From: Matthew Wilcox <willy@infradead.org>
To: Kiryl Shutsemau <kirill@shutemov.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Ilya Gladyshev <ilya.gladyshev@linux.dev>,
Lorenzo Stoakes <ljs@kernel.org>,
Luis Chamberlain <mcgrof@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: Re: Improve page refcount scalability
Date: Wed, 14 Oct 2026 16:28:42 +0100 [thread overview]
Message-ID: <as-fqjiGj5T5NLOe@casper.infradead.org> (raw)
In-Reply-To: <as9rk-T5cedl8Myq@thinkstation>
On Wed, Oct 14, 2026 at 12:53:11PM +0100, Kiryl Shutsemau wrote:
> The uptodate check in filemap_read_rcu_can_copy() has to stay, though.
> The flag only says the folio was uptodate when it was marked. Some
> filesystems clear PG_uptodate on a folio that stays in the page cache,
> and that can happen after the folio got the flag.
Those filesystems are buggy. We have assertions that the uptodate flag
is set on folios mapped into userspace, and filesystems going arund
clearing the uptodate bit will cause problems. It's something I'm
working on removing, but since it's all connected to writeback errors,
it takes a lot of arguing with each filesystem maintainer.
next prev parent reply other threads:[~2026-10-14 15:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-13 18:43 Linus Torvalds
2026-10-13 21:03 ` Matthew Wilcox
2026-10-13 21:26 ` Linus Torvalds
2026-10-13 23:20 ` Paul E. McKenney
2026-10-14 10:36 ` Kiryl Shutsemau
2026-10-14 10:46 ` David Hildenbrand (Arm)
2026-10-13 22:43 ` Kiryl Shutsemau
2026-10-13 23:39 ` Linus Torvalds
2026-10-14 11:53 ` Kiryl Shutsemau
2026-10-14 15:28 ` Matthew Wilcox [this message]
2026-10-14 0:10 ` Harry Yoo
2026-10-14 1:01 ` Linus Torvalds
2026-10-14 13:59 ` Pedro Falcato
2026-10-14 16:25 ` Linus Torvalds
2026-10-14 16:59 ` Linus Torvalds
2026-10-14 17:15 ` Linus Torvalds
2026-10-14 17:43 ` Kirill A. Shutemov
2026-10-14 18:24 ` Linus Torvalds
2026-10-15 2:12 ` Jaegeuk Kim
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