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 2F39F606A323 for ; Thu, 12 Nov 2026 07:54:33 +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=MoPmVb91; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Fu08OZlQ 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=1shLe9IVwY4D8MGt7zySWfM+B9KcuUz/MrZ+F8qYFDg=; b=MoPmVb91ZisCT779Sw8iZAv5W0 jlIEtHO3UgC7OWa5W/6fo3BwVk37m55akyLYWXutJNS4ZEjkBLyzSTcY5CSzWMwZfc4VLTmtKwA+m xcy5h/Nho+O+EnEiRXCekUfwJghyn476csaPVOayBUJZ/NnLlH/1cOP7bJHfuVyqNJ0AdyI52F+2l p5fKJXPHg5oCcULR2y1jLLjf+5gfqJmFc55gHUdGIvVBFfqGCOo0VOsIi/4ruUfIkaGjlaU+YTWqd gMLrrqEtzYCDxVPpCkOE67V6u+3f0H3TPs/erxOKEUi+mQu4FjVEUNJOPn50D8fSZpb3Mg7MYA4/O HpBcmATg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xRPdZ-00000008yvO-2CR6; Thu, 12 Nov 2026 07:54:32 +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 1xRPdN-00000008ynE-47Js for kexec@lists.infradead.org; Thu, 12 Nov 2026 07:54:16 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id BB41E439AD; Thu, 12 Nov 2026 07:54:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AD0B1F00A05; Thu, 12 Nov 2026 07:54:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794470053; bh=1shLe9IVwY4D8MGt7zySWfM+B9KcuUz/MrZ+F8qYFDg=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Fu08OZlQ8jv8r8a4aCD6T9xznGvhCR3J/+EtYeo9RgUgjQPd2TwRcGcIRw5lNN7GC K9trgRaolwg+mZfslPsUBLVX+oX9dbnkUn33AFayt0XCe2Ae1izF5s+KVyl6s/iOtY K6++d+2r0Jk/a+OXeG9FWCncQZb1V3DsfI1F0wy0bAbfdz6jI8bybEEAuQJKdiWhKr YMtdxMUOiaSB6VapNIjUoxaTzTQoI8NziP6eKRT+qfoMVGImJXhxAkbfxU8J1Fp3qQ PXvBRjhcTfZqDVIusrnQaCYE9/MjQ3uS4kqxF+TdsQcjl/g6eRiFIeb8KgIEHlhiIz 60cPvTjv3ORVA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 7/9] kho: Report how much handover memory is preserved and restored To: "Chris Down" , "Pasha Tatashin" , "Mike Rapoport" , "Pratyush Yadav" Cc: "Alexander Graf" , "Baoquan He" , "Jonathan Corbet" , "Shuah Khan" , kexec@lists.infradead.org, kernel-team@meta.com In-Reply-To: <920192d01c6534b5754648e12840f73cdcfa73de.1794383544.git.chris@chrisdown.name> References: <920192d01c6534b5754648e12840f73cdcfa73de.1794383544.git.chris@chrisdown.name> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 12 Nov 2026 07:54:12 +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: > Most memory the previous kernel preserved stays reserved until its user > restores it through KHO, either to use it again or to free it. If > nothing does, it stays reserved for as long as the kernel runs. On a > hypervisor host that can be gigabytes, but amusingly nothing really > shows it reliably. The host simply has less memory than it should, which > is not exactly obvious. >=20 > All preserved memory is reserved in kho_preserved_memory_reserve(), and > everything restored through KHO goes through kho_restore_page(), so KHO > can count both easily. Let's add preserved_size and restored_size, in > bytes, to /sys/kernel/kexec/kho_incoming/. >=20 > For example, after a live update preserving a 64 MiB memfd: >=20 > preserved_size restored_size > before retrieval 67403776 8192 > after retrieval 67403776 67395584 >=20 > The 8 KiB left are the incoming KHO FDT and LUO's FLB header. >=20 > Signed-off-by: Chris Down Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/cover.1794383544.gi= t.chris@chrisdown.name?part=3D7