From 95bf33b55ff4465399bad843f1d8d618c8baf1f3 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Apr 2019 14:07:24 +0200 Subject: rcu/sync: Kill rcu_sync_type/gp_type Now that the RCU flavors have been consolidated, rcu_sync_type makes no sense because none of internal update functions aside from .held() depend on gp_type. This commit therefore removes this field and consolidates the relevant code. Signed-off-by: Oleg Nesterov [ paulmck: Added RCU and RCU-bh checks to rcu_sync_is_idle(). ] [ paulmck: And applied subsequent feedback from Oleg Nesterov. ] Signed-off-by: Paul E. McKenney --- include/linux/percpu-rwsem.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/percpu-rwsem.h') diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 03cb4b6f842e..6887636ea169 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -20,7 +20,7 @@ struct percpu_rw_semaphore { #define DEFINE_STATIC_PERCPU_RWSEM(name) \ static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name); \ static struct percpu_rw_semaphore name = { \ - .rss = __RCU_SYNC_INITIALIZER(name.rss, RCU_SCHED_SYNC), \ + .rss = __RCU_SYNC_INITIALIZER(name.rss), \ .read_count = &__percpu_rwsem_rc_##name, \ .rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \ .writer = __RCUWAIT_INITIALIZER(name.writer), \ -- cgit v1.2.3 From 3f2947b78151ec938dc06aea4ba0e11e56becdff Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 23 Apr 2019 18:32:41 +0200 Subject: locking/percpu-rwsem: Add DEFINE_PERCPU_RWSEM(), use it to initialize cgroup_threadgroup_rwsem Turn DEFINE_STATIC_PERCPU_RWSEM() into __DEFINE_PERCPU_RWSEM() with the additional "is_static" argument to introduce DEFINE_PERCPU_RWSEM(). Change cgroup.c to use DEFINE_PERCPU_RWSEM(cgroup_threadgroup_rwsem). Signed-off-by: Oleg Nesterov Reviewed-by: Ingo Molnar Signed-off-by: Paul E. McKenney --- include/linux/percpu-rwsem.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'include/linux/percpu-rwsem.h') diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 6887636ea169..2809b44cbbee 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -17,14 +17,18 @@ struct percpu_rw_semaphore { int readers_block; }; -#define DEFINE_STATIC_PERCPU_RWSEM(name) \ +#define __DEFINE_PERCPU_RWSEM(name, is_static) \ static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name); \ -static struct percpu_rw_semaphore name = { \ +is_static struct percpu_rw_semaphore name = { \ .rss = __RCU_SYNC_INITIALIZER(name.rss), \ .read_count = &__percpu_rwsem_rc_##name, \ .rw_sem = __RWSEM_INITIALIZER(name.rw_sem), \ .writer = __RCUWAIT_INITIALIZER(name.writer), \ } +#define DEFINE_PERCPU_RWSEM(name) \ + __DEFINE_PERCPU_RWSEM(name, /* not static */) +#define DEFINE_STATIC_PERCPU_RWSEM(name) \ + __DEFINE_PERCPU_RWSEM(name, static) extern int __percpu_down_read(struct percpu_rw_semaphore *, int); extern void __percpu_up_read(struct percpu_rw_semaphore *); -- cgit v1.2.3 From 94a9717b3c40e77a54e4afacd8f19a9a86bfeead Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Mon, 20 May 2019 16:59:12 -0400 Subject: locking/rwsem: Make rwsem->owner an atomic_long_t The rwsem->owner contains not just the task structure pointer, it also holds some flags for storing the current state of the rwsem. Some of the flags may have to be atomically updated. To reflect the new reality, the owner is now changed to an atomic_long_t type. New helper functions are added to properly separate out the task structure pointer and the embedded flags. Suggested-by: Peter Zijlstra Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Cc: Borislav Petkov Cc: Davidlohr Bueso Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Tim Chen Cc: Will Deacon Cc: huang ying Link: https://lkml.kernel.org/r/20190520205918.22251-14-longman@redhat.com Signed-off-by: Ingo Molnar --- include/linux/percpu-rwsem.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/percpu-rwsem.h') diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 03cb4b6f842e..0a43830f1932 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -117,7 +117,7 @@ static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem, lock_release(&sem->rw_sem.dep_map, 1, ip); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER if (!read) - sem->rw_sem.owner = RWSEM_OWNER_UNKNOWN; + atomic_long_set(&sem->rw_sem.owner, RWSEM_OWNER_UNKNOWN); #endif } @@ -127,7 +127,7 @@ static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem, lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip); #ifdef CONFIG_RWSEM_SPIN_ON_OWNER if (!read) - sem->rw_sem.owner = current; + atomic_long_set(&sem->rw_sem.owner, (long)current); #endif } -- cgit v1.2.3