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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00B05EE49A0 for ; Wed, 23 Aug 2023 13:12:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233146AbjHWNMt (ORCPT ); Wed, 23 Aug 2023 09:12:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41304 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231472AbjHWNMr (ORCPT ); Wed, 23 Aug 2023 09:12:47 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85B56E4E; Wed, 23 Aug 2023 06:12:43 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 467D820829; Wed, 23 Aug 2023 13:12:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1692796362; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Uz09CIFb4phUja5aPxrRB0e9q5bhxoa70nYLw9mLuHM=; b=jWTBefLrqe2p82kmhfsYvU/xVcAN6GLUbIIDYYcXdMJBReUCLsL7ElyotvzvcBfOpqzO/t 1hb3KK7+IQXveL1TfELQbWLV8euLDx/p1JGmt5VU/+RbtQbaVs3R/7z0gQg2JU8KqWMciz 7M+WaltLFLrP9qJqGJtUdr9uAG1bdzE= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 23EB713458; Wed, 23 Aug 2023 13:12:42 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id woQJBsoF5mSEZwAAMHmgww (envelope-from ); Wed, 23 Aug 2023 13:12:42 +0000 Date: Wed, 23 Aug 2023 15:12:41 +0200 From: Michal Hocko To: Liu Shixin Cc: Yosry Ahmed , Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , wangkefeng.wang@huawei.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2] mm: vmscan: reclaim anon pages if there are swapcache pages Message-ID: References: <20230822024901.2412520-1-liushixin2@huawei.com> <50c49baf-d04a-f1e3-0d0e-7bb8e22c3889@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <50c49baf-d04a-f1e3-0d0e-7bb8e22c3889@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 23-08-23 10:00:58, Liu Shixin wrote: > > > On 2023/8/23 0:35, Yosry Ahmed wrote: > > On Mon, Aug 21, 2023 at 6:54 PM Liu Shixin wrote: > >> When spaces of swap devices are exhausted, only file pages can be reclaimed. > >> But there are still some swapcache pages in anon lru list. This can lead > >> to a premature out-of-memory. > >> > >> This problem can be fixed by checking number of swapcache pages in > >> can_reclaim_anon_pages(). For memcg v2, there are swapcache stat that can > >> be used directly. For memcg v1, use total_swapcache_pages() instead, which > >> may not accurate but can solve the problem. > > Interesting find. I wonder if we really don't have any handling of > > this situation. > I have alreadly test this problem and can confirm that it is a real problem. > With 9MB swap space and 10MB mem_cgroup limit，when allocate 15MB memory, > there is a probability that OOM occurs. Could you be more specific about the test and the oom report? -- Michal Hocko SUSE Labs