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[209.132.183.28]) by mx.google.com with ESMTPS id b22si2046164qvb.187.2019.03.06.18.46.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 Mar 2019 18:46:08 -0800 (PST) Received-SPF: pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of jasowang@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=jasowang@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 65AF7C05090A; Thu, 7 Mar 2019 02:46:07 +0000 (UTC) Received: from [10.72.12.83] (ovpn-12-83.pek2.redhat.com [10.72.12.83]) by smtp.corp.redhat.com (Postfix) with ESMTP id A0A7C1001DD9; Thu, 7 Mar 2019 02:45:59 +0000 (UTC) Subject: Re: [RFC PATCH V2 5/5] vhost: access vq metadata through kernel virtual address To: "Michael S. Tsirkin" Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, peterx@redhat.com, linux-mm@kvack.org, aarcange@redhat.com References: <1551856692-3384-1-git-send-email-jasowang@redhat.com> <1551856692-3384-6-git-send-email-jasowang@redhat.com> <20190306092837-mutt-send-email-mst@kernel.org> From: Jason Wang Message-ID: <15105894-4ec1-1ed0-1976-7b68ed9eeeda@redhat.com> Date: Thu, 7 Mar 2019 10:45:57 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190306092837-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 07 Mar 2019 02:46:07 +0000 (UTC) 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 2019/3/7 上午12:31, Michael S. Tsirkin wrote: >> +static void vhost_set_vmap_dirty(struct vhost_vmap *used) >> +{ >> + int i; >> + >> + for (i = 0; i < used->npages; i++) >> + set_page_dirty_lock(used->pages[i]); > This seems to rely on page lock to mark page dirty. > > Could it happen that page writeback will check the > page, find it clean, and then you mark it dirty and then > invalidate callback is called? > > Yes. But does this break anything? The page is still there, we just remove a kernel mapping to it. Thanks