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([2001:16a2:de8d:400:58:dbf8:dff9:4863]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-477558e695esm44266295e9.2.2025.11.05.05.49.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 05 Nov 2025 05:49:32 -0800 (PST) Message-ID: <017b23d3-28e1-4785-8334-b3b3f9800e2a@gmail.com> Date: Wed, 5 Nov 2025 16:49:30 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] PR_*ET_THP_DISABLE.2const: document addition of PR_THP_DISABLE_EXCEPT_ADVISED To: alx@kernel.org Cc: linux-man@vger.kernel.org, david@redhat.com, lorenzo.stoakes@oracle.com, hannes@cmpxchg.org, baohua@kernel.org, shakeel.butt@linux.dev, ziy@nvidia.com, laoar.shao@gmail.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, linux-kernel@vger.kernel.org, kernel-team@meta.com References: <20251105134811.3170745-1-usamaarif642@gmail.com> Content-Language: en-GB From: Usama Arif In-Reply-To: <20251105134811.3170745-1-usamaarif642@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 05/11/2025 16:48, Usama Arif wrote: > PR_THP_DISABLE_EXCEPT_ADVISED extended PR_SET_THP_DISABLE to only provide > THPs when advised. IOW, it allows individual processes to opt-out of THP = > "always" into THP = "madvise", without affecting other workloads on the > system. The series has been merged in [1]. Before [1], the following 2 > calls were allowed with PR_SET_THP_DISABLE: > > prctl(PR_SET_THP_DISABLE, 0, 0, 0, 0); // to reset THP setting. > prctl(PR_SET_THP_DISABLE, 1, 0, 0, 0); // to disable THPs completely. > > Now in addition to the 2 calls above, you can do: > > prctl(PR_SET_THP_DISABLE, 1, PR_THP_DISABLE_EXCEPT_ADVISED, 0, 0); // to > disable THPs except madvise. > > This patch documents the changes introduced due to the addition of > PR_THP_DISABLE_EXCEPT_ADVISED flag: > - PR_GET_THP_DISABLE returns a value whose bits indicate how THP-disable > is configured for the calling thread (with or without > PR_THP_DISABLE_EXCEPT_ADVISED). > - PR_SET_THP_DISABLE now uses arg3 to specify whether to disable THP > completely for the process, or disable except madvise > (PR_THP_DISABLE_EXCEPT_ADVISED). > > [1] https://github.com/torvalds/linux/commit/9dc21bbd62edeae6f63e6f25e1edb7167452457b > > Signed-off-by: Usama Arif > --- > v1 -> v2 (Alejandro Colomar): > - Fixed double negation on when MADV_HUGEPAGE will succeed > - Turn return values of PR_GET_THP_DISABLE into a table > - Turn madvise calls into full italics > - Use semantic newlines > --- > man/man2/madvise.2 | 6 ++- > man/man2const/PR_GET_THP_DISABLE.2const | 20 +++++++--- > man/man2const/PR_SET_THP_DISABLE.2const | 52 +++++++++++++++++++++---- > 3 files changed, 64 insertions(+), 14 deletions(-) > Resending this for review as the patch to implement this is in merged [1] [1] https://github.com/torvalds/linux/commit/9dc21bbd62edeae6f63e6f25e1edb7167452457b