From b3e627d3d5092a87fc9b9e37e341610cfecfbfdc Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Tue, 15 Oct 2019 02:55:57 +0000 Subject: rcu: Make PREEMPT_RCU be a modifier to TREE_RCU Currently PREEMPT_RCU and TREE_RCU are mutually exclusive Kconfig options. But PREEMPT_RCU actually specifies a kind of TREE_RCU, namely a preemptible TREE_RCU. This commit therefore makes PREEMPT_RCU be a modifer to the TREE_RCU Kconfig option. This has the benefit of simplifying several of the #if expressions that formerly needed to check both, but now need only check one or the other. Signed-off-by: Lai Jiangshan Signed-off-by: Lai Jiangshan Reviewed-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 0b7506330c87..70a41cd8f58d 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -167,7 +167,7 @@ do { \ * TREE_RCU and rcu_barrier_() primitives in TINY_RCU. */ -#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) +#if defined(CONFIG_TREE_RCU) #include #elif defined(CONFIG_TINY_RCU) #include @@ -601,7 +601,7 @@ do { \ * read-side critical section that would block in a !PREEMPT kernel. * But if you want the full story, read on! * - * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU), + * In non-preemptible RCU implementations (pure TREE_RCU and TINY_RCU), * it is illegal to block while in an RCU read-side critical section. * In preemptible RCU implementations (PREEMPT_RCU) in CONFIG_PREEMPTION * kernel builds, RCU read-side critical sections may be preempted, -- cgit From 90326f0521a88004194f88f1b597b54347482b5c Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 15 Oct 2019 21:18:14 +0200 Subject: rcu: Use CONFIG_PREEMPTION where appropriate The config option `CONFIG_PREEMPT' is used for the preemption model "Low-Latency Desktop". The config option `CONFIG_PREEMPTION' is enabled when kernel preemption is enabled which is true for the preemption model `CONFIG_PREEMPT' and `CONFIG_PREEMPT_RT'. Use `CONFIG_PREEMPTION' if it applies to both preemption models and not just to `CONFIG_PREEMPT'. Cc: "Paul E. McKenney" Cc: Josh Triplett Cc: Steven Rostedt Cc: Mathieu Desnoyers Cc: Lai Jiangshan Cc: Joel Fernandes Cc: Davidlohr Bueso Cc: rcu@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 70a41cd8f58d..eb32fff81c30 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -154,7 +154,7 @@ static inline void exit_tasks_rcu_finish(void) { } * * This macro resembles cond_resched(), except that it is defined to * report potential quiescent states to RCU-tasks even if the cond_resched() - * machinery were to be shut off, as some advocate for PREEMPT kernels. + * machinery were to be shut off, as some advocate for PREEMPTION kernels. */ #define cond_resched_tasks_rcu_qs() \ do { \ @@ -598,7 +598,7 @@ do { \ * * You can avoid reading and understanding the next paragraph by * following this rule: don't put anything in an rcu_read_lock() RCU - * read-side critical section that would block in a !PREEMPT kernel. + * read-side critical section that would block in a !PREEMPTION kernel. * But if you want the full story, read on! * * In non-preemptible RCU implementations (pure TREE_RCU and TINY_RCU), -- cgit From 4414abf89158d734a83c99f6504f648417bd9550 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 23 Sep 2019 16:31:42 -0700 Subject: rcu: Remove rcu_swap_protected() Now that the calls to rcu_swap_protected() have been replaced by rcu_replace_pointer(), this commit removes rcu_swap_protected(). Link: https://lore.kernel.org/lkml/CAHk-=wiAsJLw1egFEE=Z7-GGtM6wcvtyytXZA1+BHqta4gg6Hw@mail.gmail.com/ Reported-by: Linus Torvalds Signed-off-by: Paul E. McKenney Cc: Bart Van Assche Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Johannes Thumshirn Cc: Shane M Seymour Cc: Martin K. Petersen --- include/linux/rcupdate.h | 16 ---------------- 1 file changed, 16 deletions(-) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 0b7506330c87..fe470243acdd 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -400,22 +400,6 @@ do { \ __tmp; \ }) -/** - * rcu_swap_protected() - swap an RCU and a regular pointer - * @rcu_ptr: RCU pointer - * @ptr: regular pointer - * @c: the conditions under which the dereference will take place - * - * Perform swap(@rcu_ptr, @ptr) where @rcu_ptr is an RCU-annotated pointer and - * @c is the argument that is passed to the rcu_dereference_protected() call - * used to read that pointer. - */ -#define rcu_swap_protected(rcu_ptr, ptr, c) do { \ - typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c)); \ - rcu_assign_pointer((rcu_ptr), (ptr)); \ - (ptr) = __tmp; \ -} while (0) - /** * rcu_access_pointer() - fetch RCU pointer with no dereferencing * @p: The pointer to read -- cgit From e1350e8e0ea5d959c23c5e593ff3026a67dbb049 Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Tue, 15 Oct 2019 14:48:22 +0100 Subject: rcu: Move rcu_{expedited,normal} definitions into rcupdate.h This commit moves the rcu_{expedited,normal} definitions from kernel/rcu/update.c to include/linux/rcupdate.h to make sure they are in sync, and also to avoid the following warning from sparse: kernel/ksysfs.c:150:5: warning: symbol 'rcu_expedited' was not declared. Should it be static? kernel/ksysfs.c:167:5: warning: symbol 'rcu_normal' was not declared. Should it be static? Signed-off-by: Ben Dooks Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/rcupdate.h') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index fe470243acdd..bb36379606d0 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -896,4 +896,8 @@ rcu_head_after_call_rcu(struct rcu_head *rhp, rcu_callback_t f) return false; } +/* kernel/ksysfs.c definitions */ +extern int rcu_expedited; +extern int rcu_normal; + #endif /* __LINUX_RCUPDATE_H */ -- cgit