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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 9B4C3C33CA1 for ; Wed, 5 Feb 2020 09:19:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6322021741 for ; Wed, 5 Feb 2020 09:19:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6322021741 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E76B86B0088; Wed, 5 Feb 2020 04:19:14 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E08F56B0089; Wed, 5 Feb 2020 04:19:14 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CEF366B008A; Wed, 5 Feb 2020 04:19:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0141.hostedemail.com [216.40.44.141]) by kanga.kvack.org (Postfix) with ESMTP id B50F86B0088 for ; Wed, 5 Feb 2020 04:19:14 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 57213181AEF09 for ; Wed, 5 Feb 2020 09:19:14 +0000 (UTC) X-FDA: 76455524628.09.birth04_3352674acda25 X-HE-Tag: birth04_3352674acda25 X-Filterd-Recvd-Size: 5269 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Wed, 5 Feb 2020 09:19:12 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2020 01:19:11 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,405,1574150400"; d="scan'208";a="220039462" Received: from fmsmsx105.amr.corp.intel.com ([10.18.124.203]) by orsmga007.jf.intel.com with ESMTP; 05 Feb 2020 01:19:10 -0800 Received: from fmsmsx601.amr.corp.intel.com (10.18.126.81) by FMSMSX105.amr.corp.intel.com (10.18.124.203) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 5 Feb 2020 01:19:10 -0800 Received: from fmsmsx601.amr.corp.intel.com (10.18.126.81) by fmsmsx601.amr.corp.intel.com (10.18.126.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Wed, 5 Feb 2020 01:19:09 -0800 Received: from shsmsx103.ccr.corp.intel.com (10.239.4.69) by fmsmsx601.amr.corp.intel.com (10.18.126.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.1713.5 via Frontend Transport; Wed, 5 Feb 2020 01:19:09 -0800 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.126]) by SHSMSX103.ccr.corp.intel.com ([169.254.4.196]) with mapi id 14.03.0439.000; Wed, 5 Feb 2020 17:19:08 +0800 From: "Wang, Wei W" To: David Hildenbrand , "Michael S. Tsirkin" CC: Nadav Amit , Alexander Duyck , Tyler Sanderson , "virtualization@lists.linux-foundation.org" , David Rientjes , "linux-mm@kvack.org" , "Michal Hocko" Subject: RE: Balloon pressuring page cache Thread-Topic: Balloon pressuring page cache Thread-Index: AQHV1jovoZrFI2PKjUOgo5GIAcuyoKgA6/YAgACRPICAAUzXAIAAibNg///JVwCABdc9AIAANGSAgAAETACAAGklgIAAo12AgAABfACAAGGxgIABj+gw//+atoCAAIwXoP//fmaAABDM2dD//3whAP//eIgw Date: Wed, 5 Feb 2020 09:19:07 +0000 Message-ID: <286AC319A985734F985F78AFA26841F73E41F3DE@shsmsx102.ccr.corp.intel.com> References: <91270a68-ff48-88b0-219c-69801f0c252f@redhat.com> <75d4594f-0864-5172-a0f8-f97affedb366@redhat.com> <286AC319A985734F985F78AFA26841F73E3F8A02@shsmsx102.ccr.corp.intel.com> <20200203080520-mutt-send-email-mst@kernel.org> <5ac131de8e3b7fc1fafd05a61feb5f6889aeb917.camel@linux.intel.com> <539B606A-A0CA-4AA4-B99A-759C874A1EF8@vmware.com> <20200204033657-mutt-send-email-mst@kernel.org> <286AC319A985734F985F78AFA26841F73E41F0F0@shsmsx102.ccr.corp.intel.com> <1eff30a0-a38a-cd45-2fc1-80cfd0bf5f04@redhat.com> <286AC319A985734F985F78AFA26841F73E41F306@shsmsx102.ccr.corp.intel.com> <2b388a78-79cd-f99a-6f87-6446dcb4b819@redhat.com> <286AC319A985734F985F78AFA26841F73E41F367@shsmsx102.ccr.corp.intel.com> <605bef3e-373f-f39a-4849-930326564b5b@redhat.com> In-Reply-To: <605bef3e-373f-f39a-4849-930326564b5b@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-version: 11.2.0.6 dlp-reaction: no-action x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 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 Wednesday, February 5, 2020 5:06 PM, David Hildenbrand wrote: >=20 > No, that does not answer my question. Because then, obviously the guest > can't do any hinting in the last round. I think I am missing something > important :) No problem, probably need more details here: QEMU has a dirty bitmap which indicates all the dirty pages from the previo= us round. KVM has a dirty bitmap which records what pages are modified in this round. When a new round starts, QEMU syncs the bitmap from KVM (this round always sends the pages dirtied from the previous round). > 1. Guest allocates a page and sends it to the host. > 2. Shrinker gets active and releases that page again. > 3. Some user in the guest allocates and modifies that page. The dirty bit= is > set in the hypervisor. The bit will be set in KVM's bitmap, and will be synced to QEMU's bitmap wh= en the next round starts. > 4. The host processes the request and clears the bit in the dirty bitmap. This clears the bit from the QEMU bitmap, and this page will not be sent in= this round. > 5. The guest is stopped and the last set of dirty pages is migrated. The > modified page is not being migrated (because not marked dirty). When QEMU start the last round, it first syncs the bitmap from KVM, which i= ncludes the one set in step 3. Then the modified page gets sent. Best, Wei