From: Minchan Kim <minchan@kernel.org>
To: Shakeel Butt <shakeelb@google.com>
Cc: Heiko Carstens <hca@linux.ibm.com>,
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: Thu, 18 Mar 2021 08:19:12 -0700 [thread overview]
Message-ID: <YFNvcEDfMUmDi/Fp@google.com> (raw)
In-Reply-To: <CALvZod7ggc=98wJauDmB=05+9MnLo0_ppeTHfZrxj5idNsD1iA@mail.gmail.com>
On Wed, Mar 17, 2021 at 06:49:27PM -0700, Shakeel Butt wrote:
> On Wed, Mar 17, 2021 at 6:31 PM Minchan Kim <minchan@kernel.org> wrote:
> >
> [...]
> > >
> > > The simplest solution I can think of is to do set_page_private(page,
> > > entry.val) before swap_readpage(page, true) and set_page_private(page,
> > > 0) after.
> >
> > Since I did't read the bug in detail, I couldn't come up with how the
> > missing reset is connected the problem while missing set_page_private
> > with entry.val is clear.
>
> This particular bug is about missing set_page_private(page,
> entry.val). I was wondering if we should always reset page->private or
> just leave it as is? I think it is safer to reset.
For safeness point of view, I couldn't find something wrong since
page_private will be used once the page turns out PageSwapCache.
(please chime in if someone found)
Having said, I agree it would be more consistent and safer.
prev parent reply other threads:[~2021-03-18 15:20 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
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 [this message]
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