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Date:   Mon, 17 Apr 2023 13:19:49 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     John Stultz <jstultz@google.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Minchan Kim <minchan@kernel.org>,
        Tim Murray <timmurray@google.com>,
        Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>, kernel-team@android.com,
        stable@vger.kernel.org
Subject: Re: [PATCH v2] locking/rwsem: Add __always_inline annotation to
 __down_read_common()
Message-ID: <20230417111949.GJ83892@hirez.programming.kicks-ass.net>
References: <20230412023839.2869114-1-jstultz@google.com>
 <20230412035905.3184199-1-jstultz@google.com>
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On Wed, Apr 12, 2023 at 03:59:05AM +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 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.

I'm a wee bit confused; what are you looking at? Wchan? What is stopping
the compiler from now handing you
__down_read{,_interruptible,_killable}() instead? Is that fine?