Re: 5.14-rc breaks iotop swap io monitoring.

[Linus Torvalds]

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