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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no 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 C8261C43331 for ; Sun, 29 Mar 2020 02:17:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7F7A3206E6 for ; Sun, 29 Mar 2020 02:17:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pBoENYFu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7F7A3206E6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2FC038E0008; Sat, 28 Mar 2020 22:17:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 284CA8E0001; Sat, 28 Mar 2020 22:17:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 14F908E0008; Sat, 28 Mar 2020 22:17:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0054.hostedemail.com [216.40.44.54]) by kanga.kvack.org (Postfix) with ESMTP id EECC58E0001 for ; Sat, 28 Mar 2020 22:17:27 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 89458181AC9BF for ; Sun, 29 Mar 2020 02:17:27 +0000 (UTC) X-FDA: 76646788134.30.war57_23f8c7f56f408 X-HE-Tag: war57_23f8c7f56f408 X-Filterd-Recvd-Size: 7103 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Sun, 29 Mar 2020 02:17:27 +0000 (UTC) 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 1908A2071B; Sun, 29 Mar 2020 02:17:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585448246; bh=FezfGznBgp/9HKRaDPns+I3K5BAhmxa4z/RpP7e8FZI=; h=Date:From:To:Subject:In-Reply-To:From; b=pBoENYFu9lvl9S/bMWZDP7073TsBovoJANfvSNRwM983M8qu66nlKf8aaaNUCWzPA 2+J1CMoQFXl74R+I4sp85lbquWZxk+wphSNmnBBLEvfnjlwDRx11w5IHX3QNc5e+9/ G+IRbJ+J9xGdM4C5pSnBnbAWvBXbf8B914Raz5bc= Date: Sat, 28 Mar 2020 19:17:25 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bharata@linux.ibm.com, guro@fb.com, hannes@cmpxchg.org, linux-mm@kvack.org, mhocko@kernel.org, mm-commits@vger.kernel.org, shakeelb@google.com, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 4/5] mm: fork: fix kernel_stack memcg stats for various stack implementations Message-ID: <20200329021725.na3Cd6vpE%akpm@linux-foundation.org> In-Reply-To: <20200328191456.4fc0b9ca86780f26c122399e@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Roman Gushchin Subject: mm: fork: fix kernel_stack memcg stats for various stack implementations Depending on CONFIG_VMAP_STACK and the THREAD_SIZE / PAGE_SIZE ratio the space for task stacks can be allocated using __vmalloc_node_range(), alloc_pages_node() and kmem_cache_alloc_node(). In the first and the second cases page->mem_cgroup pointer is set, but in the third it's not: memcg membership of a slab page should be determined using the memcg_from_slab_page() function, which looks at page->slab_cache->memcg_params.memcg . In this case, using mod_memcg_page_state() (as in account_kernel_stack()) is incorrect: page->mem_cgroup pointer is NULL even for pages charged to a non-root memory cgroup. It can lead to kernel_stack per-memcg counters permanently showing 0 on some architectures (depending on the configuration). In order to fix it, let's introduce a mod_memcg_obj_state() helper, which takes a pointer to a kernel object as a first argument, uses mem_cgroup_from_obj() to get a RCU-protected memcg pointer and calls mod_memcg_state(). It allows to handle all possible configurations (CONFIG_VMAP_STACK and various THREAD_SIZE/PAGE_SIZE values) without spilling any memcg/kmem specifics into fork.c . Note: This is a special version of the patch created for stable backports. It contains code from the following two patches: - mm: memcg/slab: introduce mem_cgroup_from_obj() - mm: fork: fix kernel_stack memcg stats for various stack implementations [guro@fb.com: introduce mem_cgroup_from_obj()] Link: http://lkml.kernel.org/r/20200324004221.GA36662@carbon.dhcp.thefacebook.com Link: http://lkml.kernel.org/r/20200303233550.251375-1-guro@fb.com Fixes: 4d96ba353075 ("mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages") Signed-off-by: Roman Gushchin Reviewed-by: Shakeel Butt Acked-by: Johannes Weiner Cc: Michal Hocko Cc: Bharata B Rao Cc: Shakeel Butt Cc: Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 12 +++++++++++ kernel/fork.c | 4 +-- mm/memcontrol.c | 38 +++++++++++++++++++++++++++++++++++ 3 files changed, 52 insertions(+), 2 deletions(-) --- a/include/linux/memcontrol.h~mm-fork-fix-kernel_stack-memcg-stats-for-various-stack-implementations +++ a/include/linux/memcontrol.h @@ -695,6 +695,7 @@ static inline unsigned long lruvec_page_ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, int val); void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val); +void mod_memcg_obj_state(void *p, int idx, int val); static inline void mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, int val) @@ -1123,6 +1124,10 @@ static inline void __mod_lruvec_slab_sta __mod_node_page_state(page_pgdat(page), idx, val); } +static inline void mod_memcg_obj_state(void *p, int idx, int val) +{ +} + static inline unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, gfp_t gfp_mask, @@ -1427,6 +1432,8 @@ static inline int memcg_cache_id(struct return memcg ? memcg->kmemcg_id : -1; } +struct mem_cgroup *mem_cgroup_from_obj(void *p); + #else static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order) @@ -1468,6 +1475,11 @@ static inline void memcg_put_cache_ids(v { } +static inline struct mem_cgroup *mem_cgroup_from_obj(void *p) +{ + return NULL; +} + #endif /* CONFIG_MEMCG_KMEM */ #endif /* _LINUX_MEMCONTROL_H */ --- a/kernel/fork.c~mm-fork-fix-kernel_stack-memcg-stats-for-various-stack-implementations +++ a/kernel/fork.c @@ -397,8 +397,8 @@ static void account_kernel_stack(struct mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB, THREAD_SIZE / 1024 * account); - mod_memcg_page_state(first_page, MEMCG_KERNEL_STACK_KB, - account * (THREAD_SIZE / 1024)); + mod_memcg_obj_state(stack, MEMCG_KERNEL_STACK_KB, + account * (THREAD_SIZE / 1024)); } } --- a/mm/memcontrol.c~mm-fork-fix-kernel_stack-memcg-stats-for-various-stack-implementations +++ a/mm/memcontrol.c @@ -777,6 +777,17 @@ void __mod_lruvec_slab_state(void *p, en rcu_read_unlock(); } +void mod_memcg_obj_state(void *p, int idx, int val) +{ + struct mem_cgroup *memcg; + + rcu_read_lock(); + memcg = mem_cgroup_from_obj(p); + if (memcg) + mod_memcg_state(memcg, idx, val); + rcu_read_unlock(); +} + /** * __count_memcg_events - account VM events in a cgroup * @memcg: the memory cgroup @@ -2661,6 +2672,33 @@ static void commit_charge(struct page *p } #ifdef CONFIG_MEMCG_KMEM +/* + * Returns a pointer to the memory cgroup to which the kernel object is charged. + * + * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(), + * cgroup_mutex, etc. + */ +struct mem_cgroup *mem_cgroup_from_obj(void *p) +{ + struct page *page; + + if (mem_cgroup_disabled()) + return NULL; + + page = virt_to_head_page(p); + + /* + * Slab pages don't have page->mem_cgroup set because corresponding + * kmem caches can be reparented during the lifetime. That's why + * memcg_from_slab_page() should be used instead. + */ + if (PageSlab(page)) + return memcg_from_slab_page(page); + + /* All other pages use page->mem_cgroup */ + return page->mem_cgroup; +} + static int memcg_alloc_cache_id(void) { int id, size; _