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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Jonathan Corbet , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] docs: update THP documentation to clarify sysfs "never" setting Date: Mon, 21 Jul 2025 09:27:31 -0700 Message-Id: <20250721162731.9822-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250721155530.75944-1-lorenzo.stoakes@oracle.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 659E840005 X-Stat-Signature: qp4hnq6typemn1g9pmdi69oh1e6qtjwm X-HE-Tag: 1753115255-320528 X-HE-Meta: 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 FcYx6M1e nkeiKDO8rwktDLu3CZqXXwatFT+XeZiRbZ10vGb5MiAUEAdls28QF06w4WinIW3QTDUurAoHAG7fe7Q0oek+XAWUg3yfH6fFwAXdIQoJbVKkzlbIrSrzldNrl1GYqFncKl1rpI3bm6V9PYu/Rlx+foHegtXCgSAGP7ged43hMcoldy8RPKG6ZCtSGp3Nwc3PHF2ipvkTO9q7/Xj4r6Lw6ivu7YXCsDcc7bSHMc4P+522r4BG1qyJwtYSxeDBN/XsAswqw X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 21 Jul 2025 16:55:30 +0100 Lorenzo Stoakes 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 Acked-by: SeongJae Park Thanks, SJ [...]