Re: khugepaged eating 100%CPU

From: Michal Hocko
Date: Mon Feb 07 2011 - 16:16:09 EST


On Mon 07-02-11 22:06:54, Michal Hocko wrote:
> Hi Andrea,
>
> I am currently running into an issue when khugepaged is running 100% on
> one of my CPUs for a long time (at least one hour as I am writing the
> email). The kernel is the clean 2.6.38-rc3 (i386) vanilla kernel.
>
> I have tried to disable defrag but it didn't help (I haven't rebooted
> after setting the value). I am not sure what information is helpful and
> also not sure whether I am able to reproduce it after restart (it is the
> first time I can see this problem) so sorry for the poor report.
>
> Here is some basic info which might be useful (config and sysrq+t are
> attached):
> =========

And I have just realized that I forgot about the daemon stack:
# cat /proc/573/stack
[<c019c981>] shrink_zone+0x1b9/0x455
[<c019d462>] do_try_to_free_pages+0x9d/0x301
[<c019d803>] try_to_free_pages+0xb3/0x104
[<c01966d7>] __alloc_pages_nodemask+0x358/0x589
[<c01bf314>] khugepaged+0x13f/0xc60
[<c014c301>] kthread+0x67/0x6c
[<c0102db6>] kernel_thread_helper+0x6/0x10
[<ffffffff>] 0xffffffff
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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