From patchwork Wed Jul 26 15:32:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 126477 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:a985:0:b0:3e4:2afc:c1 with SMTP id t5csp499181vqo; Wed, 26 Jul 2023 09:01:44 -0700 (PDT) X-Google-Smtp-Source: APBJJlENoyEGZuvh8MX/YNSnv6oWpsAJXmAkKSjxEoKKHLUx8x1nSWrvM/Qb5lU/xMx3o/lRbY4m X-Received: by 2002:a17:903:124f:b0:1b8:865d:6e1d with SMTP id u15-20020a170903124f00b001b8865d6e1dmr2146990plh.51.1690387304469; Wed, 26 Jul 2023 09:01:44 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690387304; cv=none; d=google.com; s=arc-20160816; b=cGFeFRCJPh/FcS5j3M5EJBl2GPeslGpowrqfXauTOjW5VwVo2fNR1UVVkHG1VoXoee C8QDXe4jqdCKTUSzi5wDENcabYN0HsAdSGj3r8djM6tvHU4e/39QFn3JCueDHYHNpgKu h8N0vPQZtaMqZbbz+76D3r2LoDae4Ys3qi3STVhOSkFACl+Gb9FXHE3FXJeyxllEtVZE EpeYePhpyfIMcX74I5hr8yCV/agWb8xO2pxYmCFZlPc8x0NM+61CYQQHqyCZRg9u+X/t rowmF9If0Jjqzu6SJ0/aw9M5MbAJrHO4CiLeInKq+kzwuoU/YorAaSEcNrUDCUR7NSXD XtNQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:mime-version:date :dkim-signature; bh=6e7KuyR5qZ6xCXotERLteVBuiZtk31A4XosqK7/beqs=; fh=jmG0cbQBAwdux8Hz7jngnF2uBplH4M/FgvnJiAKVH6o=; b=E7qJarLVVSaqwfb6w3aZEBCYlsrMZVaoICRJJT20rRfCq3LZg4q3PgQ36kmX04T54h JB8HcluBCkD7nyCQrmb3TsbhiWc2KmyYpEzTwvvbdyLNbm4PUsMDAb2PmijyTIR6XUJV N2ZGm4xvLiEc+KvDWgErfczLhb5RS9hfvvS/vhRnWdWKeOwtAmU8ketGa8cKj93HOjT+ lNOxX419TqxNzWA3BOm47UFNplxUioV6JabNWLpAAj/38YLwZvL2i+8e9AzRTaw1DoKg XEJh99+RgRt5f9NhE83yTONNU2ORKwxjDZBorFTOwHN77Di+Uxlaa7SyWZEq6HEDB8bC vUiQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=hfmPlDHM; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id kx14-20020a170902f94e00b001ae4a01a7e0si12707201plb.236.2023.07.26.09.01.20; Wed, 26 Jul 2023 09:01:44 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=hfmPlDHM; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232448AbjGZPc3 (ORCPT + 99 others); Wed, 26 Jul 2023 11:32:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231372AbjGZPc2 (ORCPT ); Wed, 26 Jul 2023 11:32:28 -0400 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0B022136 for ; Wed, 26 Jul 2023 08:32:26 -0700 (PDT) Received: by mail-pg1-x54a.google.com with SMTP id 41be03b00d2f7-5635233876bso3597008a12.0 for ; Wed, 26 Jul 2023 08:32:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690385546; x=1690990346; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=6e7KuyR5qZ6xCXotERLteVBuiZtk31A4XosqK7/beqs=; b=hfmPlDHM//CdQxH+FNIMT9hQbrC5TE6d8oSs8Vv3mFiP4Yxwh7Xq1zE+ghsQM8ajLS olrZ91m4ZNbAzyVhUJhdPivUPF6QJQRQAayqxgM/FN2zEJid/T6tjet02urwcqQxVKF1 pCg+I6e+Ta528ZDcEtCTuCt6TiQlXHF0HP2YCupLkIaW60OXug/z+5yCXlDH2YCLILTA PUkeLHGe6j/IAncLqmGK1bNCU6UJ4OjkbCI4ofsyLm+1RTbDqmHfZec680qFCaCQj7om es60ZBquPQbMI1+MuI/U2OxUwsiZfBb73DZrgdsIzZP2dRli5JaZWa5K+FXgQMJU/qLp hJMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690385546; x=1690990346; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=6e7KuyR5qZ6xCXotERLteVBuiZtk31A4XosqK7/beqs=; b=PD4xDLj3EUmoYPiGBYwoirlh/ZYDjK/5QrkOmoBizjzlt9IGM0XFup65AoFgOtfZf5 Oah1/u3u30OiUcw42x8Ne6paU4Re/bpc/7ALT1XwGWwOB4G9UezaRwEwb7p21j96S7ex kYPTtoqc5apUIerFWSDFimbVU8haMHAiC36CLTzcfGRWVFOKrUPJ5W13b3puGXlb1Y3t I9ky7HZwprYYnqXjW4OHWmxr+qYDUt0TmK4+psCDUr0d/LKrsj+89bT6IeHoDjR3mE6a QtLgYP1GxULatHOufarcLSGKpSDHxnc5NWkMwPSFjow3O48V+o3xZPNHing0b3SLAi+a q6/Q== X-Gm-Message-State: ABy/qLanIKV0VGeOAeW/BuIAbqdysQnccr9GfA2LaecYgmn7Fgd4Ltpc 078WeI8ff/ZAaiZB83uvAKMQcf7MRRWQAbSM X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a63:7f1c:0:b0:553:3ba2:f36 with SMTP id a28-20020a637f1c000000b005533ba20f36mr10273pgd.9.1690385546207; Wed, 26 Jul 2023 08:32:26 -0700 (PDT) Date: Wed, 26 Jul 2023 15:32:22 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.41.0.487.g6d72f3e995-goog Message-ID: <20230726153223.821757-1-yosryahmed@google.com> Subject: [PATCH] mm: memcg: use rstat for non-hierarchical stats From: Yosry Ahmed To: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Yosry Ahmed X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1772499409836900245 X-GMAIL-MSGID: 1772499558323151874 Currently, memcg uses rstat to maintain hierarchical stats. The rstat framework keeps track of which cgroups have updates on which cpus. For non-hierarchical stats, as memcg moved to rstat, they are no longer readily available as counters. Instead, the percpu counters for a given stat need to be summed to get the non-hierarchical stat value. This causes a performance regression when reading non-hierarchical stats on kernels where memcg moved to using rstat. This is especially visible when reading memory.stat on cgroup v1. There are also some code paths internal to the kernel that read such non-hierarchical stats. It is inefficient to iterate and sum counters in all cpus when the rstat framework knows exactly when a percpu counter has an update. Instead, maintain cpu-aggregated non-hierarchical counters for each stat. During an rstat flush, keep those updated as well. When reading non-hierarchical stats, we no longer need to iterate cpus, we just need to read the maintainer counters, similar to hierarchical stats. A caveat is that we now a stats flush before reading local/non-hierarchical stats through {memcg/lruvec}_page_state_local() or memcg_events_local(), where we previously only needed a flush to read hierarchical stats. Most contexts reading non-hierarchical stats are already doing a flush, add a flush to the only missing context in count_shadow_nodes(). With this patch, reading memory.stat from 1000 memcgs is 3x faster on a machine with 256 cpus on cgroup v1: # for i in $(seq 1000); do mkdir /sys/fs/cgroup/memory/cg$i; done # time cat /dev/cgroup/memory/cg*/memory.stat > /dev/null real 0m0.125s user 0m0.005s sys 0m0.120s After: real 0m0.032s user 0m0.005s sys 0m0.027s Signed-off-by: Yosry Ahmed --- include/linux/memcontrol.h | 7 ++++--- mm/memcontrol.c | 32 +++++++++++++++++++------------- mm/workingset.c | 1 + 3 files changed, 24 insertions(+), 16 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 5818af8eca5a..a9f2861a57a5 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -112,6 +112,9 @@ struct lruvec_stats { /* Aggregated (CPU and subtree) state */ long state[NR_VM_NODE_STAT_ITEMS]; + /* Non-hierarchical (CPU aggregated) state */ + long state_local[NR_VM_NODE_STAT_ITEMS]; + /* Pending child counts during tree propagation */ long state_pending[NR_VM_NODE_STAT_ITEMS]; }; @@ -1020,14 +1023,12 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec, { struct mem_cgroup_per_node *pn; long x = 0; - int cpu; if (mem_cgroup_disabled()) return node_page_state(lruvec_pgdat(lruvec), idx); pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec); - for_each_possible_cpu(cpu) - x += per_cpu(pn->lruvec_stats_percpu->state[idx], cpu); + x = READ_ONCE(pn->lruvec_stats.state_local[idx]); #ifdef CONFIG_SMP if (x < 0) x = 0; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e8ca4bdcb03c..90a22637818e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -742,6 +742,10 @@ struct memcg_vmstats { long state[MEMCG_NR_STAT]; unsigned long events[NR_MEMCG_EVENTS]; + /* Non-hierarchical (CPU aggregated) page state & events */ + long state_local[MEMCG_NR_STAT]; + unsigned long events_local[NR_MEMCG_EVENTS]; + /* Pending child counts during tree propagation */ long state_pending[MEMCG_NR_STAT]; unsigned long events_pending[NR_MEMCG_EVENTS]; @@ -775,11 +779,8 @@ void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val) /* idx can be of type enum memcg_stat_item or node_stat_item. */ static unsigned long memcg_page_state_local(struct mem_cgroup *memcg, int idx) { - long x = 0; - int cpu; + long x = READ_ONCE(memcg->vmstats->state_local[idx]); - for_each_possible_cpu(cpu) - x += per_cpu(memcg->vmstats_percpu->state[idx], cpu); #ifdef CONFIG_SMP if (x < 0) x = 0; @@ -926,16 +927,12 @@ static unsigned long memcg_events(struct mem_cgroup *memcg, int event) static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event) { - long x = 0; - int cpu; int index = memcg_events_index(event); if (index < 0) return 0; - for_each_possible_cpu(cpu) - x += per_cpu(memcg->vmstats_percpu->events[index], cpu); - return x; + return READ_ONCE(memcg->vmstats->events_local[index]); } static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, @@ -5526,7 +5523,7 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) struct mem_cgroup *memcg = mem_cgroup_from_css(css); struct mem_cgroup *parent = parent_mem_cgroup(memcg); struct memcg_vmstats_percpu *statc; - long delta, v; + long delta, delta_cpu, v; int i, nid; statc = per_cpu_ptr(memcg->vmstats_percpu, cpu); @@ -5542,9 +5539,11 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) memcg->vmstats->state_pending[i] = 0; /* Add CPU changes on this level since the last flush */ + delta_cpu = 0; v = READ_ONCE(statc->state[i]); if (v != statc->state_prev[i]) { - delta += v - statc->state_prev[i]; + delta_cpu = v - statc->state_prev[i]; + delta += delta_cpu; statc->state_prev[i] = v; } @@ -5553,6 +5552,7 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) /* Aggregate counts on this level and propagate upwards */ memcg->vmstats->state[i] += delta; + memcg->vmstats->state_local[i] += delta_cpu; if (parent) parent->vmstats->state_pending[i] += delta; } @@ -5562,9 +5562,11 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) if (delta) memcg->vmstats->events_pending[i] = 0; + delta_cpu = 0; v = READ_ONCE(statc->events[i]); if (v != statc->events_prev[i]) { - delta += v - statc->events_prev[i]; + delta_cpu = v - statc->events_prev[i]; + delta += delta_cpu; statc->events_prev[i] = v; } @@ -5572,6 +5574,7 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) continue; memcg->vmstats->events[i] += delta; + memcg->vmstats->events_local[i] += delta_cpu; if (parent) parent->vmstats->events_pending[i] += delta; } @@ -5591,9 +5594,11 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) if (delta) pn->lruvec_stats.state_pending[i] = 0; + delta_cpu = 0; v = READ_ONCE(lstatc->state[i]); if (v != lstatc->state_prev[i]) { - delta += v - lstatc->state_prev[i]; + delta_cpu = v - lstatc->state_prev[i]; + delta += delta_cpu; lstatc->state_prev[i] = v; } @@ -5601,6 +5606,7 @@ static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state *css, int cpu) continue; pn->lruvec_stats.state[i] += delta; + pn->lruvec_stats.state_local[i] += delta_cpu; if (ppn) ppn->lruvec_stats.state_pending[i] += delta; } diff --git a/mm/workingset.c b/mm/workingset.c index 4686ae363000..da58a26d0d4d 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -664,6 +664,7 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, struct lruvec *lruvec; int i; + mem_cgroup_flush_stats(); lruvec = mem_cgroup_lruvec(sc->memcg, NODE_DATA(sc->nid)); for (pages = 0, i = 0; i < NR_LRU_LISTS; i++) pages += lruvec_page_state_local(lruvec,