From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EAB4C35FFC for ; Tue, 25 Mar 2025 15:04:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8EC7B28003D; Tue, 25 Mar 2025 11:04:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 875AB28000C; Tue, 25 Mar 2025 11:04:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7174F28003D; Tue, 25 Mar 2025 11:04:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 5383C28000C for ; Tue, 25 Mar 2025 11:04:01 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id BE4C480823 for ; Tue, 25 Mar 2025 15:04:01 +0000 (UTC) X-FDA: 83260393482.09.7FF2396 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf16.hostedemail.com (Postfix) with ESMTP id EAE3318002D for ; Tue, 25 Mar 2025 15:03:59 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=pUrY9lz+; spf=pass (imf16.hostedemail.com: domain of rppt@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1742915040; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=DlSm/XJ+691y9WK83MK+K+VAhVyt9Uh+O14MYitCEMU=; b=PR3r4Wd7yNT0ah7AZvx1Uynlx1Khqz87d+UT5VNxsVacR2NKvs240E9AsDM2HcD114a3LB 18fQz+Ssnq2KrkkxE3dHyhEMYQBu0QzNpuArailQQzfkwbuZFneF4a9O2++WwoJDAtNH7Z WwBQKKBrw0eu9HdOMY2v+dlbfi7Lta0= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1742915040; a=rsa-sha256; cv=none; b=eBrCatnKNoRNGq+NiHvKdqd/M8bDAckMeta3ZQAtgI+j7GNOc9kGF1qIMYE6UDfaSVpIEX u9bdikHWuVK88G20bhaNTpwUL7nJHloIAW9NhZp5lXOMtEhGwxzXP+6QAvnFlcPLi6nebu HuChw1ctjPWICGRItADgy9RSjIIVtQ0= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=pUrY9lz+; spf=pass (imf16.hostedemail.com: domain of rppt@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id CC9F55C5DD3; Tue, 25 Mar 2025 15:01:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1174BC4CEEE; Tue, 25 Mar 2025 15:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742915038; bh=DlSm/XJ+691y9WK83MK+K+VAhVyt9Uh+O14MYitCEMU=; h=Date:From:To:CC:Subject:In-Reply-To:References:From; b=pUrY9lz+D3qAxxjKU9sRrd3biaS0OmEhrrBkwmx4kPkTpUCMHpy/mzaWypb8rfZ4e WLOGhPmrBt3fs8APit625QUMpFR+e16CpN6BEITDKRtEtwtexF6oaMn3wIkjYwgOeN 6FizHB25INbj95+5G1l44Aav81PK0heFxnEewIbWf7WuxLUokYDYAlKxW2nVNlvXo0 +ZLGoHASqyFS74gwKSkv05fI01LQ9Iii2kDieVumQb9V4b3kd16w0Zxcxjv9wGWtEc lDYZMXceQTr71M7lM3D0LYTuesBJusjWuB+LWuX05PUAjv37EulHMnN5n7zgzuy3C2 93XGDsyQIeifg== Date: Tue, 25 Mar 2025 11:03:21 -0400 From: Mike Rapoport To: Pasha Tatashin , Changyuan Lyu CC: linux-kernel@vger.kernel.org, graf@amazon.com, akpm@linux-foundation.org, luto@kernel.org, anthony.yznaga@oracle.com, arnd@arndb.de, ashish.kalra@amd.com, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, dwmw2@infradead.org, ebiederm@xmission.com, mingo@redhat.com, jgowans@amazon.com, corbet@lwn.net, krzk@kernel.org, mark.rutland@arm.com, pbonzini@redhat.com, hpa@zytor.com, peterz@infradead.org, ptyadav@amazon.de, robh+dt@kernel.org, robh@kernel.org, saravanak@google.com, skinsburskii@linux.microsoft.com, rostedt@goodmis.org, tglx@linutronix.de, thomas.lendacky@amd.com, usama.arif@bytedance.com, will@kernel.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org Subject: Re: [PATCH v5 00/16] kexec: introduce Kexec HandOver (KHO) User-Agent: K-9 Mail for Android In-Reply-To: References: <20250320015551.2157511-1-changyuanl@google.com> Message-ID: <01864D3D-C935-4AA6-85A9-363B14EA5443@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: EAE3318002D X-Stat-Signature: ishyt9etpsqq6ijwtg4pu3p9e3y9mr81 X-HE-Tag: 1742915039-69425 X-HE-Meta: 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 ZllC66lV 6OIOng0C9hCj0HubPEF3xPznVDelPrOsuCgRQCCRZAq3wLCzCL+PFJvtWFzZH7ZCEWUw18BWKfDGE0+RTNTTnvixwVNS5C7xwDKH87MIh7LbDZHLFRhRq0xdUjRdT4yRQYuIFQy1DWcnhWQGwM++1rmxp2zQiCBJnAq3Cz+nifdRmUE9yecIAfb5WXA8sy5nG2ZZO9i42wryeeUI31ZknhQ+Ms9uuPTLuPli8HXl2+0e5xbxh2bCdwW3Z9aTcgoC3IqKfjndDi5fp7noMqpyxVZJVZrctQGeHkTVagX9Xxzscyq+twGeODWLErt1ycZCxJt7PDFa4J6yiLck8w6a7iBCOBNYqmDCLrmqq 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 March 25, 2025 10:19:53 AM EDT, Pasha Tatashin wrote: >> To use the code, please boot the kernel with the "kho=3Don" command lin= e >> parameter=2E >> KHO will automatically create scratch regions=2E If you want to set the >> scratch size explicitly you can use "kho_scratch=3D" command line param= eter=2E >> For instance, "kho_scratch=3D16M,512M,256M" will reserve a 16 MiB low >> memory scratch area, a 512 MiB global scratch region, and 256 MiB >> per NUMA node scratch regions on boot=2E > >kho_scratch=3D is confusing=2E It should be renamed to what this memory >actually represents, which is memory that cannot be preserved by KHO=2E > >I suggest renaming all references to "scratch" and this parameter to: > >kho_nopersistent=3D or kho_nopreserve=3D I'm leaning towards kho_bootstrap >This way, we can also add checks that early allocations done by the >kernel in this memory do not get preserved=2E We can also add checks to >ensure that scarce low DMA memory does not get preserved across >reboots, and we avoid adding fragmentation to that region=2E > >Pasha > --=20 Sincerely yours, Mike