From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 89CCC6B05EF for ; Mon, 31 Jul 2017 08:33:30 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id d5so189747742pfg.3 for ; Mon, 31 Jul 2017 05:33:30 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id u25si16354886pgn.515.2017.07.31.05.33.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 31 Jul 2017 05:33:29 -0700 (PDT) Message-ID: <597F2439.5070309@intel.com> Date: Mon, 31 Jul 2017 20:36:09 +0800 From: Wei Wang MIME-Version: 1.0 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: owner-linux-mm@kvack.org List-ID: 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" 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org