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=-2.5 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 91CDBC5AE59 for ; Tue, 10 Sep 2019 18:00:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 64DC92171F for ; Tue, 10 Sep 2019 18:00:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 64DC92171F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 12B506B0006; Tue, 10 Sep 2019 14:00:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0DCC16B0007; Tue, 10 Sep 2019 14:00:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EC02E6B0008; Tue, 10 Sep 2019 14:00:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0110.hostedemail.com [216.40.44.110]) by kanga.kvack.org (Postfix) with ESMTP id CD6316B0006 for ; Tue, 10 Sep 2019 14:00:30 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 318B075B0 for ; Tue, 10 Sep 2019 18:00:30 +0000 (UTC) X-FDA: 75919775820.20.rice58_3e8c5fc3ff760 X-HE-Tag: rice58_3e8c5fc3ff760 X-Filterd-Recvd-Size: 3046 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Tue, 10 Sep 2019 18:00:29 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 0FCC7AF8D; Tue, 10 Sep 2019 18:00:28 +0000 (UTC) Date: Tue, 10 Sep 2019 20:00:26 +0200 From: Michal Hocko To: Alexander Duyck Cc: virtio-dev@lists.oasis-open.org, kvm list , "Michael S. Tsirkin" , Catalin Marinas , David Hildenbrand , Dave Hansen , LKML , Matthew Wilcox , linux-mm , Andrew Morton , will@kernel.org, linux-arm-kernel@lists.infradead.org, Oscar Salvador , Yang Zhang , Pankaj Gupta , Konrad Rzeszutek Wilk , Nitesh Narayan Lal , Rik van Riel , lcapitulino@redhat.com, "Wang, Wei W" , Andrea Arcangeli , ying.huang@intel.com, Paolo Bonzini , Dan Williams , Fengguang Wu , Alexander Duyck , "Kirill A. Shutemov" Subject: Re: [PATCH v9 0/8] stg mail -e --version=v9 \ Message-ID: <20190910180026.GE4023@dhcp22.suse.cz> References: <20190907172225.10910.34302.stgit@localhost.localdomain> <20190910124209.GY2063@dhcp22.suse.cz> <20190910144713.GF2063@dhcp22.suse.cz> <20190910175213.GD4023@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190910175213.GD4023@dhcp22.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) 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 Tue 10-09-19 19:52:13, Michal Hocko wrote: > On Tue 10-09-19 09:05:43, Alexander Duyck wrote: [...] > > All this is providing is just a report and it is optional if the > > hypervisor will act on it or not. If the hypervisor takes some sort of > > action on the page, then the expectation is that the hypervisor will > > use some sort of mechanism such as a page fault to discover when the > > page is used again. > > OK so the baloon driver is in charge of this metadata and the allocator > has to live with that. Isn't that a layer violation? Another thing that is not clear to me is how these marked pages are different from any other free pages. All of them are unused and you are losing your metadata as soon as the page gets allocated because the page changes its owner and the struct page belongs to it. -- Michal Hocko SUSE Labs