From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C8DCE606A31C for ; Mon, 9 Nov 2026 20:07:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=cqLG94JG; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=oca6mWTB DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:To:Subject:From :Message-ID:Cc:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=W700b5s8KiMkhov29D/Y1x2mk9mtS9WQJC6wHJxk7+0=; b=cqLG94JGgqT4/tERk+BgTazLql tcZGt6uwJsl6wTTqXOHCPM92matpDMr/f7z65z6VgN6s4JYz3Y+/B2ihpenZX2m3izACaMKdyjzCK h9L/8dL3+Cf5RbFGpnRPvzh/DhFTRqXS8oXzJ5YAMj9LyRLKsxygXtENs+uGouirBHGZ/MDTG35O+ qQny2220BCUjfAdg56skVgUaQYoZyPK9KgubET1V6GGgnK8QEgzbqFsKiIBRa3tLwtGSFVuqpdgOk 6qYD0gnFdQgm8nwsF1mau/cwImoBNPRvO9NncRUpKZTBexT+V9pGsJLYASGyvVOG9MTI6JhDOXJ20 zWclkA4A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xQVeg-00000001cCj-2tW7; Mon, 09 Nov 2026 20:07:50 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xQVef-00000001cCD-2DZ3 for kexec@lists.infradead.org; Mon, 09 Nov 2026 20:07:49 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 4B31441411; Mon, 9 Nov 2026 20:07:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 187741F0089F; Mon, 9 Nov 2026 20:07:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794254869; bh=W700b5s8KiMkhov29D/Y1x2mk9mtS9WQJC6wHJxk7+0=; h=From:Subject:Reply-To:To:In-Reply-To:References:Date; b=oca6mWTB3dQNdjbWLB8CKKA0PvVeN1ymZcJ1qA9YuDVXWu4udObfW1RhGT3MDHf+2 i7+hDUIDo9UIgpRnznbzYJgIS35HOkVDgjRworq0rhL7EVUeD63ZgmzeSTyEprOLl0 U4eFRK/YYC+1aejzh8+GYrYqJgjXNfh47oH1VHKesejXfp9EJDr6oZh+9B7Y3kwCrR 6cdbejV4AQQw1sJ1tsJiR82spMiqrtq7qgIYGwagDKUvFUY5fdX70Tn5dEYo+oNajL rFHvPWsTET3oeQqkZCgneCRUPiJ15Fco5tE5VGfW64lOXji52xKpJD5o9oEZ3rTHZ4 MHE+DQV6iHnOQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2] mm/hugetlb: allow crashkernel to reuse hugetlb CMA memory To: "Usama Arif" , "Andrew Morton" , baoquan.he@linux.dev, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, muchun.song@linux.dev, osalvador@suse.de, david@kernel.org, jbohac@suse.cz, sourabhjain@linux.ibm.com, ruanjinjie@huawei.com, leitao@debian.org, kexec@lists.infradead.org, kas@kernel.org, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, zaslonko@linux.ibm.com, brads@mainlining.org, kernel-team@meta.com In-Reply-To: <20261106165142.2847916-1-usama.arif@linux.dev> References: <20261106165142.2847916-1-usama.arif@linux.dev> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 09 Nov 2026 20:07:47 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > crashkernel=3Dsize,cma reserves a separate CMA pool. On systems that > already reserve several gigabytes with hugetlb_cma=3D (which is common in > the Meta fleet), the crash kernel cannot use that existing memory as > part of its working set. With hugetlb_cma=3D6G, requesting another 2G > with crashkernel=3D2G,cma brings the total CMA reservation to 8G, none of > which can serve unmovable kernel allocations. >=20 > Use existing HugeTLB CMA memory first for crashkernel=3Dsize,cma and > reserve dedicated CMA areas only for the remainder. With hugetlb_cma=3D6G, > a 2G request reuses 2G without reserving more CMA. With hugetlb_cma=3D2G, > a 4G request reuses 2G and reserves another 2G. >=20 > The full HugeTLB CMA pool remains available to HugeTLB and movable > allocations during normal operation. After a crash, the capture kernel > can use the selected ranges as working memory. The conventional > [ ... ] > CMA alignment, and report any shortfall. Ignore malformed optional sizes > and reject requests that would overflow page rounding. >=20 > Suggested-by: Breno Leitao > Signed-off-by: Usama Arif Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261106165142.2847= 916-1-usama.arif@linux.dev?part=3D1