From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752238AbdGaMdg (ORCPT ); Mon, 31 Jul 2017 08:33:36 -0400 Received: from mga01.intel.com ([192.55.52.88]:13358 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbdGaMdf (ORCPT ); Mon, 31 Jul 2017 08:33:35 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,442,1496127600"; d="scan'208";a="999121779" Message-ID: <597F2439.5070309@intel.com> Date: Mon, 31 Jul 2017 20:36:09 +0800 From: Wei Wang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: "linux-kernel@vger.kernel.org" , "qemu-devel@nongnu.org" , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "linux-mm@kvack.org" , "david@redhat.com" , "cornelia.huck@de.ibm.com" , "akpm@linux-foundation.org" , "mgorman@techsingularity.net" , "aarcange@redhat.com" , "amit.shah@redhat.com" , "pbonzini@redhat.com" , "liliang.opensource@gmail.com" , "virtio-dev@lists.oasis-open.org" , "yang.zhang.wz@gmail.com" , "quan.xu@aliyun.com" Subject: Re: [PATCH v12 5/8] virtio-balloon: VIRTIO_BALLOON_F_SG References: <59686EEB.8080805@intel.com> <20170723044036-mutt-send-email-mst@kernel.org> <59781119.8010200@intel.com> <20170726155856-mutt-send-email-mst@kernel.org> <597954E3.2070801@intel.com> <20170729020231-mutt-send-email-mst@kernel.org> <597C83CC.7060702@intel.com> <20170730043922-mutt-send-email-mst@kernel.org> <286AC319A985734F985F78AFA26841F739288D85@shsmsx102.ccr.corp.intel.com> <20170730191735-mutt-send-email-mst@kernel.org> <20170730191911-mutt-send-email-mst@kernel.org> In-Reply-To: <20170730191911-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/31/2017 12:20 AM, Michael S. Tsirkin wrote: > On Sun, Jul 30, 2017 at 07:18:33PM +0300, Michael S. Tsirkin wrote: >> On Sun, Jul 30, 2017 at 05:59:17AM +0000, Wang, Wei W wrote: >> That's a hypervisor implementation detail. From guest point of view, >> discarding contents can not be distinguished from writing old contents. >> > Besides, ignoring the free page tricks, consider regular ballooning. > We map page with DONTNEED then back with WILLNEED. Result is > getting a zero page. So at least one of deflate/inflate should be input. > I'd say both for symmetry. > OK, I see the point. Thanks. Best, Wei