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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 6D16FC2BA19 for ; Tue, 21 Apr 2020 09:22:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4D2D420CC7 for ; Tue, 21 Apr 2020 09:22:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728162AbgDUJWh (ORCPT ); Tue, 21 Apr 2020 05:22:37 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:47543 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725920AbgDUJWg (ORCPT ); Tue, 21 Apr 2020 05:22:36 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R461e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04397;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=11;SR=0;TI=SMTPD_---0TwDn81a_1587460953; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0TwDn81a_1587460953) by smtp.aliyun-inc.com(127.0.0.1); Tue, 21 Apr 2020 17:22:34 +0800 Subject: Re: [PATCH 16/18] mm: memcontrol: charge swapin pages on instantiation To: Johannes Weiner , Joonsoo Kim Cc: Shakeel Butt , Hugh Dickins , Michal Hocko , "Kirill A. Shutemov" , Roman Gushchin , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com References: <20200420221126.341272-1-hannes@cmpxchg.org> <20200420221126.341272-17-hannes@cmpxchg.org> From: Alex Shi Message-ID: <6f03ed4e-f917-2ccc-26c0-c438c84d3d97@linux.alibaba.com> Date: Tue, 21 Apr 2020 17:21:26 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200420221126.341272-17-hannes@cmpxchg.org> Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ÔÚ 2020/4/21 ÉÏÎç6:11, Johannes Weiner дµÀ: > Right now, users that are otherwise memory controlled can easily > escape their containment and allocate significant amounts of memory > that they're not being charged for. That's because swap readahead > pages are not being charged until somebody actually faults them into > their page table. This can be exploited with MADV_WILLNEED, which > triggers arbitrary readahead allocations without charging the pages. > > There are additional problems with the delayed charging of swap pages: > > 1. To implement refault/workingset detection for anonymous pages, we > need to have a target LRU available at swapin time, but the LRU is > not determinable until the page has been charged. > > 2. To implement per-cgroup LRU locking, we need page->mem_cgroup to be > stable when the page is isolated from the LRU; otherwise, the locks > change under us. But swapcache gets charged after it's already on > the LRU, and even if we cannot isolate it ourselves (since charging > is not exactly optional). > > The previous patch ensured we always maintain cgroup ownership records > for swap pages. This patch moves the swapcache charging point from the > fault handler to swapin time to fix all of the above problems. > > Signed-off-by: Johannes Weiner Reviewed-by: Alex Shi From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: Re: [PATCH 16/18] mm: memcontrol: charge swapin pages on instantiation Date: Tue, 21 Apr 2020 17:21:26 +0800 Message-ID: <6f03ed4e-f917-2ccc-26c0-c438c84d3d97@linux.alibaba.com> References: <20200420221126.341272-1-hannes@cmpxchg.org> <20200420221126.341272-17-hannes@cmpxchg.org> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20200420221126.341272-17-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="iso-8859-1" To: Johannes Weiner , Joonsoo Kim Cc: Shakeel Butt , Hugh Dickins , Michal Hocko , "Kirill A. Shutemov" , Roman Gushchin , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-team-b10kYP2dOMg@public.gmane.org =D4=DA 2020/4/21 =C9=CF=CE=E76:11, Johannes Weiner =D0=B4=B5=C0: > Right now, users that are otherwise memory controlled can easily > escape their containment and allocate significant amounts of memory > that they're not being charged for. That's because swap readahead > pages are not being charged until somebody actually faults them into > their page table. This can be exploited with MADV_WILLNEED, which > triggers arbitrary readahead allocations without charging the pages. >=20 > There are additional problems with the delayed charging of swap pages: >=20 > 1. To implement refault/workingset detection for anonymous pages, we > need to have a target LRU available at swapin time, but the LRU is > not determinable until the page has been charged. >=20 > 2. To implement per-cgroup LRU locking, we need page->mem_cgroup to be > stable when the page is isolated from the LRU; otherwise, the locks > change under us. But swapcache gets charged after it's already on > the LRU, and even if we cannot isolate it ourselves (since charging > is not exactly optional). >=20 > The previous patch ensured we always maintain cgroup ownership records > for swap pages. This patch moves the swapcache charging point from the > fault handler to swapin time to fix all of the above problems. >=20 > Signed-off-by: Johannes Weiner Reviewed-by: Alex Shi