locking/percpu-rwsem: Move __this_cpu_inc() into the slowpath

As preparation to rework __percpu_down_read() move the
__this_cpu_inc() into it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lkml.kernel.org/r/20200131151540.041600199@infradead.org
This commit is contained in:
Peter Zijlstra
2019-10-30 20:17:51 +01:00
committed by Ingo Molnar
parent 206c98ffbe
commit 71365d4023
2 changed files with 8 additions and 4 deletions

View File

@@ -47,6 +47,8 @@ EXPORT_SYMBOL_GPL(percpu_free_rwsem);
bool __percpu_down_read(struct percpu_rw_semaphore *sem, bool try)
{
__this_cpu_inc(*sem->read_count);
/*
* Due to having preemption disabled the decrement happens on
* the same CPU as the increment, avoiding the