linux-kernel - Re: [PATCH] docs: update THP documentation to clarify sysfs "never" setting

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Message-Id: <20250721162731.9822-1-sj@kernel.org>
Date: Mon, 21 Jul 2025 09:27:31 -0700
From: SeongJae Park <sj@...nel.org>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: SeongJae Park <sj@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Hildenbrand <david@...hat.com>,
	Zi Yan <ziy@...dia.com>,
	Baolin Wang <baolin.wang@...ux.alibaba.com>,
	"Liam R . Howlett" <Liam.Howlett@...cle.com>,
	Nico Pache <npache@...hat.com>,
	Ryan Roberts <ryan.roberts@....com>,
	Dev Jain <dev.jain@....com>,
	Barry Song <baohua@...nel.org>,
	Jonathan Corbet <corbet@....net>,
	linux-mm@...ck.org,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] docs: update THP documentation to clarify sysfs "never" setting

On Mon, 21 Jul 2025 16:55:30 +0100 Lorenzo Stoakes <lorenzo.stoakes@...cle.com> wrote:

> Rather confusingly, setting all Transparent Huge Page sysfs settings to
> "never" does not in fact result in THP being globally disabled.
> 
> Rather, it results in khugepaged being disabled, but one can still obtain
> THP pages using madvise(..., MADV_COLLAPSE).
> 
> This is something that has remained poorly documented for some time, and it
> is likely the received wisdom of most users of THP that never does, in
> fact, mean never.
> 
> It is therefore important to highlight, very clearly, that this is not the
> ase.

case?

> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>

Acked-by: SeongJae Park <sj@...nel.org>


Thanks,
SJ

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