From: Andrew Morton <akpm@linux-foundation.org>
To: Hungyu Lin <dennylin0707@gmail.com>
Cc: bsingharora@gmail.com, yang.yang29@zte.com.cn,
wang.yaxin@zte.com.cn, wang.yong12@zte.com.cn, xu.xin@linux.dev,
jiang.kun2@zte.com.cn, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] delayacct: Preserve delay extrema when aggregating taskstats
Date: Wed, 21 Oct 2026 16:15:06 -0700 [thread overview]
Message-ID: <20261021161506.7baa42839def1312e177243c@linux-foundation.org> (raw)
In-Reply-To: <20261021010022.85881-1-dennylin0707@gmail.com>
On Wed, 21 Oct 2026 01:00:22 +0000 Hungyu Lin <dennylin0707@gmail.com> wrote:
> delayacct_add_tsk() adds each task's statistics to the accumulated TGID
> statistics, but overwrites the delay maxima, minima and peak timestamps.
> Consequently, the last task determines these fields, and a task with no
> recorded delay can erase an earlier task's peak despite a nonzero total.
>
> Keep the largest maximum and its associated timestamp, and combine the
> minima with min_not_zero() since zero denotes an unrecorded delay. Apply
> this to CPU delay and the seven delay types handled by UPDATE_DELAY().
> Single-task queries still start with zeroed statistics and retain the
> task's values.
Looks good, thanks.
To improve understandability it would be useful to include a getdelays
-d -t before/after example in the changelog.
prev parent reply other threads:[~2026-10-21 23:15 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-21 1:00 Hungyu Lin
2026-10-21 14:54 ` Bradley Morgan
2026-10-21 23:15 ` Andrew Morton [this message]
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