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 C9F3AC4321E for ; Mon, 5 Dec 2022 14:22:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231929AbiLEOWM (ORCPT ); Mon, 5 Dec 2022 09:22:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34090 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231848AbiLEOVr (ORCPT ); Mon, 5 Dec 2022 09:21:47 -0500 Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0C7C1A226 for ; Mon, 5 Dec 2022 06:21:40 -0800 (PST) Received: by mail-ed1-x535.google.com with SMTP id c17so7427196edj.13 for ; Mon, 05 Dec 2022 06:21:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20210112.gappssmtp.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=tObwGL/MMlN8TFc4loLjh6BEZOWq+dlz3cmU/K+yIJU=; b=U6H6h2KUZy6VCNfkxfLiN6T83KRyTFEGLS0dRWLukW4LvZIpidZt9usPMNKcc1MXAa N5G6Ikftb3O5mNI1EMqxWBWKYXIMpBOeyKB7k/BGFsINBVuuTCacGM4k2elEz6XfwBj+ SJ9GZb34xcJw6CXCNReIfUMgpMGZUYcw8GE/+XfVwseG/P8UUN0RBdXdMXI1tJWzg8p6 w+TAXqT3YAM++g2ny/qmau2TNawLxsG9nkWT00SwxbljMQnxbfWmDcxVaHBLYfQXfBcL jC4O9sRlwJxqJnERlBYFz0sWCMzBZCe8ApbOgEc6itbSXdXoxJ0HT8shH5UBI96Bmqz+ HyKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=tObwGL/MMlN8TFc4loLjh6BEZOWq+dlz3cmU/K+yIJU=; b=WVSi5vBVhAIL2dhJxo+7vl+blkAkkncn6vVizjTJvWSUowJQ9/pxa5dT0aQphkWplI VHAiA2V4hM8av7TZPM/m+ZgraGIk+J8mVogf/7agv8GBgZHrUgkXU04UsgKPPiwUI68X yb9M/o8Ogd6iInH5YVbxS9foAwZ2lJ1D49Y4Pjp93NBlta4pznclSU4dUiXTEtz6D1+y hfGQ9BVM4foHRqYTv6Rbf3qV5tnRuPbK0Xglfbw6cpwRdmLipEvXomg122SSeK1lXFDC QrHZvmBnxmqw/HvjV6Rw9K+nL4SRXH44ofBlKirpfirTFxbXetDHJ+0+iJeUe8zZND3N hbUg== X-Gm-Message-State: ANoB5pktNDYQ2lw5LYKFfc51hhmz1jTOx5/ATGfaEddPiTjGwMY0lrod eam7YLOIe9Y4313/S2C6rKQHug== X-Google-Smtp-Source: AA0mqf4VoiAU0KpEZaoGn5PrdL7QEenwhLzzYkXw99I0TKH42IlhUBWCvbyH/cPDb9Qr8aHSXoT9Mg== X-Received: by 2002:a05:6402:5290:b0:461:af68:9bcd with SMTP id en16-20020a056402529000b00461af689bcdmr58605297edb.67.1670250099275; Mon, 05 Dec 2022 06:21:39 -0800 (PST) Received: from localhost ([2a02:8070:6387:ab20:15aa:3c87:c206:d15e]) by smtp.gmail.com with ESMTPSA id bm14-20020a0564020b0e00b0046bf4935323sm3888099edb.30.2022.12.05.06.21.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 05 Dec 2022 06:21:38 -0800 (PST) Date: Mon, 5 Dec 2022 09:21:37 -0500 From: Johannes Weiner To: Hugh Dickins Cc: Andrew Morton , Shakeel Butt , Michal Hocko , Roman Gushchin , Yu Zhao , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm: memcg: fix swapcached stat accounting Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Dec 04, 2022 at 05:01:03PM -0800, Hugh Dickins wrote: > I'd been worried by high "swapcached" counts in memcg OOM reports, > thought we had a problem freeing swapcache, but it was just the > accounting that was wrong. > > Two issues: > > 1. When __remove_mapping() removes swapcache, __delete_from_swap_cache() > relies on memcg_data for the right counts to be updated; but that had > already been reset by mem_cgroup_swapout(). Swap those calls around - > mem_cgroup_swapout() does not require the swapcached flag to be set. > > 6.1 commit ac35a4902374 ("mm: multi-gen LRU: minimal implementation") > already made a similar swap for workingset_eviction(), but not for this. > > 2. memcg's "swapcached" count was added for memcg v2 stats, but displayed > on OOM even for memcg v1: so mem_cgroup_move_account() ought to move it. > > Fixes: b6038942480e ("mm: memcg: add swapcache stat for memcg v2") > Signed-off-by: Hugh Dickins Acked-by: Johannes Weiner