From patchwork Mon Mar 29 14:48:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 12170293 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=-13.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 037A4C433DB for ; Mon, 29 Mar 2021 14:50:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C746B6196C for ; Mon, 29 Mar 2021 14:50:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231246AbhC2Otw (ORCPT ); Mon, 29 Mar 2021 10:49:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231222AbhC2OtO (ORCPT ); Mon, 29 Mar 2021 10:49:14 -0400 Received: from mail-qv1-xf30.google.com (mail-qv1-xf30.google.com [IPv6:2607:f8b0:4864:20::f30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D544AC061574; Mon, 29 Mar 2021 07:49:12 -0700 (PDT) Received: by mail-qv1-xf30.google.com with SMTP id 30so6539265qva.9; Mon, 29 Mar 2021 07:49:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Rthy9P0Uh0koEJAABJmO03Eire712vne5xpQyDeAJI4=; b=XZIDOotpCQUmqCUTzgdbM8HJwIVy95s2B1jNzXPmJ4vLobO925VPGi5h2cxuRcOr6m P0Gn0hmTY+Djt+3Br3i5bCY7ohQ0YBNJ+0neLiCdBePj6yBCOQKOPVBI0mpDh/Ylu7HA tTS8doZTk1LNXCgmrl5aJtIkOoLN2CZMqqjTlG7p5PXZ1/3ww3JGfDauAwyMJ4/hcEoz lfw+rrWA2eJ3fp65V/B0T7HVjflxGy0y1HBEStGDoaKwE4Q5xA0TXGVe5gh5Z5blKadd 8UaXcRFJVASTjFWpG8SevupS9sLNcFSZlAPrCsiMYIVA8JA0DDpV1hsNdCy7COqs0MsP yMMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Rthy9P0Uh0koEJAABJmO03Eire712vne5xpQyDeAJI4=; b=GdEKyXFjEAMIJrcZ/eyYgDY6if87hYX8U91XAb9GrneJzPSSCu/I7/9LXIkS2IM0P3 cJd7I+aSTOmQ9CPcItyphqGl4YLIA2lN9ODDfSeZXE47XPYiyqFwqa3n13Sh5OvdMy5N a3DDu7rIGyu69YxFivVqJVBwjTFhgBAZsQcAKxC80nIHdr2fjPVuFaIfAIacj/SUQjVX zWjwtg2xTTYxVd3iiUFJd2f8Bkik/tWmRRHfJYkjvnj3mBMxkgcB+4khmO10dtSQry8B dDDEn5f8WOU3e9A963WVmsAq/jpWGvaIiMhbQW5DjMG7BAufa3CqlwoS6qVy6LqgqOs6 T/6w== X-Gm-Message-State: AOAM531gsA7VRLkPIBnNMH9D7eWGfcoygURMts/JHn/SD/eeMgvYQ43T LdKF5iOVyTHeMlx0Epy2oa4= X-Google-Smtp-Source: ABdhPJyrPwiFHe9h8ZF/GhbLu+UwDgiEfytWhwG8ZmTnL/HS3e9ZG9nz3oT6qCsy2JGljwvTpeBPmw== X-Received: by 2002:a0c:80ca:: with SMTP id 68mr25705154qvb.12.1617029351737; Mon, 29 Mar 2021 07:49:11 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:6ffc]) by smtp.gmail.com with ESMTPSA id d14sm14255708qkg.33.2021.03.29.07.49.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Mar 2021 07:49:11 -0700 (PDT) From: Dan Schatzberg Cc: Jens Axboe , Tejun Heo , Zefan Li , Johannes Weiner , Andrew Morton , Michal Hocko , Vladimir Davydov , Hugh Dickins , Shakeel Butt , Roman Gushchin , Yang Shi , Muchun Song , Alex Shi , Alexander Duyck , Yafang Shao , Wei Yang , linux-block@vger.kernel.org (open list:BLOCK LAYER), linux-kernel@vger.kernel.org (open list), cgroups@vger.kernel.org (open list:CONTROL GROUP (CGROUP)), linux-mm@kvack.org (open list:MEMORY MANAGEMENT), Chris Down Subject: [PATCH 2/3] mm: Charge active memcg when no mm is set Date: Mon, 29 Mar 2021 07:48:24 -0700 Message-Id: <20210329144829.1834347-3-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210329144829.1834347-1-schatzberg.dan@gmail.com> References: <20210329144829.1834347-1-schatzberg.dan@gmail.com> MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org set_active_memcg() worked for kernel allocations but was silently ignored for user pages. This patch establishes a precedence order for who gets charged: 1. If there is a memcg associated with the page already, that memcg is charged. This happens during swapin. 2. If an explicit mm is passed, mm->memcg is charged. This happens during page faults, which can be triggered in remote VMs (eg gup). 3. Otherwise consult the current process context. If there is an active_memcg, use that. Otherwise, current->mm->memcg. Previously, if a NULL mm was passed to mem_cgroup_charge (case 3) it would always charge the root cgroup. Now it looks up the active_memcg first (falling back to charging the root cgroup if not set). Signed-off-by: Dan Schatzberg Acked-by: Johannes Weiner Acked-by: Tejun Heo Acked-by: Chris Down Reviewed-by: Shakeel Butt --- mm/filemap.c | 2 +- mm/memcontrol.c | 72 ++++++++++++++++++++++++++++--------------------- mm/shmem.c | 4 +-- 3 files changed, 44 insertions(+), 34 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index eeeb8e2cc36a..63fd980e863a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -872,7 +872,7 @@ noinline int __add_to_page_cache_locked(struct page *page, page->index = offset; if (!huge) { - error = mem_cgroup_charge(page, current->mm, gfp); + error = mem_cgroup_charge(page, NULL, gfp); if (error) goto error; charged = true; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 668d1d7c2645..adc618814fd2 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -884,13 +884,38 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) } EXPORT_SYMBOL(mem_cgroup_from_task); +static __always_inline struct mem_cgroup *active_memcg(void) +{ + if (in_interrupt()) + return this_cpu_read(int_active_memcg); + else + return current->active_memcg; +} + +static __always_inline struct mem_cgroup *get_active_memcg(void) +{ + struct mem_cgroup *memcg; + + rcu_read_lock(); + memcg = active_memcg(); + /* remote memcg must hold a ref. */ + if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css))) + memcg = root_mem_cgroup; + rcu_read_unlock(); + + return memcg; +} + /** * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg. * @mm: mm from which memcg should be extracted. It can be NULL. * - * Obtain a reference on mm->memcg and returns it if successful. Otherwise - * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is - * returned. + * Obtain a reference on mm->memcg and returns it if successful. If mm + * is NULL, then the memcg is chosen as follows: + * 1) The active memcg, if set. + * 2) current->mm->memcg, if available + * 3) root memcg + * If mem_cgroup is disabled, NULL is returned. */ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) { @@ -899,13 +924,19 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) if (mem_cgroup_disabled()) return NULL; + /* + * Page cache insertions can happen without an + * actual mm context, e.g. during disk probing + * on boot, loopback IO, acct() writes etc. + */ + if (unlikely(!mm)) { + if (unlikely(active_memcg())) + return get_active_memcg(); + mm = current->mm; + } + rcu_read_lock(); do { - /* - * Page cache insertions can happen withou an - * actual mm context, e.g. during disk probing - * on boot, loopback IO, acct() writes etc. - */ if (unlikely(!mm)) memcg = root_mem_cgroup; else { @@ -919,28 +950,6 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm) } EXPORT_SYMBOL(get_mem_cgroup_from_mm); -static __always_inline struct mem_cgroup *active_memcg(void) -{ - if (in_interrupt()) - return this_cpu_read(int_active_memcg); - else - return current->active_memcg; -} - -static __always_inline struct mem_cgroup *get_active_memcg(void) -{ - struct mem_cgroup *memcg; - - rcu_read_lock(); - memcg = active_memcg(); - /* remote memcg must hold a ref. */ - if (memcg && WARN_ON_ONCE(!css_tryget(&memcg->css))) - memcg = root_mem_cgroup; - rcu_read_unlock(); - - return memcg; -} - static __always_inline bool memcg_kmem_bypass(void) { /* Allow remote memcg charging from any context. */ @@ -6549,7 +6558,8 @@ static int __mem_cgroup_charge(struct page *page, struct mem_cgroup *memcg, * @gfp_mask: reclaim mode * * Try to charge @page to the memcg that @mm belongs to, reclaiming - * pages according to @gfp_mask if necessary. + * pages according to @gfp_mask if necessary. if @mm is NULL, try to + * charge to the active memcg. * * Do not use this for pages allocated for swapin. * diff --git a/mm/shmem.c b/mm/shmem.c index 78ab81a62b29..7c09276125d5 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1694,7 +1694,7 @@ static int shmem_swapin_page(struct inode *inode, pgoff_t index, { struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); - struct mm_struct *charge_mm = vma ? vma->vm_mm : current->mm; + struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL; struct page *page; swp_entry_t swap; int error; @@ -1815,7 +1815,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, } sbinfo = SHMEM_SB(inode->i_sb); - charge_mm = vma ? vma->vm_mm : current->mm; + charge_mm = vma ? vma->vm_mm : NULL; page = pagecache_get_page(mapping, index, FGP_ENTRY | FGP_HEAD | FGP_LOCK, 0);