Re: [PATCH v3] locking/rwsem: Add __always_inline annotation to __down_read_common() and inlined callers

[Peter Zijlstra <peterz@infradead.org>]

On Wed, May 03, 2023 at 02:33:51AM +0000, John Stultz wrote:
> 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 in traceevents will always be listed as
> __down_read_common().
> 
> So this patch adds __always_inline annotation to the common
> function (as well as the inlined helper callers) to force it to
> be inlined so the blocking function will be listed (via Wchan)
> in traceevents.
> 
> 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}*()")
> Reviewed-by: Waiman Long <longman@redhat.com>
> Reported-by: Tim Murray <timmurray@google.com>
> Signed-off-by: John Stultz <jstultz@google.com>

Thanks!