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[209.132.183.28]) by mx.google.com with ESMTPS id t80si867278qka.200.2019.03.08.11.13.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 08 Mar 2019 11:13:51 -0800 (PST) Received-SPF: pass (google.com: domain of aarcange@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 aarcange@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=aarcange@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 E189D318A5EA; Fri, 8 Mar 2019 19:13:50 +0000 (UTC) Received: from sky.random (ovpn-121-1.rdu2.redhat.com [10.10.121.1]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9EA091001DD4; Fri, 8 Mar 2019 19:13:46 +0000 (UTC) Date: Fri, 8 Mar 2019 14:13:45 -0500 From: Andrea Arcangeli To: Jason Wang Cc: Jerome Glisse , "Michael S. Tsirkin" , 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 Subject: Re: [RFC PATCH V2 5/5] vhost: access vq metadata through kernel virtual address Message-ID: <20190308191345.GB26923@redhat.com> References: <1551856692-3384-1-git-send-email-jasowang@redhat.com> <1551856692-3384-6-git-send-email-jasowang@redhat.com> <20190307103503-mutt-send-email-mst@kernel.org> <20190307124700-mutt-send-email-mst@kernel.org> <20190307191720.GF3835@redhat.com> <43408100-84d9-a359-3e78-dc65fb7b0ad1@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43408100-84d9-a359-3e78-dc65fb7b0ad1@redhat.com> User-Agent: Mutt/1.11.3 (2019-02-01) 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 [10.5.110.41]); Fri, 08 Mar 2019 19:13:50 +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 Fri, Mar 08, 2019 at 04:58:44PM +0800, Jason Wang wrote: > Can I simply can set_page_dirty() before vunmap() in the mmu notifier > callback, or is there any reason that it must be called within vumap()? I also don't see any problem in doing it before vunmap. As far as the mmu notifier and set_page_dirty is concerned vunmap is just put_page. It's just slower and potentially unnecessary.