From: Peter Xu <peterx@redhat.com>
To: David Stevens <stevensd@chromium.org>
Cc: linux-mm@kvack.org, Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Yang Shi <shy828301@gmail.com>,
David Hildenbrand <david@redhat.com>,
Hugh Dickins <hughd@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 3/3] mm/khugepaged: maintain page cache uptodate flag
Date: Tue, 21 Feb 2023 17:18:22 -0500 [thread overview]
Message-ID: <Y/VDLvLpiHkRgVjs@x1n> (raw)
In-Reply-To: <20230217085439.2826375-4-stevensd@google.com>
On Fri, Feb 17, 2023 at 05:54:39PM +0900, David Stevens wrote:
> From: David Stevens <stevensd@chromium.org>
>
> Make sure that collapse_file doesn't interfere with checking the
> uptodate flag in the page cache by only inserting hpage into the page
> cache after it has been updated and marked uptodate. This is achieved by
> simply not replacing present pages with hpage when iterating over them
> target range. The present pages are already locked, so replacing the
> with the locked hpage before the collapse is finalized is unnecessary.
>
> This fixes a race where folio_seek_hole_data would mistake hpage for
> an fallocated but unwritten page. This race is visible to userspace via
> data temporarily disappearing from SEEK_DATA/SEEK_HOLE.
>
> Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages")
> Signed-off-by: David Stevens <stevensd@chromium.org>
Per my knowledge, this one looks all correct too.
Acked-by: Peter Xu <peterx@redhat.com>
So at least to me the whole set looks mostly good except patch 1 needs some
confirmation.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2023-02-21 22:18 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-17 8:54 [PATCH v4 0/3] mm/khugepaged: fix khugepaged+shmem races David Stevens
2023-02-17 8:54 ` [PATCH v4 1/3] mm/khugepaged: refactor collapse_file control flow David Stevens
2023-02-17 23:44 ` Yang Shi
2023-02-21 21:54 ` Peter Xu
2023-02-21 22:28 ` Yang Shi
2023-02-22 4:08 ` David Stevens
2023-02-22 16:24 ` Peter Xu
2023-02-17 8:54 ` [PATCH v4 2/3] mm/khugepaged: skip shmem with userfaultfd David Stevens
2023-02-21 22:12 ` Peter Xu
2023-02-17 8:54 ` [PATCH v4 3/3] mm/khugepaged: maintain page cache uptodate flag David Stevens
2023-02-21 22:18 ` Peter Xu [this message]
2023-02-17 10:37 ` [PATCH v4 0/3] mm/khugepaged: fix khugepaged+shmem races Miko Larsson
2023-03-03 15:35 ` Peter Xu
2023-03-03 15:45 ` Zach O'Keefe
2023-03-03 18:55 ` Yang Shi
2023-03-03 22:52 ` Andrew Morton
2023-03-06 2:44 ` David Stevens
2023-03-06 21:25 ` Andrew Morton
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=Y/VDLvLpiHkRgVjs@x1n \
--to=peterx@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=david@redhat.com \
--cc=hughd@google.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=shy828301@gmail.com \
--cc=stevensd@chromium.org \
--cc=willy@infradead.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).