From: Heiko Carstens <hca@linux.ibm.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Roman Gushchin <guro@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Hugh Dickins <hughd@google.com>,
Juergen Christ <jchrist@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>, Linux MM <linux-mm@kvack.org>,
Linux-Next Mailing List <linux-next@vger.kernel.org>
Subject: Re: [BUG -next] "memcg: charge before adding to swapcache on swapin" broken
Date: Wed, 17 Mar 2021 22:11:02 +0100 [thread overview]
Message-ID: <YFJwZoUalBM/lBBr@osiris> (raw)
In-Reply-To: <YFJqJeMDc/JCjfSv@osiris>
On Wed, Mar 17, 2021 at 09:44:21PM +0100, Heiko Carstens wrote:
> On Wed, Mar 17, 2021 at 08:44:14AM -0700, Shakeel Butt wrote:
> > > Config below. And the fun thing is that I cannot reproduce it today
> > > anymore with the elfutils test case - what _seems_ to be different is
> > > that the test suite runs much faster than yesterday evening. Usually
> > > an indication that there is no steal time (other guests which steal
> > > cpu time), which again _could_ indicate a race / lack of locking
> > > somewhere.
> > > This is kind of odd, since yesterday evening it was very reliable to
> > > trigger the bug :/
> > >
> >
> > Thanks for the config. One question regarding swap, is it disk based
> > swap or zram?
>
> Swap device is a real disk.
>
> > By guests, do you mean there was another significant workload running
> > on the machine in parallel to the tests?
>
> That I don't know. I didn't check. I still can't reproduce with
> elfutils anymore, however...
>
> > If you don't mind can you try swapping01 as well.
>
> ltp's swapping01 test triggers immediately random processes being
> killed with SIGSEGV. I also tested with linux-next 20210316 and _only_
> "memcg: charge before adding to swapcache on swapin" being reverted on
> top, and the problem is away - so it looks like the result of
> yesterday's bisect is indeed valid.
I have to correct myself, actually the system has both: a real disk
_and_ zram as swap devices:
# swapon -s
Filename Type Size Used Priority
/dev/dasdb1 partition 21635084 0 -2
/dev/zram0 partition 1014780 0 100
When I disable /dev/zram with "swapoff /dev/zram0" the problem is away
as well, even with your patch applied.
next prev parent reply other threads:[~2021-03-17 21:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 21:08 [BUG -next] "memcg: charge before adding to swapcache on swapin" broken Heiko Carstens
2021-03-16 21:21 ` Shakeel Butt
2021-03-17 0:46 ` Heiko Carstens
2021-03-17 8:36 ` Christian Borntraeger
2021-03-17 13:33 ` Shakeel Butt
2021-03-17 15:26 ` Heiko Carstens
2021-03-17 15:44 ` Shakeel Butt
2021-03-17 20:44 ` Heiko Carstens
2021-03-17 21:11 ` Heiko Carstens [this message]
2021-03-17 21:39 ` Shakeel Butt
2021-03-18 0:23 ` Shakeel Butt
2021-03-18 1:30 ` Minchan Kim
2021-03-18 1:49 ` Shakeel Butt
2021-03-18 15:19 ` Minchan Kim
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