From d4efe6c5ad91f9a1f2f1d66b7fbfc87e320b2abc Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 28 Apr 2017 14:16:16 -0700 Subject: [PATCH] srcu: Shrink Tiny SRCU a bit In Tiny SRCU, __srcu_read_lock() is a trivial function, outweighed by its EXPORT_SYMBOL_GPL(), and on many architectures, its call sequence. This commit therefore moves it to srcutiny.h so that it can be inlined. Signed-off-by: Paul E. McKenney --- include/linux/srcutiny.h | 15 +++++++++++++++ kernel/rcu/srcutiny.c | 16 ---------------- 2 files changed, 15 insertions(+), 16 deletions(-) diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h index b8859179b001..b6edd9c8fdce 100644 --- a/include/linux/srcutiny.h +++ b/include/linux/srcutiny.h @@ -63,6 +63,21 @@ void srcu_drive_gp(struct work_struct *wp); void synchronize_srcu(struct srcu_struct *sp); +/* + * Counts the new reader in the appropriate per-CPU element of the + * srcu_struct. Can be invoked from irq/bh handlers, but the matching + * __srcu_read_unlock() must be in the same handler instance. Returns an + * index that must be passed to the matching srcu_read_unlock(). + */ +static inline int __srcu_read_lock(struct srcu_struct *sp) +{ + int idx; + + idx = READ_ONCE(sp->srcu_idx); + WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1); + return idx; +} + static inline void synchronize_srcu_expedited(struct srcu_struct *sp) { synchronize_srcu(sp); diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 32798eb14853..988543721d5d 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -95,22 +95,6 @@ void cleanup_srcu_struct(struct srcu_struct *sp) } EXPORT_SYMBOL_GPL(cleanup_srcu_struct); -/* - * Counts the new reader in the appropriate per-CPU element of the - * srcu_struct. Can be invoked from irq/bh handlers, but the matching - * __srcu_read_unlock() must be in the same handler instance. Returns an - * index that must be passed to the matching srcu_read_unlock(). - */ -int __srcu_read_lock(struct srcu_struct *sp) -{ - int idx; - - idx = READ_ONCE(sp->srcu_idx); - WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1); - return idx; -} -EXPORT_SYMBOL_GPL(__srcu_read_lock); - /* * Removes the count for the old reader from the appropriate element of * the srcu_struct. -- 2.20.1