Re: SLUB: purpose of sysfs events on cache creation/removal

From: Michal Koutný
Date: Mon Jan 27 2020 - 12:33:42 EST


On Sat, Jan 18, 2020 at 04:15:28PM -0800, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > situations, the udev events seem to cause useless tickling of udevd.
> > [...]
> > and I drew the following ballpark conclusion:
> > 1.7% CPU time at 1 event/s -> 60 event/s 100% cpu
> Thanks. What effect does this patch have upon these numbers?
When I rerun the script with patched kernel, udev sit mostly idle (there
were no other udev event sources). So the number can be said to drop to
0% CPU time / event/s.

> Typically the author, but not always. If someone else is particularly
> motivated to get a patch merged up they can take it over.
Christopher, do you consider resending your patch? (I second that it
exposes the internal details (wrt cgroup caches) and I can observe the
just reading the events by udevd wastes CPU time.)


Thanks,
Michal

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