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 0B799314A67 for ; Thu, 27 Nov 2025 20:55:40 +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=1764276941; cv=none; b=UqbLAMBs22A0tFVz65J88nRfTuZPWXmUcXEyaO8RXrQtaOaFXuhpY8cCFATgrXwl+c7+ksnXNA9Gbju9QP7eCem59MGTn2c5puWH2z7vsrYiO+UMnyhEyyUvB3PEboinCsI6SED2huD/VQtOiYZIWKb8YMyMGUK1FY/YH/sqEkM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764276941; c=relaxed/simple; bh=nBbha1Hg4kcAxAX2ukBFkZ6T2IVL+O9Lvml/KMHDqB8=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=X3Uq1lXyb3ifOdE3qUEEf6KtbQau+qAxlan7C/tdk0UfP1PC+52jJPO6tGj5+skQ+RgP/rdxpHHN8H+dMlHODqYj/IoctPi7T8r4aR4qOZFuQbv3bfkiluWCHD5EUxkBDGSO03CjRksut5LbTZkTvsZmZHPAst703XF4uL3W7gU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=h7KdYcYZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="h7KdYcYZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1BD88C4CEF8; Thu, 27 Nov 2025 20:55:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1764276940; bh=nBbha1Hg4kcAxAX2ukBFkZ6T2IVL+O9Lvml/KMHDqB8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=h7KdYcYZ4TuJrTT9jdQuQQl1OLRj2Xne9zxcLYqOohZYz1j1dBAGVGbe7q3J1Bpdv v7jCIZsl8PHuZG5EpHnuXqatbF+AOqG4GSdNAN4Y+ikB5K7S/3k88KgcRHrTma5RtC YVyTej0OP9knbwCn5qxky/lVy9SQCIiEBEYCSkRY= Date: Thu, 27 Nov 2025 12:55:39 -0800 From: Andrew Morton To: Usama Arif Cc: rppt@kernel.org, kas@kernel.org, changyuanl@google.com, graf@amazon.com, leitao@debian.org, thevlad@meta.com, pratyush@kernel.org, dave.hansen@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v2 2/2] mm/memblock: only mark/clear KHO scratch memory when needed Message-Id: <20251127125539.98b2f148c6225f1cb7c9d045@linux-foundation.org> In-Reply-To: <20251127203724.3177621-3-usamaarif642@gmail.com> References: <20251127203724.3177621-1-usamaarif642@gmail.com> <20251127203724.3177621-3-usamaarif642@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 27 Nov 2025 20:33:20 +0000 Usama Arif wrote: > The scratch memory for kexec handover is used to bootstrap the > kexec'ed kernel. It is only needed when CONFIG_KEXEC_HANDOVER > is enabled and only if it is a KHO boot. Add checks to prevent > marking a KHO scratch region unless needed. What effect does this change have? Lessened memory consumption, presumably. Of what magnitude and for what time period?