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 664ECC4332F for ; Thu, 3 Nov 2022 16:40:33 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id ED8FC6B0072; Thu, 3 Nov 2022 12:40:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E89886B0073; Thu, 3 Nov 2022 12:40:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D51816B0074; Thu, 3 Nov 2022 12:40:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id C3BF06B0072 for ; Thu, 3 Nov 2022 12:40:32 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id A186C414CC for ; Thu, 3 Nov 2022 16:40:32 +0000 (UTC) X-FDA: 80092694304.18.F8CE95D Received: from mail-pl1-f175.google.com (mail-pl1-f175.google.com [209.85.214.175]) by imf05.hostedemail.com (Postfix) with ESMTP id 400F8100002 for ; Thu, 3 Nov 2022 16:40:32 +0000 (UTC) Received: by mail-pl1-f175.google.com with SMTP id 4so2498140pli.0 for ; Thu, 03 Nov 2022 09:40:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=zZXbeTNxYGfebgmrJLDuDejr3HgrFhPDQnfu9126FIM=; b=GjBeokYZM3qLZGAAUM+RKZQt0Bn/gpCNPG2HO6oqRaTaGJoYhnNyCOuXf1XHbx1v4N TQx6Pz/AQuI6R/h9cZ1cmYEP0cQKDeXlXqW5xn0tRbxir33l6Goh51aeJIsfTBD74Fu4 vNlbTi5OnEBSxsA0pS0bm+ZbDlhgMoRKOQ5Os1qSsFAlUr0sIw1i2U3zxAtN/jA1pVP9 ObpCDftLS4Yb9SNDjdOfgQ/deianIgda5F/lVnUCBqcVtPaiXc/59BI/XgJl0cdOlYQE PTWiw3ajZT9iG/2QyAgQzVFEC//f/Kis3jLsXh34FOVzrBgUdqZcYVtHn1bej36LUVvN QZMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=to:references:message-id:content-transfer-encoding:cc:date :in-reply-to:from:subject:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=zZXbeTNxYGfebgmrJLDuDejr3HgrFhPDQnfu9126FIM=; b=RBinKqtHlllG+Y6N4PrHYIa0SsLpTbdBkVgvAHSsZ8mh9NklsbUqoAaIBwQp5OTa20 CeSYYG+Z8cqecoufLcOp2Z1QqpWTlL9CCPsp/hotpzADkAm4/Ybjt23Z1X4A+pIIcuMI geJPjwlTmMCNdYtsyLK088j/wTFXkCA+/6OZqRSQgt7VtDG7uuYvXIy0C06Rqqdgk+9g D2ryWQgQjnJ7WSdFNrLKofVjLWn3K/qB+ODr9G/09BbMGD9hzpRgEexDotCW3+YpS0nh 0jdk0Tk82VI185gExzLWFkPGBh1fS6DrmJMxuNZYwv90GtWFS4BvpVJJ/i9Xs7t01+y8 C2Zw== X-Gm-Message-State: ACrzQf2Hm7EgWRPt8xZaTU4Q+oAc3EA9oL+6T8ycxFEpcnv5KKlykxTi sS9yu2Bxv2VvhvYJPwgAOIM= X-Google-Smtp-Source: AMsMyM6lvtVACNsxfedRoHg8QL0eEzDkDojvANf66ylQAV3UUIxgYAO1A8wxZ5nQ+3LoludTuiqErw== X-Received: by 2002:a17:902:8e84:b0:178:71f2:113c with SMTP id bg4-20020a1709028e8400b0017871f2113cmr30684765plb.79.1667493631028; Thu, 03 Nov 2022 09:40:31 -0700 (PDT) Received: from smtpclient.apple ([66.170.99.95]) by smtp.gmail.com with ESMTPSA id u62-20020a627941000000b0056cc99862f8sm998472pfc.92.2022.11.03.09.40.29 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Nov 2022 09:40:30 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.1\)) Subject: Re: [RFC] Kernel Support of Memory Error Detection. From: Nadav Amit In-Reply-To: Date: Thu, 3 Nov 2022 09:40:28 -0700 Cc: Jiaqi Yan , "naoya.horiguchi@nec.com" , "dave.hansen@linux.intel.com" , David Hildenbrand , "Aktas, Erdem" , "pgonda@google.com" , "rientjes@google.com" , "Hsiao, Duen-wen" , "Vilas.Sridharan@amd.com" , "Malvestuto, Mike" , "gthelen@google.com" , "linux-mm@kvack.org" , "jthoughton@google.com" Content-Transfer-Encoding: quoted-printable Message-Id: <7E670362-C29E-4626-B546-26530D54F937@gmail.com> References: <20221103155029.2451105-1-jiaqiyan@google.com> To: "Luck, Tony" X-Mailer: Apple Mail (2.3696.120.41.1.1) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1667493632; 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=zZXbeTNxYGfebgmrJLDuDejr3HgrFhPDQnfu9126FIM=; b=0DmI3dN+Jbcu6kZO/22bf8xVm5n3p3h4+ziisgvjgl4wgUQJyiKd2HyFkaZw6TYJlC/VLr 8fa4CbsBaA7dCmpH5y14hBV5gJYQz5P0DEgQkXHBicGKSXXD97W/bA8DRFtJZTg0r+ySi0 L5DxvMO6L4YSAUMA+3ylo2EQVSgW458= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=GjBeokYZ; spf=pass (imf05.hostedemail.com: domain of nadav.amit@gmail.com designates 209.85.214.175 as permitted sender) smtp.mailfrom=nadav.amit@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1667493632; a=rsa-sha256; cv=none; b=KunTDbQiCo3f5/EHlqIcjzjbjMx8+XM3YCmtZEWZKNa0oUMqUOvbJcdZnn2g7Wr/kiI+I8 /Aklo6IJq9DpoCCP03JpuveLo6uCeNubXVAT7qBliJC5PDmRvKxyHXxTWa3KLS/+6Pzdhr FrqqkOro9Wo2+SFiZdX6X3Qmwd8UbS0= X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 400F8100002 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=GjBeokYZ; spf=pass (imf05.hostedemail.com: domain of nadav.amit@gmail.com designates 209.85.214.175 as permitted sender) smtp.mailfrom=nadav.amit@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: xkjsf8qzk6fxantkje1f34z1ps8c5meg X-HE-Tag: 1667493632-362248 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: On Nov 3, 2022, at 9:27 AM, Luck, Tony wrote: >> - HPS usually doesn=E2=80=99t consume CPU cores but does consume = memory >> controller cycles and memory bandwidth. SW consumes both CPU cycles >> and memory bandwidth, but is only a problem if administrators opt = into >> the scanning after weighing the cost benefit. >=20 > Maybe there is a middle ground on platforms that support some s/w = programmable > DMA engine that can detect memory errors in a way that doesn't signal = a > fatal system error. Your s/w scanner can direct that DMA engine to = read from > the regions of memory that you want to scan, at a frequency that is = compatible > with your system load requirements and risk assessments. >=20 > If your idea gets traction, maybe structure the code so that it can = either use > a CPU core scan a block of memory, or pass requests to a platform = driver that can > use a DMA engine to perform the scan. That=E2=80=99s exactly what I was about the write. :) Quickassist can be perfect for that. The IOMMU can be programmed to make = the memory uncachable.