From nobody Mon Feb 9 17:22:12 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDC3FEB64D7 for ; Wed, 21 Jun 2023 18:17:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231754AbjFUSRc (ORCPT ); Wed, 21 Jun 2023 14:17:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45164 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231284AbjFUSRO (ORCPT ); Wed, 21 Jun 2023 14:17:14 -0400 Received: from mail-pl1-x649.google.com (mail-pl1-x649.google.com [IPv6:2607:f8b0:4864:20::649]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A58C519A9 for ; Wed, 21 Jun 2023 11:17:12 -0700 (PDT) Received: by mail-pl1-x649.google.com with SMTP id d9443c01a7336-1b51ba96cb4so47407265ad.3 for ; Wed, 21 Jun 2023 11:17:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1687371432; x=1689963432; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=WHNe3JpSW3qQzxOEOwM65k3PJvHd1TN91bqMS64mhVU=; b=MVxoxG2UJlFie+EE1fYVqH+HX9TC4DlWD+BHaHeLLJHx6Jxtu/DFPoB7LMunGaFsjp //1r8XRL5aRB7zBg/F9i2/UzJRwBnWI703NA2RibkRlg3moTohk16JYHt+4fDzmFU/lF J9YtXBEapHmbZvYFfm/TI8AJIbFeBlyUEi/8WTkJDyLh1QqStF5YuF45YeCkuAvBUg6q NXcwAJutswIyTGJSIujATExtb/Ttp52WLyhCNKELa/UsjoeripP+vytdkFYr7Yz97nyD KqivdIfLL9LXaMZgmLAkFXoY67oftZj07I4GBXIVmzIBpBgPbNV47l4Y63aZ1yUYhhRO y9Pg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687371432; x=1689963432; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WHNe3JpSW3qQzxOEOwM65k3PJvHd1TN91bqMS64mhVU=; b=mFQ8sjENVPeHX1ZO0wVQ/2nmQFa+hSbYIrottb46rXgMqqN0E4g7xEcL8clbEZAJSN v8SNeCGEIOPPXtDhcHHMs37F6BoT6bKWU4P164Zc9q7zQNhahlg5Syi6UAKw9r4Mmfc1 HU58KtOqlS+gqnEx+eSpPphJptDTnP1pKRk1spNmZ33QIxoOKmmv64DzK1c8T3CLGOMZ e8c35AYikAlw80nkuEc6t2zMMAG7kdCFbuVk9IsVCiu+TKbL59YaT0MB3sIcXFnrIOfd mIYj2VM8s2C3OFYvDaIBT4M/jbBH6Q6Piw1Fs6ZGbMZiNnLfEHsJukeYCvocNnM6Kyx3 WcmA== X-Gm-Message-State: AC+VfDxWxuY6BljN3iV2EDYBGOCv9XKHWq3yKhLoOa3R+HE591sakGat 48Ey//qN23SISoIt+ypquSWHQDNHT+w6 X-Google-Smtp-Source: ACHHUZ4KOLt5QOgx4FB1LIr7plEmFPeCuljE0b32YnY15ZVuYdQlAh+psvGrpKhQXH2ap2Bx2Nfl0jTMoIC/ X-Received: from yuanchu.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:4024]) (user=yuanchu job=sendgmr) by 2002:a17:902:efd1:b0:1b3:d6be:4680 with SMTP id ja17-20020a170902efd100b001b3d6be4680mr2304661plb.13.1687371432115; Wed, 21 Jun 2023 11:17:12 -0700 (PDT) Date: Wed, 21 Jun 2023 18:04:53 +0000 In-Reply-To: <20230621180454.973862-1-yuanchu@google.com> Mime-Version: 1.0 References: <20230621180454.973862-1-yuanchu@google.com> X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: <20230621180454.973862-6-yuanchu@google.com> Subject: [RFC PATCH v2 5/6] mm: add per-memcg reaccess histogram From: Yuanchu Xie To: Greg Kroah-Hartman , "Rafael J . Wysocki" , "Michael S . Tsirkin" , David Hildenbrand , Jason Wang , Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Yu Zhao , Kefeng Wang , Kairui Song , Yosry Ahmed , Yuanchu Xie , "T . J . Alumbaugh" Cc: Wei Xu , SeongJae Park , Sudarshan Rajagopalan , kai.huang@intel.com, hch@lst.de, jon@nutanix.com, Aneesh Kumar K V , Matthew Wilcox , Vasily Averin , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, cgroups@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" A reaccess refers to detecting an access on a page via refault or access bit harvesting after the initial access. Similar to the working set histogram, the reaccess histogram breaks down reaccesses into user-defined bins. Currently it only tracks reaccesses from access bit harvesting, and the plan is to include refaults in the same histogram by pulling information from folio->mapping->i_pages shadow entry for swapped out pages. Signed-off-by: T.J. Alumbaugh Signed-off-by: Yuanchu Xie --- include/linux/wsr.h | 9 +++- mm/memcontrol.c | 89 ++++++++++++++++++++++++++++++++++++++ mm/vmscan.c | 6 ++- mm/wsr.c | 101 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 203 insertions(+), 2 deletions(-) diff --git a/include/linux/wsr.h b/include/linux/wsr.h index d45f7cc0672ac..68246734679cd 100644 --- a/include/linux/wsr.h +++ b/include/linux/wsr.h @@ -26,11 +26,14 @@ struct ws_bin { struct wsr { /* protects bins */ struct mutex bins_lock; + /* protects reaccess_bins */ + struct mutex reaccess_bins_lock; struct kernfs_node *notifier; unsigned long timestamp; unsigned long report_threshold; unsigned long refresh_threshold; struct ws_bin bins[MAX_NR_BINS]; + struct ws_bin reaccess_bins[MAX_NR_BINS]; }; =20 void wsr_register_node(struct node *node); @@ -48,6 +51,7 @@ ssize_t wsr_intervals_ms_parse(char *src, struct ws_bin *= bins); */ void wsr_refresh(struct wsr *wsr, struct mem_cgroup *root, struct pglist_data *pgdat); +void report_reaccess(struct lruvec *lruvec, struct lru_gen_mm_walk *walk); void report_ws(struct pglist_data *pgdat, struct scan_control *sc); #else struct ws_bin; @@ -71,7 +75,10 @@ static inline ssize_t wsr_intervals_ms_parse(char *src, = struct ws_bin *bins) return -EINVAL; } static inline void wsr_refresh(struct wsr *wsr, struct mem_cgroup *root, - struct pglist_data *pgdat) + struct pglist_data *pgdat) +{ +} +static inline void report_reaccess(struct lruvec *lruvec, struct lru_gen_m= m_walk *walk) { } static inline void report_ws(struct pglist_data *pgdat, struct scan_contro= l *sc) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index edf5bb31bb19c..b901982d659d2 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6736,6 +6736,56 @@ static ssize_t memory_wsr_intervals_ms_write(struct = kernfs_open_file *of, return err ?: nbytes; } =20 +static int memory_reaccess_intervals_ms_show(struct seq_file *m, void *v) +{ + int nid; + struct mem_cgroup *memcg =3D mem_cgroup_from_seq(m); + + for_each_node_state(nid, N_MEMORY) { + struct wsr *wsr; + struct ws_bin *bin; + + wsr =3D lruvec_wsr(mem_cgroup_lruvec(memcg, NODE_DATA(nid))); + mutex_lock(&wsr->reaccess_bins_lock); + seq_printf(m, "N%d=3D", nid); + for (bin =3D wsr->reaccess_bins; bin->idle_age !=3D -1; bin++) + seq_printf(m, "%u,", jiffies_to_msecs(bin->idle_age)); + mutex_unlock(&wsr->reaccess_bins_lock); + + seq_printf(m, "%lld ", LLONG_MAX); + } + seq_putc(m, '\n'); + + return 0; +} + +static ssize_t memory_reaccess_intervals_ms_write(struct kernfs_open_file = *of, + char *buf, size_t nbytes, + loff_t off) +{ + unsigned int nid; + int err; + struct wsr *wsr; + struct ws_bin *bins; + struct mem_cgroup *memcg =3D mem_cgroup_from_css(of_css(of)); + + bins =3D kzalloc(sizeof(wsr->reaccess_bins), GFP_KERNEL); + if (!bins) + return -ENOMEM; + + err =3D memory_wsr_intervals_ms_parse(of, buf, nbytes, &nid, bins); + if (err) + goto failed; + + wsr =3D lruvec_wsr(mem_cgroup_lruvec(memcg, NODE_DATA(nid))); + mutex_lock(&wsr->reaccess_bins_lock); + memcpy(wsr->reaccess_bins, bins, sizeof(wsr->reaccess_bins)); + mutex_unlock(&wsr->reaccess_bins_lock); +failed: + kfree(bins); + return err ?: nbytes; +} + static int memory_wsr_refresh_ms_show(struct seq_file *m, void *v) { int nid; @@ -6874,6 +6924,34 @@ __poll_t memory_wsr_histogram_poll(struct kernfs_ope= n_file *of, return DEFAULT_POLLMASK | EPOLLPRI; return DEFAULT_POLLMASK; } + +static int memory_reaccess_histogram_show(struct seq_file *m, void *v) +{ + int nid; + struct mem_cgroup *memcg =3D mem_cgroup_from_seq(m); + + for_each_node_state(nid, N_MEMORY) { + struct wsr *wsr =3D + lruvec_wsr(mem_cgroup_lruvec(memcg, NODE_DATA(nid))); + struct ws_bin *bin; + + seq_printf(m, "N%d\n", nid); + + mutex_lock(&wsr->reaccess_bins_lock); + wsr_refresh(wsr, memcg, NODE_DATA(nid)); + for (bin =3D wsr->reaccess_bins; bin->idle_age !=3D -1; bin++) + seq_printf(m, "%u anon=3D%lu file=3D%lu\n", + jiffies_to_msecs(bin->idle_age), + bin->nr_pages[0], bin->nr_pages[1]); + + seq_printf(m, "%lld anon=3D%lu file=3D%lu\n", LLONG_MAX, + bin->nr_pages[0], bin->nr_pages[1]); + + mutex_unlock(&wsr->reaccess_bins_lock); + } + + return 0; +} #endif =20 static struct cftype memory_files[] =3D { @@ -6969,6 +7047,17 @@ static struct cftype memory_files[] =3D { .seq_show =3D memory_wsr_histogram_show, .poll =3D memory_wsr_histogram_poll, }, + { + .name =3D "reaccess.intervals_ms", + .flags =3D CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE, + .seq_show =3D memory_reaccess_intervals_ms_show, + .write =3D memory_reaccess_intervals_ms_write, + }, + { + .name =3D "reaccess.histogram", + .flags =3D CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE, + .seq_show =3D memory_reaccess_histogram_show, + }, #endif {} /* terminate */ }; diff --git a/mm/vmscan.c b/mm/vmscan.c index ba254b6e91e19..bc8c026ceef0d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4226,6 +4226,7 @@ static void walk_mm(struct lruvec *lruvec, struct mm_= struct *mm, struct lru_gen_ mem_cgroup_unlock_pages(); =20 if (walk->batched) { + report_reaccess(lruvec, walk); spin_lock_irq(&lruvec->lru_lock); reset_batch_size(lruvec, walk); spin_unlock_irq(&lruvec->lru_lock); @@ -5079,11 +5080,14 @@ static int evict_folios(struct lruvec *lruvec, stru= ct scan_control *sc, int swap sc->nr_scanned -=3D folio_nr_pages(folio); } =20 + walk =3D current->reclaim_state->mm_walk; + if (walk && walk->batched) + report_reaccess(lruvec, walk); + spin_lock_irq(&lruvec->lru_lock); =20 move_folios_to_lru(lruvec, &list); =20 - walk =3D current->reclaim_state->mm_walk; if (walk && walk->batched) reset_batch_size(lruvec, walk); =20 diff --git a/mm/wsr.c b/mm/wsr.c index cd045ade5e9ba..a63d678e64f8b 100644 --- a/mm/wsr.c +++ b/mm/wsr.c @@ -23,8 +23,10 @@ void wsr_init(struct lruvec *lruvec) struct wsr *wsr =3D lruvec_wsr(lruvec); =20 mutex_init(&wsr->bins_lock); + mutex_init(&wsr->reaccess_bins_lock); wsr->bins[0].idle_age =3D -1; wsr->notifier =3D NULL; + wsr->reaccess_bins[0].idle_age =3D -1; } =20 void wsr_destroy(struct lruvec *lruvec) @@ -32,6 +34,7 @@ void wsr_destroy(struct lruvec *lruvec) struct wsr *wsr =3D lruvec_wsr(lruvec); =20 mutex_destroy(&wsr->bins_lock); + mutex_destroy(&wsr->reaccess_bins_lock); memset(wsr, 0, sizeof(*wsr)); } =20 @@ -172,6 +175,104 @@ void refresh_wsr(struct wsr *wsr, struct mem_cgroup *= root, cond_resched(); } while ((memcg =3D mem_cgroup_iter(root, memcg, NULL))); } + +static void collect_reaccess_locked(struct wsr *wsr, + struct lru_gen_struct *lrugen, + struct lru_gen_mm_walk *walk) +{ + int gen, type, zone; + unsigned long curr_timestamp =3D jiffies; + unsigned long max_seq =3D READ_ONCE(walk->max_seq); + unsigned long min_seq[ANON_AND_FILE] =3D { + READ_ONCE(lrugen->min_seq[LRU_GEN_ANON]), + READ_ONCE(lrugen->min_seq[LRU_GEN_FILE]), + }; + + for (type =3D 0; type < ANON_AND_FILE; type++) { + unsigned long seq; + struct ws_bin *bin =3D wsr->reaccess_bins; + + lockdep_assert_held(&wsr->reaccess_bins_lock); + /* Skip max_seq because a reaccess moves a page from another seq + * to max_seq. We use the negative change in page count from + * other seqs to track the number of reaccesses. + */ + for (seq =3D max_seq - 1; seq + 1 > min_seq[type]; seq--) { + long error; + int next_gen; + unsigned long birth, gen_start; + long delta =3D 0; + + gen =3D lru_gen_from_seq(seq); + + for (zone =3D 0; zone < MAX_NR_ZONES; zone++) { + long nr_pages =3D walk->nr_pages[gen][type][zone]; + + if (nr_pages < 0) + delta +=3D -nr_pages; + } + + birth =3D READ_ONCE(lrugen->timestamps[gen]); + next_gen =3D lru_gen_from_seq(seq + 1); + gen_start =3D READ_ONCE(lrugen->timestamps[next_gen]); + + /* ensure gen_start is within idle_age of bin */ + while (bin->idle_age !=3D -1 && + time_before(gen_start + bin->idle_age, + curr_timestamp)) + bin++; + + error =3D delta; + /* gen exceeds the idle_age of bin */ + while (bin->idle_age !=3D -1 && + time_before(birth + bin->idle_age, + curr_timestamp)) { + unsigned long proportion =3D + gen_start - + (curr_timestamp - bin->idle_age); + unsigned long gen_len =3D gen_start - birth; + + if (!gen_len) + break; + if (proportion) { + unsigned long split_bin =3D + delta / gen_len * proportion; + bin->nr_pages[type] +=3D split_bin; + error -=3D split_bin; + } + gen_start =3D curr_timestamp - bin->idle_age; + bin++; + } + bin->nr_pages[type] +=3D error; + } + } +} + +static void collect_reaccess(struct wsr *wsr, + struct lru_gen_struct *lrugen, + struct lru_gen_mm_walk *walk) +{ + if (READ_ONCE(wsr->reaccess_bins->idle_age) =3D=3D -1) + return; + + mutex_lock(&wsr->reaccess_bins_lock); + collect_reaccess_locked(wsr, lrugen, walk); + mutex_unlock(&wsr->reaccess_bins_lock); +} + +void report_reaccess(struct lruvec *lruvec, struct lru_gen_mm_walk *walk) +{ + struct lru_gen_struct *lrugen =3D &lruvec->lrugen; + struct mem_cgroup *memcg =3D lruvec_memcg(lruvec); + + while (memcg) { + collect_reaccess(lruvec_wsr(mem_cgroup_lruvec( + memcg, lruvec_pgdat(lruvec))), + lrugen, walk); + memcg =3D parent_mem_cgroup(memcg); + } +} + static struct pglist_data *kobj_to_pgdat(struct kobject *kobj) { int nid =3D IS_ENABLED(CONFIG_NUMA) ? kobj_to_dev(kobj)->id : --=20 2.41.0.162.gfafddb0af9-goog