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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 E0941C64E69 for ; Sun, 22 Nov 2020 06:17:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A10CA208D5 for ; Sun, 22 Nov 2020 06:17:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Rf78JHKQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727323AbgKVGRO (ORCPT ); Sun, 22 Nov 2020 01:17:14 -0500 Received: from mail.kernel.org ([198.145.29.99]:55750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726957AbgKVGRN (ORCPT ); Sun, 22 Nov 2020 01:17:13 -0500 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B1C2620885; Sun, 22 Nov 2020 06:17:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1606025833; bh=V4UvNIFEgSB4f61jE+1hR5zA9b8uKcCSOXQu58krr8I=; h=Date:From:To:Subject:In-Reply-To:From; b=Rf78JHKQyePOpA8S+2V96F1CMPyZBTCz2A/4NZqlK7gNkRnyQIs38EwsdChQWn+SB VsBQh9BVKHYXwao14XKxG5TPaI2+HWmv+x1hBjSmxLdWrVZqnP3wKdOYbAE+cWgscn Vi8FB4XCckmT/1n30ir42vZRBDajcLbjvXNi/f+0= Date: Sat, 21 Nov 2020 22:17:12 -0800 From: Andrew Morton To: akpm@linux-foundation.org, chris@chrisdown.name, cl@linux.com, guro@fb.com, hannes@cmpxchg.org, iamjoonsoo.kim@lge.com, laoar.shao@gmail.com, linux-mm@kvack.org, mhocko@kernel.org, mm-commits@vger.kernel.org, penberg@kernel.org, rientjes@google.com, shakeelb@google.com, songmuchun@bytedance.com, stable@vger.kernel.org, torvalds@linux-foundation.org, vbabka@suse.cz, vdavydov.dev@gmail.com Subject: [patch 5/8] mm: memcg/slab: fix root memcg vmstats Message-ID: <20201122061712.pLjLif6pl%akpm@linux-foundation.org> In-Reply-To: <20201121221631.948ae4655e913a319d61700a@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Muchun Song Subject: mm: memcg/slab: fix root memcg vmstats If we reparent the slab objects to the root memcg, when we free the slab object, we need to update the per-memcg vmstats to keep it correct for the root memcg. Now this at least affects the vmstat of NR_KERNEL_STACK_KB for !CONFIG_VMAP_STACK when the thread stack size is smaller than the PAGE_SIZE. David said: "I assume that without this fix that the root memcg's vmstat would always be inflated if we reparented." Link: https://lkml.kernel.org/r/20201110031015.15715-1-songmuchun@bytedance.com Fixes: ec9f02384f60 ("mm: workingset: fix vmstat counters for shadow nodes") Signed-off-by: Muchun Song Acked-by: Roman Gushchin Reviewed-by: Shakeel Butt Acked-by: Johannes Weiner Acked-by: David Rientjes Cc: Michal Hocko Cc: Vladimir Davydov Cc: Christopher Lameter Cc: Pekka Enberg Cc: Joonsoo Kim Cc: Roman Gushchin Cc: Vlastimil Babka Cc: Yafang Shao Cc: Chris Down Cc: [5.3+] Signed-off-by: Andrew Morton --- mm/memcontrol.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/mm/memcontrol.c~mm-memcg-slab-fix-root-memcg-vmstats +++ a/mm/memcontrol.c @@ -867,8 +867,13 @@ void __mod_lruvec_slab_state(void *p, en rcu_read_lock(); memcg = mem_cgroup_from_obj(p); - /* Untracked pages have no memcg, no lruvec. Update only the node */ - if (!memcg || memcg == root_mem_cgroup) { + /* + * Untracked pages have no memcg, no lruvec. Update only the + * node. If we reparent the slab objects to the root memcg, + * when we free the slab object, we need to update the per-memcg + * vmstats to keep it correct for the root memcg. + */ + if (!memcg) { __mod_node_page_state(pgdat, idx, val); } else { lruvec = mem_cgroup_lruvec(memcg, pgdat); _