Re: 5.14-rc breaks iotop swap io monitoring.

From: Linus Torvalds
Date: Tue Aug 24 2021 - 12:34:26 EST


On Tue, Aug 24, 2021 at 8:19 AM Dave Jones <davej@xxxxxxxxxxxxxxxxx> wrote:
>
> On Tue, Aug 24, 2021 at 10:31:16AM +0200, Peter Zijlstra wrote:
> >
> > If you need DELAYACCT I'm thinking:
> >
> > e4042ad49235 ("delayacct: Default disabled")
> >
> > and
> >
> > 0cd7c741f01d ("delayacct: Add sysctl to enable at runtime")
>
> That does sound more relevant. however, even after echo 1 > /proc/sys/kernel/task_delayacct,
> it still fails in the same way.

Hmm.

What happens if you boot with the 'delayacct' kernel parameter.

Even if you enable it at run-time, processes that have been started
before it was enabled won't actually have the 'tsk->delays'
allocation. So I'm not sure how effective the run-time thing is.

Linus