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=-12.9 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1, USER_IN_DEF_DKIM_WL 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 E8732CA9ECB for ; Thu, 31 Oct 2019 18:16:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1FE521734 for ; Thu, 31 Oct 2019 18:16:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ZZoSEWiu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729219AbfJaSQK (ORCPT ); Thu, 31 Oct 2019 14:16:10 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:39442 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729027AbfJaSQK (ORCPT ); Thu, 31 Oct 2019 14:16:10 -0400 Received: by mail-pl1-f196.google.com with SMTP id t12so3041958plo.6 for ; Thu, 31 Oct 2019 11:16:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=K2iXeP4n/LwziPu4ZI0OnTyPorZqTcS6twEPx1hqLdc=; b=ZZoSEWiuBiik9RngUZeM0aAoWI9AFCUNVgIOH02T+Zipkev3DGDSdgR04ugiyl+Xjh /w/R1/t8Uf/OyFOuZzdsZ2o0wguO61GJAUdq9KcvaQXB30WaHfBQBqNJtj3frvwjpZGW DNrZviL6OPWqo7YTYYINjXLQVdc1qRWQJyxExYmhi2EXcQtdi13mFBlEgJdEX/C+bVUu EEgHZexKJwTbTO/99HqM5GuZEcJKn8HmquvFjGXsrBjlRhISx5oBspIuE50ZE8KWy6EF oxMnUfuJaJlW6Lu2eCY3ofQ6ytmmH4E9Z/6EjUl3CigFKtL88U21b8Fdeb1wvNxAZTh3 2FBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=K2iXeP4n/LwziPu4ZI0OnTyPorZqTcS6twEPx1hqLdc=; b=Y4zB6suYSI/oaed4ENRnCAyf4jYW+RFOcGcyBaTEbIN49HTdo8DUBIs2LedI+6GfOz ealcXGS64cjulpK38Uk8YSrSPn5abuD6O7TRSk4S16xMf6Kv/JPB4bLQl4CEmCLBKf8e Or9UNWKDa7Le/iewSRjgLB0n4wnYxHtij/P7ohnzzZ0ziDJifxbZMhHE5rVMeB7b35Xg E28vHv0FnUkU+Fo5D9IIQjHBoYRW9SheR6MexzOJZ9VOW5fi9K3zVHqExgvBbMx5Bl7i sMIJp3O5Abs/3eduya5FK6yqRDwlrmsVKh6iyRirrZxGoT+EM/hC7J6fbEdnqW3CjHMS CXAg== X-Gm-Message-State: APjAAAUlALeSVQsVCI9jWpieROl3NR9Hba7vZ+j0LraADsPxT9vroKfL dWGeAJlvkK6EnlS2UKmSviW8SQ== X-Google-Smtp-Source: APXvYqyubcz1aeS43b5/oVJTOA+Lgv6A7pzeQRkjnlzDj+Vyrx5Aef3FMZd2GCIXWcCCPV3DgS/bEQ== X-Received: by 2002:a17:902:4a:: with SMTP id 68mr7864287pla.8.1572545769038; Thu, 31 Oct 2019 11:16:09 -0700 (PDT) Received: from [2620:15c:17:3:3a5:23a7:5e32:4598] ([2620:15c:17:3:3a5:23a7:5e32:4598]) by smtp.gmail.com with ESMTPSA id 74sm3620489pgb.62.2019.10.31.11.16.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 31 Oct 2019 11:16:08 -0700 (PDT) Date: Thu, 31 Oct 2019 11:16:07 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Roman Gushchin cc: linux-mm@kvack.org, Andrew Morton , Michal Hocko , Johannes Weiner , linux-kernel@vger.kernel.org, kernel-team@fb.com, Vladimir Davydov , Daniel Jordan Subject: Re: [PATCH v2] mm: slab: make page_cgroup_ino() to recognize non-compound slab pages properly In-Reply-To: <20191031012151.2722280-1-guro@fb.com> Message-ID: References: <20191031012151.2722280-1-guro@fb.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 30 Oct 2019, Roman Gushchin wrote: > page_cgroup_ino() doesn't return a valid memcg pointer for non-compound > slab pages, because it depends on PgHead AND PgSlab flags to be set > to determine the memory cgroup from the kmem_cache. > It's correct for compound pages, but not for generic small pages. Those > don't have PgHead set, so it ends up returning zero. > > Fix this by replacing the condition to PageSlab() && !PageTail(). > > Before this patch: > [root@localhost ~]# ./page-types -c /sys/fs/cgroup/user.slice/user-0.slice/user@0.service/ | grep slab > 0x0000000000000080 38 0 _______S___________________________________ slab > > After this patch: > [root@localhost ~]# ./page-types -c /sys/fs/cgroup/user.slice/user-0.slice/user@0.service/ | grep slab > 0x0000000000000080 147 0 _______S___________________________________ slab > > Fixes: 4d96ba353075 ("mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages") > Signed-off-by: Roman Gushchin > Reviewed-by: Shakeel Butt > Cc: Vladimir Davydov > Cc: Daniel Jordan Acked-by: David Rientjes