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| author |   Peter Zijlstra <peterz@infradead.org> | 2019-10-30 20:17:51 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2020-02-11 13:10:54 +0100 |
| commit | 71365d40232110f7b029befc9033ea311d680611 (patch) | |
| tree | da9cf44abea7c38e244c2b2dd7e6ef587c4146dc /include/linux/percpu-rwsem.h | |
| parent | locking/percpu-rwsem: Convert to bool (diff) | |
| download | linux-dev-71365d40232110f7b029befc9033ea311d680611.tar.xz linux-dev-71365d40232110f7b029befc9033ea311d680611.zip | |
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
Diffstat (limited to 'include/linux/percpu-rwsem.h')
| -rw-r--r-- | include/linux/percpu-rwsem.h | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h index 4ceaa1921951..bb5b71c1e446 100644 --- a/include/linux/percpu-rwsem.h +++ b/include/linux/percpu-rwsem.h @@ -59,8 +59,9 @@ static inline void percpu_down_read(struct percpu_rw_semaphore *sem) * and that once the synchronize_rcu() is done, the writer will see * anything we did within this RCU-sched read-size critical section. */ - __this_cpu_inc(*sem->read_count); - if (unlikely(!rcu_sync_is_idle(&sem->rss))) + if (likely(rcu_sync_is_idle(&sem->rss))) + __this_cpu_inc(*sem->read_count); + else __percpu_down_read(sem, false); /* Unconditional memory barrier */ /* * The preempt_enable() prevents the compiler from @@ -77,8 +78,9 @@ static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem) /* * Same as in percpu_down_read(). */ - __this_cpu_inc(*sem->read_count); - if (unlikely(!rcu_sync_is_idle(&sem->rss))) + if (likely(rcu_sync_is_idle(&sem->rss))) + __this_cpu_inc(*sem->read_count); + else ret = __percpu_down_read(sem, true); /* Unconditional memory barrier */ preempt_enable(); /* |