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 7189CC33CA1 for ; Wed, 5 Feb 2020 08:51:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3E7002085B for ; Wed, 5 Feb 2020 08:51:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E7002085B 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 C69E16B0072; Wed, 5 Feb 2020 03:51:02 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BF24C6B0073; Wed, 5 Feb 2020 03:51:02 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ABC116B0074; Wed, 5 Feb 2020 03:51:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0024.hostedemail.com [216.40.44.24]) by kanga.kvack.org (Postfix) with ESMTP id 90E7E6B0072 for ; Wed, 5 Feb 2020 03:51:02 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3E8594DBF for ; Wed, 5 Feb 2020 08:51:02 +0000 (UTC) X-FDA: 76455453564.30.knee36_603caea21ab4e X-HE-Tag: knee36_603caea21ab4e X-Filterd-Recvd-Size: 4023 Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by imf47.hostedemail.com (Postfix) with ESMTP for ; Wed, 5 Feb 2020 08:51:01 +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 orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2020 00:50:59 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,405,1574150400"; d="scan'208";a="220032713" Received: from fmsmsx107.amr.corp.intel.com ([10.18.124.205]) by orsmga007.jf.intel.com with ESMTP; 05 Feb 2020 00:50:59 -0800 Received: from fmsmsx126.amr.corp.intel.com (10.18.125.43) by fmsmsx107.amr.corp.intel.com (10.18.124.205) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 5 Feb 2020 00:50:59 -0800 Received: from shsmsx152.ccr.corp.intel.com (10.239.6.52) by FMSMSX126.amr.corp.intel.com (10.18.125.43) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 5 Feb 2020 00:50:58 -0800 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.126]) by SHSMSX152.ccr.corp.intel.com ([169.254.6.76]) with mapi id 14.03.0439.000; Wed, 5 Feb 2020 16:50:56 +0800 From: "Wang, Wei W" To: "Michael S. Tsirkin" CC: David Hildenbrand , 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///JVwCABdc9AIAANGSAgAAETACAAGklgIAAo12AgAABfACAAGGxgIAAJx2AgAFxBnD//33eAIAAiZEA Date: Wed, 5 Feb 2020 08:50:55 +0000 Message-ID: <286AC319A985734F985F78AFA26841F73E41F2D9@shsmsx102.ccr.corp.intel.com> References: <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> <20200204114336-mutt-send-email-mst@kernel.org> <286AC319A985734F985F78AFA26841F73E41F10F@shsmsx102.ccr.corp.intel.com> <20200205015911-mutt-send-email-mst@kernel.org> In-Reply-To: <20200205015911-mutt-send-email-mst@kernel.org> 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 3:05 PM, Michael S. Tsirkin wrote: >=20 > Well if we did the hint would be reliable, allowing host to immediately d= rop > any pages it gets in the hint.=20 "drop", you mean host to unmap the page from guest? I think that's not allo= wed for hints. > Originally I wanted to speed up hinting by never > waiting for host, but that does not seem to be what was > implemented: the only place we don't wait is the shrinker Didn't get this one. For FREE_PAGE_HINT, the hints are always sent to host = without an ack from host about whether it has read the hint or not. (please see get= _free_page_and_send) > and it seems a > waste that we introduced complexity to host without getting any real > benefit out of it. >=20 > VIRTIO_BALLOON_F_MUST_TELL_HOST doesn't really apply to hinting right > now,=20 There is no need I think, as host isn't allowed to use or unmap the hint pa= ge. Best, Wei