU and preemptible RCU, and uses a slightly different method for suppressing the RCU CPU stall warning messages. Signed-off-by: Jason Wessel Signed-off-by: Paul E. McKenney Tested-by: Jason Wessel --- include/linux/rcutiny.h | 4 ++++ include/linux/rcutree.h | 1 + kernel/rcutree.c | 20 ++++++++++++++++++++ kernel/rcutree.h | 1 + kernel/rcutree_plugin.h | 18 ++++++++++++++++++ 5 files changed, 44 insertions(+) (limited to 'include/linux/rcutiny.h') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 4cc5eba4161..3fa179784e1 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -178,6 +178,10 @@ static inline void rcu_sched_force_quiescent_state(void) { } +static inline void rcu_cpu_stall_reset(void) +{ +} + #ifdef CONFIG_DEBUG_LOCK_ALLOC extern int rcu_scheduler_active __read_mostly; diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index c13b85dd22b..0726809497b 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -36,6 +36,7 @@ extern void rcu_sched_qs(int cpu); extern void rcu_bh_qs(int cpu); extern void rcu_note_context_switch(int cpu); extern int rcu_needs_cpu(int cpu); +extern void rcu_cpu_stall_reset(void); #ifdef CONFIG_TREE_PREEMPT_RCU diff --git a/kernel/rcutree.c b/kernel/rcutree.c index ff214118e4b..42140a860bb 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -565,6 +565,22 @@ static int rcu_panic(struct notifier_block *this, unsigned long ev, void *ptr) return NOTIFY_DONE; } +/** + * rcu_cpu_stall_reset - prevent further stall warnings in current grace period + * + * Set the stall-warning timeout way off into the future, thus preventing + * any RCU CPU stall-warning messages from appearing in the current set of + * RCU grace periods. + * + * The caller must disable hard irqs. + */ +void rcu_cpu_stall_reset(void) +{ + rcu_sched_state.jiffies_stall = jiffies + ULONG_MAX / 2; + rcu_bh_state.jiffies_stall = jiffies + ULONG_MAX / 2; + rcu_preempt_stall_reset(); +} + static struct notifier_block rcu_panic_block = { .notifier_call = rcu_panic, }; @@ -584,6 +600,10 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp) { } +void rcu_cpu_stall_reset(void) +{ +} + static void __init check_cpu_stall_init(void) { } diff --git a/kernel/rcutree.h b/kernel/rcutree.h index bb4d08695c4..7abd439a757 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -372,6 +372,7 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, #ifdef CONFIG_RCU_CPU_STALL_DETECTOR static void rcu_print_detail_task_stall(struct rcu_state *rsp); static void rcu_print_task_stall(struct rcu_node *rnp); +static void rcu_preempt_stall_reset(void); #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 63bb7714fde..561410f70d4 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -417,6 +417,16 @@ static void rcu_print_task_stall(struct rcu_node *rnp) } } +/* + * Suppress preemptible RCU's CPU stall warnings by pushing the + * time of the next stall-warning message comfortably far into the + * future. + */ +static void rcu_preempt_stall_reset(void) +{ + rcu_preempt_state.jiffies_stall = jiffies + ULONG_MAX / 2; +} + #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ /* @@ -867,6 +877,14 @@ static void rcu_print_task_stall(struct rcu_node *rnp) { } +/* + * Because preemptible RCU does not exist, there is no need to suppress + * its CPU stall warnings. + */ +static void rcu_preempt_stall_reset(void) +{ +} + #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ /* -- cgit v1.2.3-70-g09d2 From a3dc3fb161f9b4066c0fce22db72638af8baf83b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 13 Aug 2010 16:16:25 -0700 Subject: rcu: repair code-duplication FIXMEs Combine the duplicate definitions of ULONG_CMP_GE(), ULONG_CMP_LT(), and rcu_preempt_depth() into include/linux/rcupdate.h. Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 15 +++++++++++++++ include/linux/rcutiny.h | 7 ------- include/linux/rcutree.h | 6 ------ kernel/rcutiny_plugin.h | 4 ---- kernel/rcutree.h | 3 --- 5 files changed, 15 insertions(+), 20 deletions(-) (limited to 'include/linux/rcutiny.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index d7af96ef6fc..325bad7bbca 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -47,6 +47,9 @@ extern int rcutorture_runnable; /* for sysctl */ #endif /* #ifdef CONFIG_RCU_TORTURE_TEST */ +#define ULONG_CMP_GE(a, b) (ULONG_MAX / 2 >= (a) - (b)) +#define ULONG_CMP_LT(a, b) (ULONG_MAX / 2 < (a) - (b)) + /** * struct rcu_head - callback structure for use with RCU * @next: next update requests in a list @@ -66,6 +69,18 @@ extern int sched_expedited_torture_stats(char *page); /* Internal to kernel */ extern void rcu_init(void); +#ifdef CONFIG_PREEMPT_RCU + +/* + * Defined as a macro as it is a very low level header included from + * areas that don't even know about current. This gives the rcu_read_lock() + * nesting depth, but makes sense only if CONFIG_PREEMPT_RCU -- in other + * types of kernel builds, the rcu_read_lock() nesting depth is unknowable. + */ +#define rcu_preempt_depth() (current->rcu_read_lock_nesting) + +#endif /* #ifdef CONFIG_PREEMPT_RCU */ + #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) #include #elif defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 3fa179784e1..c6b11dc5ba0 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -133,13 +133,6 @@ static inline int rcu_needs_cpu(int cpu) return rcu_preempt_needs_cpu(); } -/* - * Defined as macro as it is a very low level header - * included from areas that don't even know about current - * FIXME: combine with include/linux/rcutree.h into rcupdate.h. - */ -#define rcu_preempt_depth() (current->rcu_read_lock_nesting) - #endif /* #else #ifdef CONFIG_TINY_RCU */ static inline void rcu_note_context_switch(int cpu) diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 0726809497b..54a20c11f98 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -45,12 +45,6 @@ extern void __rcu_read_unlock(void); extern void synchronize_rcu(void); extern void exit_rcu(void); -/* - * Defined as macro as it is a very low level header - * included from areas that don't even know about current - */ -#define rcu_preempt_depth() (current->rcu_read_lock_nesting) - #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ static inline void __rcu_read_lock(void) diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h index e6bc1b447c6..c5bea1137dc 100644 --- a/kernel/rcutiny_plugin.h +++ b/kernel/rcutiny_plugin.h @@ -26,10 +26,6 @@ #include -/* FIXME: merge with definitions in kernel/rcutree.h. */ -#define ULONG_CMP_GE(a, b) (ULONG_MAX / 2 >= (a) - (b)) -#define ULONG_CMP_LT(a, b) (ULONG_MAX / 2 < (a) - (b)) - /* Global control variables for preemptible RCU. */ struct rcu_preempt_ctrlblk { struct rcu_ctrlblk rcb; /* curtail: ->next ptr of last CB for GP. */ diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 7abd439a757..7918ba61873 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -272,9 +272,6 @@ struct rcu_data { #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ -#define ULONG_CMP_GE(a, b) (ULONG_MAX / 2 >= (a) - (b)) -#define ULONG_CMP_LT(a, b) (ULONG_MAX / 2 < (a) - (b)) - /* * RCU global state, including node hierarchy. This hierarchy is * represented in "heap" form in a dense array. The root (first level) -- cgit v1.2.3-70-g09d2 From 7b0b759b65247cbc66384a912be9acf8d4800636 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 17 Aug 2010 14:18:46 -0700 Subject: rcu: combine duplicate code, courtesy of CONFIG_PREEMPT_RCU The CONFIG_PREEMPT_RCU kernel configuration parameter was recently re-introduced, but as an indication of the type of RCU (preemptible vs. non-preemptible) instead of as selecting a given implementation. This commit uses CONFIG_PREEMPT_RCU to combine duplicate code from include/linux/rcutiny.h and include/linux/rcutree.h into include/linux/rcupdate.h. This commit also combines a few other pieces of duplicate code that have accumulated. Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 75 ++++++++++++++++++++++++++++++++++++++++++++++-- include/linux/rcutiny.h | 51 -------------------------------- include/linux/rcutree.h | 50 -------------------------------- kernel/rcutree_plugin.h | 9 ------ 4 files changed, 72 insertions(+), 113 deletions(-) (limited to 'include/linux/rcutiny.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 325bad7bbca..89414d67d96 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -61,16 +61,30 @@ struct rcu_head { }; /* Exported common interfaces */ +extern void call_rcu_sched(struct rcu_head *head, + void (*func)(struct rcu_head *rcu)); +extern void synchronize_sched(void); extern void rcu_barrier_bh(void); extern void rcu_barrier_sched(void); extern void synchronize_sched_expedited(void); extern int sched_expedited_torture_stats(char *page); -/* Internal to kernel */ -extern void rcu_init(void); +static inline void __rcu_read_lock_bh(void) +{ + local_bh_disable(); +} + +static inline void __rcu_read_unlock_bh(void) +{ + local_bh_enable(); +} #ifdef CONFIG_PREEMPT_RCU +extern void __rcu_read_lock(void); +extern void __rcu_read_unlock(void); +void synchronize_rcu(void); + /* * Defined as a macro as it is a very low level header included from * areas that don't even know about current. This gives the rcu_read_lock() @@ -79,7 +93,53 @@ extern void rcu_init(void); */ #define rcu_preempt_depth() (current->rcu_read_lock_nesting) -#endif /* #ifdef CONFIG_PREEMPT_RCU */ +#else /* #ifdef CONFIG_PREEMPT_RCU */ + +static inline void __rcu_read_lock(void) +{ + preempt_disable(); +} + +static inline void __rcu_read_unlock(void) +{ + preempt_enable(); +} + +static inline void synchronize_rcu(void) +{ + synchronize_sched(); +} + +static inline int rcu_preempt_depth(void) +{ + return 0; +} + +#endif /* #else #ifdef CONFIG_PREEMPT_RCU */ + +/* Internal to kernel */ +extern void rcu_init(void); +extern void rcu_sched_qs(int cpu); +extern void rcu_bh_qs(int cpu); +extern void rcu_check_callbacks(int cpu, int user); +struct notifier_block; + +#ifdef CONFIG_NO_HZ + +extern void rcu_enter_nohz(void); +extern void rcu_exit_nohz(void); + +#else /* #ifdef CONFIG_NO_HZ */ + +static inline void rcu_enter_nohz(void) +{ +} + +static inline void rcu_exit_nohz(void) +{ +} + +#endif /* #else #ifdef CONFIG_NO_HZ */ #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) #include @@ -626,6 +686,8 @@ struct rcu_synchronize { extern void wakeme_after_rcu(struct rcu_head *head); +#ifdef CONFIG_PREEMPT_RCU + /** * call_rcu() - Queue an RCU callback for invocation after a grace period. * @head: structure to be used for queueing the RCU updates. @@ -642,6 +704,13 @@ extern void wakeme_after_rcu(struct rcu_head *head); extern void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *head)); +#else /* #ifdef CONFIG_PREEMPT_RCU */ + +/* In classic RCU, call_rcu() is just call_rcu_sched(). */ +#define call_rcu call_rcu_sched + +#endif /* #else #ifdef CONFIG_PREEMPT_RCU */ + /** * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period. * @head: structure to be used for queueing the RCU updates. diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index c6b11dc5ba0..13877cb93a6 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -27,34 +27,10 @@ #include -void rcu_sched_qs(int cpu); -void rcu_bh_qs(int cpu); - -#ifdef CONFIG_TINY_RCU -#define __rcu_read_lock() preempt_disable() -#define __rcu_read_unlock() preempt_enable() -#else /* #ifdef CONFIG_TINY_RCU */ -void __rcu_read_lock(void); -void __rcu_read_unlock(void); -#endif /* #else #ifdef CONFIG_TINY_RCU */ -#define __rcu_read_lock_bh() local_bh_disable() -#define __rcu_read_unlock_bh() local_bh_enable() -extern void call_rcu_sched(struct rcu_head *head, - void (*func)(struct rcu_head *rcu)); - #define rcu_init_sched() do { } while (0) -extern void synchronize_sched(void); - #ifdef CONFIG_TINY_RCU -#define call_rcu call_rcu_sched - -static inline void synchronize_rcu(void) -{ - synchronize_sched(); -} - static inline void synchronize_rcu_expedited(void) { synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */ @@ -67,7 +43,6 @@ static inline void rcu_barrier(void) #else /* #ifdef CONFIG_TINY_RCU */ -void synchronize_rcu(void); void rcu_barrier(void); void synchronize_rcu_expedited(void); @@ -83,25 +58,6 @@ static inline void synchronize_rcu_bh_expedited(void) synchronize_sched(); } -struct notifier_block; - -#ifdef CONFIG_NO_HZ - -extern void rcu_enter_nohz(void); -extern void rcu_exit_nohz(void); - -#else /* #ifdef CONFIG_NO_HZ */ - -static inline void rcu_enter_nohz(void) -{ -} - -static inline void rcu_exit_nohz(void) -{ -} - -#endif /* #else #ifdef CONFIG_NO_HZ */ - #ifdef CONFIG_TINY_RCU static inline void rcu_preempt_note_context_switch(void) @@ -117,11 +73,6 @@ static inline int rcu_needs_cpu(int cpu) return 0; } -static inline int rcu_preempt_depth(void) -{ - return 0; -} - #else /* #ifdef CONFIG_TINY_RCU */ void rcu_preempt_note_context_switch(void); @@ -141,8 +92,6 @@ static inline void rcu_note_context_switch(int cpu) rcu_preempt_note_context_switch(); } -extern void rcu_check_callbacks(int cpu, int user); - /* * Return the number of grace periods. */ diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 54a20c11f98..95518e62879 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -30,59 +30,23 @@ #ifndef __LINUX_RCUTREE_H #define __LINUX_RCUTREE_H -struct notifier_block; - -extern void rcu_sched_qs(int cpu); -extern void rcu_bh_qs(int cpu); extern void rcu_note_context_switch(int cpu); extern int rcu_needs_cpu(int cpu); extern void rcu_cpu_stall_reset(void); #ifdef CONFIG_TREE_PREEMPT_RCU -extern void __rcu_read_lock(void); -extern void __rcu_read_unlock(void); -extern void synchronize_rcu(void); extern void exit_rcu(void); #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ -static inline void __rcu_read_lock(void) -{ - preempt_disable(); -} - -static inline void __rcu_read_unlock(void) -{ - preempt_enable(); -} - -#define synchronize_rcu synchronize_sched - static inline void exit_rcu(void) { } -static inline int rcu_preempt_depth(void) -{ - return 0; -} - #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ -static inline void __rcu_read_lock_bh(void) -{ - local_bh_disable(); -} -static inline void __rcu_read_unlock_bh(void) -{ - local_bh_enable(); -} - -extern void call_rcu_sched(struct rcu_head *head, - void (*func)(struct rcu_head *rcu)); extern void synchronize_rcu_bh(void); -extern void synchronize_sched(void); extern void synchronize_rcu_expedited(void); static inline void synchronize_rcu_bh_expedited(void) @@ -92,8 +56,6 @@ static inline void synchronize_rcu_bh_expedited(void) extern void rcu_barrier(void); -extern void rcu_check_callbacks(int cpu, int user); - extern long rcu_batches_completed(void); extern long rcu_batches_completed_bh(void); extern long rcu_batches_completed_sched(void); @@ -101,18 +63,6 @@ extern void rcu_force_quiescent_state(void); extern void rcu_bh_force_quiescent_state(void); extern void rcu_sched_force_quiescent_state(void); -#ifdef CONFIG_NO_HZ -void rcu_enter_nohz(void); -void rcu_exit_nohz(void); -#else /* CONFIG_NO_HZ */ -static inline void rcu_enter_nohz(void) -{ -} -static inline void rcu_exit_nohz(void) -{ -} -#endif /* CONFIG_NO_HZ */ - /* A context switch is a grace period for RCU-sched and RCU-bh. */ static inline int rcu_blocking_is_gp(void) { diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 561410f70d4..87f60f06b18 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -938,15 +938,6 @@ static void rcu_preempt_process_callbacks(void) { } -/* - * In classic RCU, call_rcu() is just call_rcu_sched(). - */ -void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu)) -{ - call_rcu_sched(head, func); -} -EXPORT_SYMBOL_GPL(call_rcu); - /* * Wait for an rcu-preempt grace period, but make it happen quickly. * But because preemptable RCU does not exist, map to rcu-sched. -- cgit v1.2.3-70-g09d2