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 X-Spam-Level: X-Spam-Status: No, score=-7.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D08AFC43381 for ; Wed, 20 Feb 2019 23:58:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8A5162087B for ; Wed, 20 Feb 2019 23:58:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="dmqbfBMw" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8A5162087B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 246098E0049; Wed, 20 Feb 2019 18:58:54 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1F5548E0002; Wed, 20 Feb 2019 18:58:54 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0E4FA8E0049; Wed, 20 Feb 2019 18:58:54 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-yb1-f200.google.com (mail-yb1-f200.google.com [209.85.219.200]) by kanga.kvack.org (Postfix) with ESMTP id DBCDA8E0002 for ; Wed, 20 Feb 2019 18:58:53 -0500 (EST) Received: by mail-yb1-f200.google.com with SMTP id d9so13563195ybn.18 for ; Wed, 20 Feb 2019 15:58:53 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding:dkim-signature; bh=jP+wiat2XSsdStfjMflPAPZ0y6VSuTquKiZkpsPA0wk=; b=l/l+PMkBmVr/ZAscHm3Pg5bk2pN9+cTrkQCzp6RZ7xGlKXMMi28OZN7re2VfiWs+7/ zr6o10T2X1pWvj2/Pz+WEiDVsjZFTWuN35c/1VeKQXsTfu1wzm4wbQH/GLQbZud9M6FV dQxrJtzGc6lsFOvMNnf6rLoF9tWnr1Kt8ybXdFI6Cwnkaoq9TTUUJYaie650lcuyhqje ED2Jyl6DSpPh1YqLf3agqFdTCA+LjwFX3BhUYrjBZXJ/07RAafk5NaCuu8A1iOEfZxzK YlZVurKKqF29aSxDbMUmolL6f0fVp/GJHZiG9OGF7b37wIx3NsM3qcdH5i467AgiZSz0 Ju5A== X-Gm-Message-State: AHQUAuYaDqPtQzKVKyYF3h1C37mb1iCdyDep/QzDkQRqYgQEcvIxRie6 Q7HT0B41IE+BgrJy2qO1b/3ZzXvJF82QQoUJjq9t+bkvUinCJDVYiMK3fJxpcjnxRtizZxDtsE3 t1oF/lG82kQlmQXg1bsTBlhN7Cd+tfIQLlKZuSo7KVsMAgZqbLlbOZgrslyH8T6xupw== X-Received: by 2002:a25:73cc:: with SMTP id o195mr29751196ybc.310.1550707133635; Wed, 20 Feb 2019 15:58:53 -0800 (PST) X-Google-Smtp-Source: AHgI3IYWAHqeEToaeg7blZRZEQEWf0KQ+Ru94VJX3ZhO4Yy8ulBPr8UNoJKjCYFO2UYlJICpt9ei X-Received: by 2002:a25:73cc:: with SMTP id o195mr29751172ybc.310.1550707133077; Wed, 20 Feb 2019 15:58:53 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1550707133; cv=none; d=google.com; s=arc-20160816; b=FyPpBYFWjxnTPHm71NQO89cShzDnDm7Bv8w+4QrpLOzDbPfUbpAayn679GmVc6F/0E M607r+gnCJj8CYHeRKzLewrEVyJc/pYfdyUaUNs96xulOESFdweCoYDwVpjaMlY+21Ta OkPsloSMPIU2BtsbUihe1t80S3rVxWHjoHGy0ac3SvNLGSaARUF8nzN8BI+OOmQyPw5R 0wiP+0zpwGRAa1znmTnnKjlxP+xGD3YkcJPPSzz47iFYcQBMWGvDnSMO4ZmUx5cuIph4 SJ8DnDCwECRcJ1dNJruwKncl8Vh6qcYoyYCDC69I6nEVeysmcl4VX6tUWNyM34DVMQmm ohQg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=dkim-signature:content-transfer-encoding:content-language :in-reply-to:mime-version:user-agent:date:message-id:from:references :cc:to:subject; bh=jP+wiat2XSsdStfjMflPAPZ0y6VSuTquKiZkpsPA0wk=; b=RbfgWWvVlbTjyi8GC6b9QQAM/21lQz4cKJ16SbbqKpHL+XxNwqlM0B7V3mftaWXU5J 7F7j+XEURslZMkX8eRipm6UhMk/BHaSBAbiwqdMCovukVgRthCW95Y2M/11x5JfLrmNR I3w543alsS7N0ci+IB+Nddhub69Ebv/k0wkJ0B5P6xyko4LGsK6pUmyjRgGSbJtLdo5N eJqQ4C8cFiSpntLtDpVg7JrRMtf7h0TyNavXur2oBIRI/PUgqg2ahY5vbMTGs5Ef2+rU XOx9UtVvViQ3o/viH8UT4sVQ/QBRGUDA9kkKJH2Gl/giz2K4GDW+Oi6rPZ+XYm9mmFI8 8dSw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=dmqbfBMw; spf=pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.65 as permitted sender) smtp.mailfrom=jhubbard@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqemgate16.nvidia.com (hqemgate16.nvidia.com. [216.228.121.65]) by mx.google.com with ESMTPS id x76si6541891ybg.490.2019.02.20.15.58.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 20 Feb 2019 15:58:53 -0800 (PST) Received-SPF: pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.65 as permitted sender) client-ip=216.228.121.65; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=dmqbfBMw; spf=pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.65 as permitted sender) smtp.mailfrom=jhubbard@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate16.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 20 Feb 2019 15:58:58 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Wed, 20 Feb 2019 15:58:52 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Wed, 20 Feb 2019 15:58:52 -0800 Received: from [10.2.169.124] (172.20.13.39) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Wed, 20 Feb 2019 23:58:51 +0000 Subject: Re: [PATCH 02/10] mm/hmm: do not erase snapshot when a range is invalidated To: , CC: , Andrew Morton , Ralph Campbell References: <20190129165428.3931-1-jglisse@redhat.com> <20190129165428.3931-3-jglisse@redhat.com> From: John Hubbard Message-ID: Date: Wed, 20 Feb 2019 15:58:40 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <20190129165428.3931-3-jglisse@redhat.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL101.nvidia.com (172.20.187.10) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1550707138; bh=jP+wiat2XSsdStfjMflPAPZ0y6VSuTquKiZkpsPA0wk=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=dmqbfBMwvjaiDm4+ShTJ/pUB6RmCQ/z4LdRkHsxmLjQ13SeSj75L5H16XUZNvEgI5 KEuJ9clung0YkN8Juhf52xYrG7rcjUYdiVcxmOWAgxJXFACrSuhAy3Dh+RZRJAWjGl v5f2fKZFcdS75UivGyHgoA0Agrlufs+52Go8uJmzob84TdtuO7FpQIoizsu33g8cET EAAQoIID1RfvmJ6mYYiR/7gFk0CgqV+Ytoxt5dYrpbJtgk1CTKd68Z6eSYBuHR0DzG 5+b6jYldNox+246RO7rJN2dpYw6rxa07YhZVJ0rWzaR8cMYihE2hggXo2yOumsXtc2 QhGMT+ce258jA== 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 1/29/19 8:54 AM, jglisse@redhat.com wrote: > From: J=C3=A9r=C3=B4me Glisse >=20 > Users of HMM might be using the snapshot information to do > preparatory step like dma mapping pages to a device before > checking for invalidation through hmm_vma_range_done() so > do not erase that information and assume users will do the > right thing. >=20 > Signed-off-by: J=C3=A9r=C3=B4me Glisse > Cc: Andrew Morton > Cc: Ralph Campbell > Cc: John Hubbard > --- > mm/hmm.c | 6 ------ > 1 file changed, 6 deletions(-) >=20 > diff --git a/mm/hmm.c b/mm/hmm.c > index b9f384ea15e9..74d69812d6be 100644 > --- a/mm/hmm.c > +++ b/mm/hmm.c > @@ -170,16 +170,10 @@ static int hmm_invalidate_range(struct hmm *hmm, bo= ol device, > =20 > spin_lock(&hmm->lock); > list_for_each_entry(range, &hmm->ranges, list) { > - unsigned long addr, idx, npages; > - > if (update->end < range->start || update->start >=3D range->end) > continue; > =20 > range->valid =3D false; > - addr =3D max(update->start, range->start); > - idx =3D (addr - range->start) >> PAGE_SHIFT; > - npages =3D (min(range->end, update->end) - addr) >> PAGE_SHIFT; > - memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages); > } > spin_unlock(&hmm->lock); > =20 >=20 Seems harmless to me. I really cannot see how this could cause a problem, so you can add: Reviewed-by: John Hubbard thanks, --=20 John Hubbard NVIDIA