From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: Yosry Ahmed <yosryahmed@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Seth Jennings <sjenning@redhat.com>,
Dan Streetman <ddstreet@ieee.org>,
Vitaly Wool <vitaly.wool@konsulko.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Nhat Pham <nphamcs@gmail.com>,
Domenico Cerasuolo <cerasuolodomenico@gmail.com>,
Yu Zhao <yuzhao@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [BUG mm-unstable] "kernel BUG at mm/swap.c:393!" on commit b9c91c43412f2e
Date: Wed, 21 Jun 2023 16:03:52 +0900 [thread overview]
Message-ID: <CAB=+i9TyX11=30yNiEq5UKfLJ9aBRuJEF6yQAQAnybhzkReLSg@mail.gmail.com> (raw)
In-Reply-To: <ZJKgThENoFlkJQmB@fedora>
On Wed, Jun 21, 2023 at 4:01 PM Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
>
> On Wed, Jun 07, 2023 at 07:51:43PM +0000, Yosry Ahmed wrote:
> > Commit 71024cb4a0bf ("frontswap: remove frontswap_tmem_exclusive_gets")
> > removed support for exclusive loads from frontswap as it was not used.
> > Bring back exclusive loads support to frontswap by adding an "exclusive"
> > output parameter to frontswap_ops->load.
> >
> > On the zswap side, add a module parameter to enable/disable exclusive
> > loads, and a config option to control the boot default value.
> > Refactor zswap entry invalidation in zswap_frontswap_invalidate_page()
> > into zswap_invalidate_entry() to reuse it in zswap_frontswap_load() if
> > exclusive loads are enabled.
> >
> > With exclusive loads, we avoid having two copies of the same page in
> > memory (compressed & uncompressed) after faulting it in from zswap. On
> > the other hand, if the page is to be reclaimed again without being
> > dirtied, it will be re-compressed. Compression is not usually slow, and
> > a page that was just faulted in is less likely to be reclaimed again
> > soon.
> >
> > Suggested-by: Yu Zhao <yuzhao@google.com>
> > Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
> > ---
> >
> > v1 -> v2:
> > - Add a module parameter to control whether exclusive loads are enabled
> > or not, the config option now controls the default boot value instead.
> > Replaced frontswap_ops->exclusive_loads by an output parameter to
> > frontswap_ops->load() (Johannes Weiner).
> > ---
>
> Hi Yosry, I was testing the latest mm-unstable and encountered a bug.
> It was bisectable and this is the first bad commit.
Oh, I forgot to mention how I was able to reproduce this:
$ stress-ng --bigheap 12
(my box have 24 cores)
>
> Attached config file and bisect log.
> The oops message is available at:
>
> https://social.kernel.org/media/eace06d71655b3cc76411366573e4a8ce240ad65b8fd20977d7c73eec9dc2253.jpg
>
> (the head commit is b9c91c43412f2e07 "mm: zswap: support exclusive loads")
> (it's an image because I tested it on real machine)
>
>
> This is what I have as swap space:
>
> $ cat /proc/swaps
> Filename Type Size Used Priority
> /var/swap file 134217724 0 -2
> /dev/zram0 partition 8388604 0 100
next prev parent reply other threads:[~2023-06-21 7:04 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-07 19:51 [PATCH v2 1/2] mm: zswap: support exclusive loads Yosry Ahmed
2023-06-07 20:44 ` Johannes Weiner
2023-06-21 7:01 ` [BUG mm-unstable] "kernel BUG at mm/swap.c:393!" on commit b9c91c43412f2e Hyeonggon Yoo
2023-06-21 7:03 ` Hyeonggon Yoo [this message]
2023-06-21 8:05 ` Yosry Ahmed
2023-06-21 9:06 ` Hyeonggon Yoo
2023-06-21 9:09 ` Yosry Ahmed
2023-06-21 9:18 ` Domenico Cerasuolo
2023-06-21 9:26 ` Yosry Ahmed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAB=+i9TyX11=30yNiEq5UKfLJ9aBRuJEF6yQAQAnybhzkReLSg@mail.gmail.com' \
--to=42.hyeyoo@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=cerasuolodomenico@gmail.com \
--cc=ddstreet@ieee.org \
--cc=hannes@cmpxchg.org \
--cc=konrad.wilk@oracle.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=nphamcs@gmail.com \
--cc=sjenning@redhat.com \
--cc=vitaly.wool@konsulko.com \
--cc=yosryahmed@google.com \
--cc=yuzhao@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.