Re: 5.14-rc breaks iotop swap io monitoring.

[Dave Jones]

On Tue, Aug 24, 2021 at 10:31:16AM +0200, Peter Zijlstra wrote:
 > 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")

That does sound more relevant. however, even after echo 1  > /proc/sys/kernel/task_delayacct,
it still fails in the same way.

	Dave