From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Baolin Wang <baolin.wang@linux.alibaba.com>,
akpm@linux-foundation.org, hughd@google.com
Cc: ziy@nvidia.com, liam@infradead.org, nico.pache@linux.dev,
ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org,
lance.yang@linux.dev, usama.arif@linux.dev, kas@kernel.org,
ljs@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm: shmem: ignore sysfs configs for shmem forced collapse
Date: Fri, 25 Sep 2026 13:29:11 +0200 [thread overview]
Message-ID: <66f5a0c2-6adb-4e03-9225-cf566b7f76f8@kernel.org> (raw)
In-Reply-To: <063f655b4d6c4234f3aa27ed6ecab10283ecb880.1789351825.git.baolin.wang@linux.alibaba.com>
On 9/14/26 04:12, Baolin Wang wrote:
> According to Documentation/mm/transhuge.rst, MADV_COLLAPSE is expected to
> ignore any THP or mTHP interface settings.
>
> However, after commit 26c7d8413aaf ("mm: thp: support "THPeligible" semantics
> for mTHP with anonymous shmem"), performing MADV_COLLAPSE on shmem will
> depend on /sys/.../hugepages-2048kB/shmem_enabled being set to "inherit"
> (although that is the default), which can cause MADV_COLLAPSE to fail
> unexpectedly.
>
> Fix this by returning the result of shmem_huge_global_enabled() directly
> when MADV_COLLAPSE is requested, allowing PMD-order collapse while ignoring
> shmem THP/mTHP settings.
>
> Fixes: 26c7d8413aaf ("mm: thp: support "THPeligible" semantics for mTHP with anonymous shmem")
> Reported-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
> Closes: https://lore.kernel.org/all/20260908125105.1510704-7-kirill@shutemov.name/
> Reviewed-by: Kiryl Shutsemau (Meta) <kas@kernel.org>
> Acked-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Lance Yang <lance.yang@linux.dev>
> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> ---
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
--
Cheers,
David
next prev parent reply other threads:[~2026-09-25 14:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-14 2:12 Baolin Wang
2026-09-14 2:23 ` Barry Song
2026-09-14 2:43 ` Andrew Morton
2026-09-14 3:40 ` Baolin Wang
2026-09-14 3:09 ` Qi Zheng
2026-09-25 11:29 ` David Hildenbrand (Arm) [this message]
2026-09-25 14:19 ` Lorenzo Stoakes (ARM)
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=66f5a0c2-6adb-4e03-9225-cf566b7f76f8@kernel.org \
--to=david@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=baohua@kernel.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=dev.jain@arm.com \
--cc=hughd@google.com \
--cc=kas@kernel.org \
--cc=lance.yang@linux.dev \
--cc=liam@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=nico.pache@linux.dev \
--cc=ryan.roberts@arm.com \
--cc=usama.arif@linux.dev \
--cc=ziy@nvidia.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®