From patchwork Fri Apr 2 19:16:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Schatzberg X-Patchwork-Id: 12181423 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 5D59FC433ED for ; Fri, 2 Apr 2021 19:17:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 246C061167 for ; Fri, 2 Apr 2021 19:17:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236380AbhDBTRJ (ORCPT ); Fri, 2 Apr 2021 15:17:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52014 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236346AbhDBTRH (ORCPT ); Fri, 2 Apr 2021 15:17:07 -0400 Received: from mail-qk1-x72e.google.com (mail-qk1-x72e.google.com [IPv6:2607:f8b0:4864:20::72e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16015C0613E6; Fri, 2 Apr 2021 12:17:05 -0700 (PDT) Received: by mail-qk1-x72e.google.com with SMTP id g20so6118505qkk.1; Fri, 02 Apr 2021 12:17:05 -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=+KHwE2AhOFIJnmIDNMc1DwLLUBXXvq8Ulhj1XiQvB5I=; b=BXaI/FORtIxMvTFmIa9kbNY62q1FS0JEgTex/Q4f5VKgABUmi+/JkKYUVd2RTFv6yX wQpyGa4OYO9YjtvIpxculFHDo4m2gm+Vzqr9RaiE6KrDSi3PpyuOE2z2Sfel7jL4nlaM +1dumXxo87f3ZSVnSwmw9/erMj2QJhMqIEUASqej03TSvjMnU7qVQwGjzBTO1eqV1vk5 MTR88N6jcgDZgG3+Rnjn8dwnyoMspRBjvQnLmA5lMFwM5MuNFuuNnBmBR2Ii0hX38FLR sJtWQgorXlOFKPbMtdD2T/qcx/NYMCe9Q/onzQFSiHEjwFtt1YIbwb050CgTp4hyJMT7 FXKw== 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=+KHwE2AhOFIJnmIDNMc1DwLLUBXXvq8Ulhj1XiQvB5I=; b=kdVxHi8VWc9QVW1db+sDJo/RJ7Xj4ar1aVoQEmE3bjVLqADBYpPdFM6iEAsbIzAo81 XnusAesJLWXCwFC1cKL7bwEFFk0Na+6gEzuUqYNxPGWBk+sfn81uMFM6uUnb5mIxAUm/ d2JRMh0FRvxh7TPnCgeHZnbpG90w+UVJq6WGpGYtglKOh0OmYS0O4c8ANkN/OT/cWTr+ 27KASAJzYtIRy5PGgKnxLA8Can8IrWJzsyENCGLEaNvXTjAOss9BJVwhaQsrV7tDW7xj 0SS5gUb+zYMBnGEVZiiS4wghMaAs3S40f45QBWbWUmq6yK4Ll35KV1Qpq1yLr8a5DGF+ 1ehw== X-Gm-Message-State: AOAM531dbMQomeXwObhhvmzjFjUvmE/48aNMgC2B2pKsLizqe/dquOVO /C6YKmK2ywMO2n6871e0ARg= X-Google-Smtp-Source: ABdhPJxMGcXT3JcQRvQnajZ/JKy0cNPymTLKlftpElVkfeeC60c7QmwgaMW2l1kPWw/4acp3YR2Kbw== X-Received: by 2002:a05:620a:209d:: with SMTP id e29mr14597432qka.316.1617391024335; Fri, 02 Apr 2021 12:17:04 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:ae82]) by smtp.gmail.com with ESMTPSA id 8sm8083426qkc.32.2021.04.02.12.17.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Apr 2021 12:17:03 -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 , Muchun Song , Yang Shi , Alex Shi , Alexander Duyck , 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: Fri, 2 Apr 2021 12:16:33 -0700 Message-Id: <20210402191638.3249835-3-schatzberg.dan@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210402191638.3249835-1-schatzberg.dan@gmail.com> References: <20210402191638.3249835-1-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 Reviewed-by: Muchun Song --- mm/filemap.c | 2 +- mm/memcontrol.c | 48 +++++++++++++++++++++++++++++++----------------- mm/shmem.c | 4 ++-- 3 files changed, 34 insertions(+), 20 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index c03463cb72d6..38648f7d2106 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 c0b83a396299..d2939d6602b3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -886,13 +886,24 @@ 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; +} + /** * 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) { @@ -901,13 +912,23 @@ 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)) { + memcg = active_memcg(); + if (unlikely(memcg)) { + /* remote memcg must hold a ref */ + css_get(&memcg->css); + return memcg; + } + mm = current->mm; + } + rcu_read_lock(); do { - /* - * 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)) memcg = root_mem_cgroup; else { @@ -921,14 +942,6 @@ 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 bool memcg_kmem_bypass(void) { /* Allow remote memcg charging from any context. */ @@ -6537,7 +6550,8 @@ 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 5cfd2fb6e52b..524fa5aa0459 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);