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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 C2948C07E9D for ; Thu, 22 Jul 2021 03:19:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC22061001 for ; Thu, 22 Jul 2021 03:19:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231252AbhGVCis (ORCPT ); Wed, 21 Jul 2021 22:38:48 -0400 Received: from mga12.intel.com ([192.55.52.136]:47198 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231174AbhGVCib (ORCPT ); Wed, 21 Jul 2021 22:38:31 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10052"; a="191139220" X-IronPort-AV: E=Sophos;i="5.84,259,1620716400"; d="scan'208";a="191139220" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jul 2021 20:19:07 -0700 X-IronPort-AV: E=Sophos;i="5.84,259,1620716400"; d="scan'208";a="501577023" Received: from yhuang6-desk2.sh.intel.com ([10.239.159.119]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Jul 2021 20:19:04 -0700 From: Huang Ying To: linux-kernel@vger.kernel.org Cc: Huang Ying , Andrew Morton , Michal Hocko , Rik van Riel , Mel Gorman , Peter Zijlstra , Dave Hansen , Yang Shi , Zi Yan , Wei Xu , osalvador , Shakeel Butt , linux-mm@kvack.org Subject: [PATCH -V7 5/6] memory tiering: rate limit NUMA migration throughput Date: Thu, 22 Jul 2021 11:18:18 +0800 Message-Id: <20210722031819.3446711-6-ying.huang@intel.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210722031819.3446711-1-ying.huang@intel.com> References: <20210722031819.3446711-1-ying.huang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In NUMA balancing memory tiering mode, the hot slow memory pages could be promoted to the fast memory node via NUMA balancing. But this incurs some overhead too. So that sometimes the workload performance may be hurt. To avoid too much disturbing to the workload in these situations, we should make it possible to rate limit the promotion throughput. So, in this patch, we implement a simple rate limit algorithm as follows. The number of the candidate pages to be promoted to the fast memory node via NUMA balancing is counted, if the count exceeds the limit specified by the users, the NUMA balancing promotion will be stopped until the next second. Test the patch with the pmbench memory accessing benchmark with 80:20 read/write ratio and normal access address distribution on a 2 socket Intel server with Optane DC Persistent Memory Model. In the test, the page promotion throughput decreases 51.4% (from 213.0 MB/s to 103.6 MB/s) with the patch, while the benchmark score decreases only 1.8%. A new sysctl knob kernel.numa_balancing_rate_limit_mbps is added for the users to specify the limit. TODO: Add ABI document for new sysctl knob. Signed-off-by: "Huang, Ying" Cc: Andrew Morton Cc: Michal Hocko Cc: Rik van Riel Cc: Mel Gorman Cc: Peter Zijlstra Cc: Dave Hansen Cc: Yang Shi Cc: Zi Yan Cc: Wei Xu Cc: osalvador Cc: Shakeel Butt Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org --- include/linux/mmzone.h | 5 +++++ include/linux/sched/sysctl.h | 1 + kernel/sched/fair.c | 29 +++++++++++++++++++++++++++-- kernel/sysctl.c | 8 ++++++++ mm/vmstat.c | 1 + 5 files changed, 42 insertions(+), 2 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 6c1ffc7bf5a4..c71beb262c44 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -212,6 +212,7 @@ enum node_stat_item { #endif #ifdef CONFIG_NUMA_BALANCING PGPROMOTE_SUCCESS, /* promote successfully */ + PGPROMOTE_CANDIDATE, /* candidate pages to promote */ #endif NR_VM_NODE_STAT_ITEMS }; @@ -879,6 +880,10 @@ typedef struct pglist_data { struct deferred_split deferred_split_queue; #endif +#ifdef CONFIG_NUMA_BALANCING + unsigned long numa_ts; + unsigned long numa_nr_candidate; +#endif /* Fields commonly accessed by the page reclaim scanner */ /* diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index 0ea43b146aee..7d937adaac0f 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -42,6 +42,7 @@ enum sched_tunable_scaling { #ifdef CONFIG_NUMA_BALANCING extern int sysctl_numa_balancing_mode; extern unsigned int sysctl_numa_balancing_hot_threshold; +extern unsigned int sysctl_numa_balancing_rate_limit; #else #define sysctl_numa_balancing_mode 0 #endif diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 98e3f1600ca6..d4ce77cc22d3 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1039,6 +1039,11 @@ unsigned int sysctl_numa_balancing_scan_delay = 1000; /* The page with hint page fault latency < threshold in ms is considered hot */ unsigned int sysctl_numa_balancing_hot_threshold = 1000; +/* + * Restrict the NUMA migration per second in MB for each target node + * if no enough free space in target node + */ +unsigned int sysctl_numa_balancing_rate_limit = 65536; struct numa_group { refcount_t refcount; @@ -1411,6 +1416,23 @@ static int numa_hint_fault_latency(struct page *page) return (time - last_time) & PAGE_ACCESS_TIME_MASK; } +static bool numa_migration_check_rate_limit(struct pglist_data *pgdat, + unsigned long rate_limit, int nr) +{ + unsigned long nr_candidate; + unsigned long now = jiffies, last_ts; + + mod_node_page_state(pgdat, PGPROMOTE_CANDIDATE, nr); + nr_candidate = node_page_state(pgdat, PGPROMOTE_CANDIDATE); + last_ts = pgdat->numa_ts; + if (now > last_ts + HZ && + cmpxchg(&pgdat->numa_ts, last_ts, now) == last_ts) + pgdat->numa_nr_candidate = nr_candidate; + if (nr_candidate - pgdat->numa_nr_candidate > rate_limit) + return false; + return true; +} + bool should_numa_migrate_memory(struct task_struct *p, struct page * page, int src_nid, int dst_cpu) { @@ -1425,7 +1447,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && !node_is_toptier(src_nid)) { struct pglist_data *pgdat; - unsigned long latency, th; + unsigned long rate_limit, latency, th; pgdat = NODE_DATA(dst_nid); if (pgdat_free_space_enough(pgdat)) @@ -1436,7 +1458,10 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, if (latency > th) return false; - return true; + rate_limit = + sysctl_numa_balancing_rate_limit << (20 - PAGE_SHIFT); + return numa_migration_check_rate_limit(pgdat, rate_limit, + thp_nr_pages(page)); } this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 27b6daeb1004..0c7dff728c65 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1777,6 +1777,14 @@ static struct ctl_table kern_table[] = { .mode = 0644, .proc_handler = proc_dointvec, }, + { + .procname = "numa_balancing_rate_limit_mbps", + .data = &sysctl_numa_balancing_rate_limit, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + }, #endif /* CONFIG_NUMA_BALANCING */ { .procname = "sched_rt_period_us", diff --git a/mm/vmstat.c b/mm/vmstat.c index f43eb3813fe7..1a3880ea4bf0 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1190,6 +1190,7 @@ const char * const vmstat_text[] = { #endif #ifdef CONFIG_NUMA_BALANCING "pgpromote_success", + "pgpromote_candidate", #endif /* enum writeback_stat_item counters */ -- 2.30.2