From 293e2421fe25839500207eda123cc4475f8d17b8 Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Wed, 23 Mar 2016 23:11:48 +0800 Subject: rcu: Remove superfluous versions of rcu_read_lock_sched_held() Currently, we have four versions of rcu_read_lock_sched_held(), depending on the combined choices on PREEMPT_COUNT and DEBUG_LOCK_ALLOC. However, there is an existing function preemptible() that already distinguishes between the PREEMPT_COUNT=y and PREEMPT_COUNT=n cases, and allows these four implementations to be consolidated down to two. This commit therefore uses preemptible() to achieve this consolidation. Note that there could be a small performance regression in the case of CONFIG_DEBUG_LOCK_ALLOC=y && PREEMPT_COUNT=n. However, given the overhead associated with CONFIG_DEBUG_LOCK_ALLOC=y, this should be down in the noise. Signed-off-by: Boqun Feng Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) (limited to 'include/linux') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 45de591657a6..5f1533e3d032 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -508,14 +508,7 @@ int rcu_read_lock_bh_held(void); * CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU-sched read-side * critical section unless it can prove otherwise. */ -#ifdef CONFIG_PREEMPT_COUNT int rcu_read_lock_sched_held(void); -#else /* #ifdef CONFIG_PREEMPT_COUNT */ -static inline int rcu_read_lock_sched_held(void) -{ - return 1; -} -#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */ #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ @@ -532,18 +525,10 @@ static inline int rcu_read_lock_bh_held(void) return 1; } -#ifdef CONFIG_PREEMPT_COUNT static inline int rcu_read_lock_sched_held(void) { - return preempt_count() != 0 || irqs_disabled(); + return !preemptible(); } -#else /* #ifdef CONFIG_PREEMPT_COUNT */ -static inline int rcu_read_lock_sched_held(void) -{ - return 1; -} -#endif /* #else #ifdef CONFIG_PREEMPT_COUNT */ - #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ #ifdef CONFIG_PROVE_RCU -- cgit v1.2.3-71-gd317 From 291783b8ad77a83a6fdf91d55eee7f1ad72ed4d1 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 12 Jan 2016 13:43:30 -0800 Subject: rcutorture: Expedited-GP batch progress access to torturing This commit provides rcu_exp_batches_completed() and rcu_exp_batches_completed_sched() functions to allow torture-test modules to check how many expedited grace period batches have completed. These are analogous to the existing rcu_batches_completed(), rcu_batches_completed_bh(), and rcu_batches_completed_sched() functions. Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 16 ++++++++++++++++ include/linux/rcutree.h | 2 ++ kernel/rcu/tree.c | 22 ++++++++++++++++++++++ 3 files changed, 40 insertions(+) (limited to 'include/linux') diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 64809aea661c..93aea75029fb 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -149,6 +149,22 @@ static inline unsigned long rcu_batches_completed_sched(void) return 0; } +/* + * Return the number of expedited grace periods completed. + */ +static inline unsigned long rcu_exp_batches_completed(void) +{ + return 0; +} + +/* + * Return the number of expedited sched grace periods completed. + */ +static inline unsigned long rcu_exp_batches_completed_sched(void) +{ + return 0; +} + static inline void rcu_force_quiescent_state(void) { } diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index ad1eda9fa4da..5043cb823fb2 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -87,6 +87,8 @@ unsigned long rcu_batches_started_sched(void); unsigned long rcu_batches_completed(void); unsigned long rcu_batches_completed_bh(void); unsigned long rcu_batches_completed_sched(void); +unsigned long rcu_exp_batches_completed(void); +unsigned long rcu_exp_batches_completed_sched(void); void show_rcu_gp_kthreads(void); void rcu_force_quiescent_state(void); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 531a328076bd..88df64087dfe 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -459,6 +459,28 @@ unsigned long rcu_batches_completed_bh(void) } EXPORT_SYMBOL_GPL(rcu_batches_completed_bh); +/* + * Return the number of RCU expedited batches completed thus far for + * debug & stats. Odd numbers mean that a batch is in progress, even + * numbers mean idle. The value returned will thus be roughly double + * the cumulative batches since boot. + */ +unsigned long rcu_exp_batches_completed(void) +{ + return rcu_state_p->expedited_sequence; +} +EXPORT_SYMBOL_GPL(rcu_exp_batches_completed); + +/* + * Return the number of RCU-sched expedited batches completed thus far + * for debug & stats. Similar to rcu_exp_batches_completed(). + */ +unsigned long rcu_exp_batches_completed_sched(void) +{ + return rcu_sched_state.expedited_sequence; +} +EXPORT_SYMBOL_GPL(rcu_exp_batches_completed_sched); + /* * Force a quiescent state. */ -- cgit v1.2.3-71-gd317