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 0EF54606A89F for ; Thu, 12 Nov 2026 10:47:59 +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=POvkzBGQ; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=hDkP6biZ 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:Cc:To:Subject: From:Message-ID: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=oFKR9yNEKumpUkj+R+V7Il5eKMS7QYAR0aRlqbeK+Xs=; b=POvkzBGQEfCJdls1r91swagTSh SrMGZldNwaSLjaAiqc98I4bj+og7RkckHWt72EMpzZTvUygpABGm7g/X32/6ZipckqgDJWobhVnLK ipZKDOuwRxpQkrSdLMBoclSxD594mQ6TduH2Og2B4r8enKRLLTTrIzgdYt2JslN2M3HCKOS5P3GwJ ANq1EE84pekgndfhL9gInhsvU2YdloHgCL5/++8Fe0Dkp0tgQzQdPI1H8qKI6hBDYocWTT26oKK4w ValJJFYvirfhpEmKVQ/cYDb07ox3jbSzirf2jjbSSfEo2uc/ec1qqda+bxlDsfCOkn+ltEEUxW7RW wPTU1PzQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRSLW-00000009aMC-1Gct; Thu, 12 Nov 2026 10:47:58 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRSLR-00000009aKp-3851 for kexec@lists.infradead.org; Thu, 12 Nov 2026 10:47:54 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 104DE6122A; Thu, 12 Nov 2026 10:47:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 126BE1F00A06; Thu, 12 Nov 2026 10:47:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794480472; bh=oFKR9yNEKumpUkj+R+V7Il5eKMS7QYAR0aRlqbeK+Xs=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=hDkP6biZ0VPsL6SM5KJYZ/0cpmg3Wl0D3r9JZfIRlSu4jmwoW9X61fmK65B+XBQJ/ YNnGU21TUV+VPYescsXRXva/bFSHK+Kgv/PEz/IIyJ3gkiIKqOVwwJQO1p9IAEdNe3 NRVlJAvrdyEInIaoYNJGHXKHxFxrxL1NnzIBxiW/o1GZh6w7aHTYq1/Ozu3kP/cvQz aCjdVS3cuOdNZKg+5GKrcP+Ts5EQ8Dj5lUsf/n8QqJPnElCdbeQfkxsDHnveUhzTZw EO/9wteU0lvOQ5vRvn7D8xVVqmgtWr2MBw0GcycwglzR5VBATAtecwui4n3FEbCqyE iEkyiXxRTcZ0Q== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 3/5] kho: skip zero-sized lowmem and global bootmem areas To: =?utf-8?b?TWlrZSBSYXBvcG9ydCAoTWljcm9zb2Z0KQ==?= , "Jonathan Corbet" , "Pasha Tatashin" , "Pratyush Yadav" Cc: "Alexander Graf" , "Andrew Morton" , "Chen Pei" , "George Guo" , "Kexin Liu" , "Randy Dunlap" , "Shuah Khan" , "Sourabh Jain" , kexec@lists.infradead.org, "Jose A. Perez de Azpillaga" , "Mukesh Pilaniya" In-Reply-To: <20261112-kho-bootmem-sizing-v3-3-f0c8d00295d5@kernel.org> References: <20261112-kho-bootmem-sizing-v3-0-f0c8d00295d5@kernel.org> <20261112-kho-bootmem-sizing-v3-3-f0c8d00295d5@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 12 Nov 2026 10:47:51 +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: > The lowmem and the global bootmem areas can have zero size, for example > when none or all of the memory is below ARCH_LOW_ADDRESS_LIMIT, or when > either of those areas is explicitly set to zero with kho_bootmem=3D. >=20 > For a zero-sized allocation memblock returns an address without reserving > anything, and that empty area is recorded in kho_bootmem. If there is no > memory below ARCH_LOW_ADDRESS_LIMIT, allocation of the empty lowmem area > fails and KHO gets disabled. >=20 > Extract a helper that checks for zero size and allocates memory from > memblock, and use it to skip empty areas the same way as empty per-node > areas are skipped. >=20 > Fixes: 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers") > Reported-by: Chen Pei > Closes: https://lore.kernel.org/all/20261026131851.9942-1-cp0613@linux.al= ibaba.com > Reviewed-by: Pasha Tatashin > Reviewed-by: Jose A. Perez de Azpillaga > Reviewed-by: Pratyush Yadav > Reviewed-by: Mukesh Pilaniya > Signed-off-by: Mike Rapoport (Microsoft) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261112-kho-bootme= m-sizing-v3-0-f0c8d00295d5@kernel.org?part=3D3