Re: 5.14-rc breaks iotop swap io monitoring.

[Peter Zijlstra]

On Mon, Aug 23, 2021 at 11:16:48PM -0400, Dave Jones wrote:
> I just noticed that in 5.14-rc running iotop, it complains on startup
> that "CONFIG_TASK_DELAY_ACCT not enabled in kernel, cannot determine
> SWAPIN and IO %" and sure enough a bunch of columns show up as
> 'unavailable'.
> 
> My suspicion is this commit, which I've not confirmed yet as it doesn't
> cleanly revert.  I'll poke at it some more in the morning, but figured
> I'd bring it up sans-evidence in the hope that I'll wake up to someone
> having an Ah-ha moment.

If you need DELAYACCT I'm thinking:

  e4042ad49235 ("delayacct: Default disabled")

and

  0cd7c741f01d ("delayacct: Add sysctl to enable at runtime")

might be more relevant..