Apparently despite it being marked inline, the compiler may not inline __down_read_common() which makes it difficult to identify the cause of lock contention, as the blocked function will always be listed as __down_read_common().
So this patch adds __always_inline annotation to the function to force it to be inlines so the calling function will be listed.
Cc: Minchan Kim minchan@kernel.org Cc: Tim Murray timmurray@google.com Cc: Peter Zijlstra peterz@infradead.org Cc: Ingo Molnar mingo@redhat.com Cc: Will Deacon will@kernel.org Cc: Waiman Long longman@redhat.com Cc: Boqun Feng boqun.feng@gmail.com Cc: kernel-team@android.com Cc: stable@vger.kernel.org Fixes: c995e638ccbb ("locking/rwsem: Fold __down_{read,write}*()") Reported-by: Tim Murray timmurray@google.com Signed-off-by: John Stultz jstultz@google.com --- v2: Reworked to use __always_inline instead of __sched as suggested by Waiman Long --- kernel/locking/rwsem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index acb5a50309a1..e99eef8ea552 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -1240,7 +1240,7 @@ static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem) /* * lock for reading */ -static inline int __down_read_common(struct rw_semaphore *sem, int state) +static __always_inline int __down_read_common(struct rw_semaphore *sem, int state) { int ret = 0; long count;