linux-kernel - Re: [PATCH 3/6] sched: Extract __schedule

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Message-ID: <20230816124848.GA641857@lorien.usersys.redhat.com>
Date:   Wed, 16 Aug 2023 08:48:48 -0400
From:   Phil Auld <pauld@...hat.com>
To:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:     Peter Zijlstra <peterz@...radead.org>, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, bsegall@...gle.com,
        boqun.feng@...il.com, swood@...hat.com, bristot@...hat.com,
        dietmar.eggemann@....com, mingo@...hat.com, jstultz@...gle.com,
        juri.lelli@...hat.com, mgorman@...e.de, rostedt@...dmis.org,
        vschneid@...hat.com, vincent.guittot@...aro.org,
        longman@...hat.com, will@...nel.org
Subject: Re: [PATCH 3/6] sched: Extract __schedule_loop()

On Wed, Aug 16, 2023 at 02:20:07PM +0200 Sebastian Andrzej Siewior wrote:
> On 2023-08-16 07:39:45 [-0400], Phil Auld wrote:
> > I do.  Admittedly I'm not an expert in how the wchan unwinding works but
> > we have a slightly older version of this patch in our kernel (schedule_loop
> > not __schedule_loop). When I added __sched it fixed it.   Maybe there
> > is something else but that seemed pretty obvious. 
> > 
> > 
> > /* Attach to any functions which should be ignored in wchan output. */
> > #define __sched		__section(".sched.text")
> > 
> > I can't explain why you are not seeing it.
> 
> as peterz pointed out, it is marked __always_inline so the compiler
> shouldn't make a separate function out of it.
> Could you check with _this_ series? The schedule_loop variant is in RT
> and does not have this inline thingy. So it would be good if the issue
> you report actually exists in the series that has been posted.
>

Hhm, yes.  I was looking at the issue in our tree when these patches
came by. Sorry... I seem to have glossed over the __always_inline.
That would certainly work as well and, of course, does explain why you
aren't seeing it.

read more. talk less :)


Cheers,
Phil

> > Cheers,
> > Phil
> 
> Sebastian
> 

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