From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>,
Samarth Narang <samarth.colleges@gmail.com>
Cc: Xu Xin <xu.xin@linux.dev>,
Chengming Zhou <chengming.zhou@linux.dev>,
Peter Xu <peterx@redhat.com>, Kiryl Shutsemau <kas@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Lance Yang <lance.yang@linux.dev>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v3] mm/ksm: keep soft-dirty when merging a page
Date: Sun, 25 Oct 2026 13:36:12 +0100 [thread overview]
Message-ID: <d39e7c09-7098-4563-b5fc-dc90982facee@kernel.org> (raw)
In-Reply-To: <20261023223352.c6de9f2b58fe999814e5bb17@linux-foundation.org>
On 10/24/26 07:33, Andrew Morton wrote:
> On Wed, 21 Oct 2026 11:21:57 -0700 Samarth Narang <samarth.colleges@gmail.com> wrote:
>
>> replace_page() maps the KSM page with a PTE built from scratch, so the
>> soft-dirty bit of the PTE it replaces is lost. A page written since
>> "clear_refs 4" then no longer shows as soft-dirty once it is merged, and
>> a soft-dirty based dumper treats it as unchanged.
>>
>> Copy the soft-dirty bit from the original PTE to the new PTE.
>
> Thanks. My LLM review thing says:
>
> : There's a separate, pre-existing problem with the KSM zero-page
> : path which is worth pointing out.
Cool, more AI schlop.
TL;dr Sashiko raised this before and I commented why we don't care IIRC.
--
Cheers,
David
next prev parent reply other threads:[~2026-10-26 9:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-21 18:21 Samarth Narang
2026-10-22 0:51 ` Lance Yang
2026-10-24 5:33 ` Andrew Morton
2026-10-25 12:36 ` David Hildenbrand (Arm) [this message]
2026-10-25 12:36 ` David Hildenbrand (Arm)
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