linux-kernel - Re: [RFC PATCH] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too

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Date:   Thu, 17 Feb 2022 14:45:24 +0000
From:   Aaron Tomlin <atomlin@...mlin.com>
To:     Frederic Weisbecker <frederic@...nel.org>
Cc:     Aaron Tomlin <atomlin@...hat.com>, Phil Auld <pauld@...hat.com>,
        tglx@...utronix.de, mingo@...nel.org, mingo@...hat.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [RFC PATCH] tick/sched: Ensure quiet_vmstat() is called when the
 idle tick was stopped too

On Thu 2022-02-17 13:57 +0100, Frederic Weisbecker wrote:
> Hmm, but does it matter? The issue seem to be that we can enter in idle loop without
> flushing vmstat. Or am I missing something else?
Frederic,

Yes, this is indeed the concern. So, the idea I had was to invoke
quiet_vmstat() regardless if the tick was stopped or not. If I understand
correctly, this should resolve the issue. Furthermore, folding of all
outstanding differentials will only occur when required. Thus performance
should be negligible.

Kind regards,

-- 
Aaron Tomlin