From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BBD6B13635E; Wed, 18 Mar 2026 03:54:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773806042; cv=none; b=uHOVlMCupaSjrRnAkgfGbFUt2bqTzy7nvyuvF+8P5aBBa8mKfXSrqPBOD0OMuxcwmkPsXUglHhhhPb+Xy39/ZY6KFAbML1FzXSu2kcZKZDboh1pj/w7nyjNTykb8AIx68HHgEtLdxQy+zZU/9yIrbjc8m31LcW4NG+ya1mNTRaE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773806042; c=relaxed/simple; bh=6CatznSLTNYV80vtabVt4rhKS2msE5JzlPGM+/AcAPM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=AMTF3b0H+IChkZZwsSNg3HmN1z+obMU7xuYxs+MQAaZ375VTgQ2DJVCJn5p8pHfuGkgrLfIsAKENAXXB9fkpSzwR/JUlN/avra2FFSmvxRJ2VBF6+9Feo6v2+xoVmK/5Ylxum4KU+tluorBzUPq01z0oSo5cobyMxWFBBeVQeo0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gCFRJ0rv; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gCFRJ0rv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7DDCC19421; Wed, 18 Mar 2026 03:54:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773806042; bh=6CatznSLTNYV80vtabVt4rhKS2msE5JzlPGM+/AcAPM=; h=From:To:Cc:Subject:Date:From; b=gCFRJ0rvMNhZZOKla+65Id6mo9bEnsay0KZtgmg2nEc6VVIzC5cFtHevqyv52Rksi r9ADgxA+jitpnSqdWc3Eli8zBEWQMZwPpp0gbyUi7+01NwJP71eBwMHEpTStmkvGtB cJego1Qs71MlgERmEFO6zXeJVvHVOHVaXA/EzT8ll6sJuhFyyRknQzWK/knQ2caqGw V4V05yPZfzLbnHGPi4ShQPpqOCmnZ8TP/NbeLDxnbGfxrUEVu4Ie9CpXaXL595Q3YK LF3iajum8gCSHtU3del9g4xuaOhFOcumXDIxP3OoqpY9HBS1PzvxUDJSb9ngCVglSe /enH9MZq/cLrw== From: SeongJae Park To: Andrew Morton Cc: Asier Gutierrez , "Liam R. Howlett" , David Hildenbrand , Jonathan Corbet , Lorenzo Stoakes , Michal Hocko , Mike Rapoport , SeongJae Park , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , damon@lists.linux.dev, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2] Docs/mm/damon/design: document DAMON actions when TRANSPARENT_HUGEPAGE is off Date: Tue, 17 Mar 2026 20:53:47 -0700 Message-ID: <20260318035349.88715-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Asier Gutierrez MADV_HUGEPAGE and MADV_NOHUGEPAGE are guarded and they are not available when compiling the kernel without TRANSPARENT_HUGEPAGE option. The DAMON behaviour is to silently fail [1] in when DAMOS_HUGEPAGE or DAMOS_NOHUGEPAGE are used, but TRANSPARENT_HUGEPAGE is disabled. Update the DAMON documentation to reflect this behaviour. [1]: https://lore.kernel.org/66131775-180b-4b9f-b7ce-61a3e077b6e6@huawei-partners.com/ Signed-off-by: Asier Gutierrez Reviewed-by: SeongJae Park Signed-off-by: SeongJae Park --- Changes from v1 (https://lore.kernel.org/20260316140822.2033181-1-gutierrez.asier@huawei-partners.com) - Wordsmith description. - Rebase to latest mm-new. Documentation/mm/damon/design.rst | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst index dc37402c0fee9..838b14d225193 100644 --- a/Documentation/mm/damon/design.rst +++ b/Documentation/mm/damon/design.rst @@ -460,9 +460,13 @@ that supports each action are as below. - ``pageout``: Reclaim the region. Supported by ``vaddr``, ``fvaddr`` and ``paddr`` operations set. - ``hugepage``: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``. - Supported by ``vaddr`` and ``fvaddr`` operations set. + Supported by ``vaddr`` and ``fvaddr`` operations set. When + TRANSPARENT_HUGEPAGE is disabled, the application of the action will just + fail. - ``nohugepage``: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``. - Supported by ``vaddr`` and ``fvaddr`` operations set. + Supported by ``vaddr`` and ``fvaddr`` operations set. When + TRANSPARENT_HUGEPAGE is disabled, the application of the action will just + fail. - ``lru_prio``: Prioritize the region on its LRU lists. Supported by ``paddr`` operations set. - ``lru_deprio``: Deprioritize the region on its LRU lists. base-commit: 809b8b9fc1374abb1b1b50fbd0260085b0832b2e -- 2.47.3