diff options
| author | Waiman Long <longman@redhat.com> | 2022-03-22 11:20:57 -0400 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-04-05 10:24:34 +0200 |
| commit | f9e21aa9e6fb11355e54c8949a390d49ca21cde1 (patch) | |
| tree | 6e6139c7bf141b171e76a16fc9495d22d2573eeb /kernel/locking/rwsem.c | |
| parent | 8b023accc8df70e72f7704d29fead7ca914d6837 (diff) | |
locking/rwsem: No need to check for handoff bit if wait queue empty
Since commit d257cc8cb8d5 ("locking/rwsem: Make handoff bit handling
more consistent"), the handoff bit is always cleared if the wait queue
becomes empty. There is no need to check for RWSEM_FLAG_HANDOFF when
the wait list is known to be empty.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220322152059.2182333-2-longman@redhat.com
Diffstat (limited to 'kernel/locking/rwsem.c')
| -rw-r--r-- | kernel/locking/rwsem.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index acde5d6f1254..b077b1b2d4b3 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -977,12 +977,11 @@ queue: if (list_empty(&sem->wait_list)) { /* * In case the wait queue is empty and the lock isn't owned - * by a writer or has the handoff bit set, this reader can - * exit the slowpath and return immediately as its - * RWSEM_READER_BIAS has already been set in the count. + * by a writer, this reader can exit the slowpath and return + * immediately as its RWSEM_READER_BIAS has already been set + * in the count. */ - if (!(atomic_long_read(&sem->count) & - (RWSEM_WRITER_MASK | RWSEM_FLAG_HANDOFF))) { + if (!(atomic_long_read(&sem->count) & RWSEM_WRITER_MASK)) { /* Provide lock ACQUIRE */ smp_acquire__after_ctrl_dep(); raw_spin_unlock_irq(&sem->wait_lock); |