From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
To: Barry Song <21cnbao@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>, Zi Yan <ziy@nvidia.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-mm@kvack.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH] docs: update THP documentation to clarify sysfs "never" setting
Date: Wed, 23 Jul 2025 16:41:50 +0100 [thread overview]
Message-ID: <d5211214-183a-4a13-80a5-1434aca785f4@lucifer.local> (raw)
In-Reply-To: <c071c478-c6c3-47c4-a504-b1fa650d528f@lucifer.local>
On Tue, Jul 22, 2025 at 06:29:15AM +0100, Lorenzo Stoakes wrote:
> Re: man page - I _do_ intend to update the man page as I find it far too
> vague on this topic currently, so that patch will be coming soon.
Actually:
MADV_COLLAPSE is independent of any sysfs (see sysfs(5))
setting under /sys/kernel/mm/transparent_hugepage, both in
terms of determining THP eligibility, and allocation
semantics. See Linux kernel source file
Documentation/admin-guide/mm/transhuge.rst for more
information. MADV_COLLAPSE also ignores huge= tmpfs mount
when operating on tmpfs files. Allocation for the new
hugepage may enter direct reclaim and/or compaction,
regardless of VMA flags (though VM_NOHUGEPAGE is still
respected).
I think this is clear enough to require no update.
THe confusion arose from the doc page seemingly contradicting this. By
referring to the doc page which now makes things clear, we're all good! :)
Cheers, Lorenzo
next prev parent reply other threads:[~2025-07-23 15:42 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-21 15:55 [PATCH] docs: update THP documentation to clarify sysfs "never" setting Lorenzo Stoakes
2025-07-21 16:27 ` SeongJae Park
2025-07-22 1:13 ` Zi Yan
2025-07-22 1:30 ` Baolin Wang
2025-07-22 2:23 ` Barry Song
2025-07-22 2:33 ` Baolin Wang
2025-07-22 3:37 ` Barry Song
2025-07-22 5:29 ` Lorenzo Stoakes
2025-07-23 15:41 ` Lorenzo Stoakes [this message]
2025-07-22 5:24 ` Lorenzo Stoakes
2025-07-22 5:25 ` Lorenzo Stoakes
2025-07-22 5:34 ` Lorenzo Stoakes
2025-07-22 5:59 ` Baolin Wang
2025-07-22 8:19 ` Barry Song
2025-07-22 7:20 ` David Hildenbrand
2025-07-22 7:59 ` David Hildenbrand
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