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| author | Waiman Long <longman@redhat.com> | 2024-02-22 10:05:39 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2024-02-28 13:08:38 +0100 |
| commit | d566c78659eccf085f905fd266fc461de92eaa8f (patch) | |
| tree | ac40feae9dc18fb670fdb4ee805d2202e8642789 /kernel/locking | |
| parent | d6cac0b6b0115fd0a5f51a49401473626e4e4fe7 (diff) | |
| download | linux-d566c78659eccf085f905fd266fc461de92eaa8f.tar.gz linux-d566c78659eccf085f905fd266fc461de92eaa8f.tar.bz2 linux-d566c78659eccf085f905fd266fc461de92eaa8f.zip | |
locking/rwsem: Clarify that RWSEM_READER_OWNED is just a hint
Clarify in the comments that the RWSEM_READER_OWNED bit in the owner
field is just a hint, not an authoritative state of the rwsem.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20240222150540.79981-4-longman@redhat.com
Diffstat (limited to 'kernel/locking')
| -rw-r--r-- | kernel/locking/rwsem.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 2340b6d90ec6..c6d17aee4209 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -35,7 +35,7 @@ /* * The least significant 2 bits of the owner value has the following * meanings when set. - * - Bit 0: RWSEM_READER_OWNED - The rwsem is owned by readers + * - Bit 0: RWSEM_READER_OWNED - rwsem may be owned by readers (just a hint) * - Bit 1: RWSEM_NONSPINNABLE - Cannot spin on a reader-owned lock * * When the rwsem is reader-owned and a spinning writer has timed out, @@ -1002,8 +1002,8 @@ rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, unsigned int stat /* * To prevent a constant stream of readers from starving a sleeping - * waiter, don't attempt optimistic lock stealing if the lock is - * currently owned by readers. + * writer, don't attempt optimistic lock stealing if the lock is + * very likely owned by readers. */ if ((atomic_long_read(&sem->owner) & RWSEM_READER_OWNED) && (rcnt > 1) && !(count & RWSEM_WRITER_LOCKED)) |