From: Matthew Wilcox <willy@infradead.org>
To: Pedro Falcato <pfalcato@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <ljs@kernel.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Liam R. Howlett" <liam@infradead.org>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, stable@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Song Liu <song@kernel.org>,
Eric Hagberg <ehagberg@janestreet.com>, Zi Yan <ziy@nvidia.com>,
Gregg Leventhal <gleventhal@janestreet.com>
Subject: Re: [PATCH stable] mm/khugepaged: write all dirty file folios when collapsing
Date: Sat, 4 Jul 2026 01:50:03 +0100 [thread overview]
Message-ID: <akhYu66GmjyM8l6a@casper.infradead.org> (raw)
In-Reply-To: <20260702165409.164568-1-pfalcato@suse.de>
On Thu, Jul 02, 2026 at 05:54:09PM +0100, Pedro Falcato wrote:
> +++ b/mm/khugepaged.c
> @@ -2094,32 +2094,43 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr,
> goto xa_unlocked;
> }
>
> - if (!is_shmem) {
> +xa_locked:
> + xas_unlock_irq(&xas);
> +xa_unlocked:
Hmm. Before this patch, we increment nr_thps while holding the i_pages
lock. Now we aren't holding it, but we are holding the invalidate lock.
Can you put something in the commit message that notes this change and
argues that it's totally fine actually?
You were good enough to not point out that my suggestion of calling
write_and_wait in the existing !is_shmem condition would result in
sleeping with a spinlock held. Silly me ;-)
prev parent reply other threads:[~2026-07-04 0:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-02 16:54 [PATCH stable] mm/khugepaged: write all dirty file folios when collapsing Pedro Falcato
2026-07-02 17:24 ` Zi Yan
2026-07-03 2:53 ` Lance Yang
2026-07-03 9:19 ` Pedro Falcato
2026-07-03 3:49 ` Baolin Wang
2026-07-03 8:45 ` Lance Yang
2026-07-03 9:17 ` Pedro Falcato
2026-07-03 5:11 ` Lance Yang
2026-07-03 9:18 ` Pedro Falcato
2026-07-03 8:55 ` David Hildenbrand (Arm)
2026-07-03 9:02 ` Lance Yang
2026-07-03 9:20 ` David Hildenbrand (Arm)
2026-07-04 0:50 ` Matthew Wilcox [this message]
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