From patchwork Thu Feb 4 10:10:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Ying" X-Patchwork-Id: 12066733 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=-16.7 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=ham 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 289DAC433E0 for ; Thu, 4 Feb 2021 10:12:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BE0DB64F53 for ; Thu, 4 Feb 2021 10:12:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE0DB64F53 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 427036B0074; Thu, 4 Feb 2021 05:12:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3DC1B6B0075; Thu, 4 Feb 2021 05:12:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2EF7F6B0078; Thu, 4 Feb 2021 05:12:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0113.hostedemail.com [216.40.44.113]) by kanga.kvack.org (Postfix) with ESMTP id 15A1C6B0074 for ; Thu, 4 Feb 2021 05:12:06 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D65CF180AD811 for ; Thu, 4 Feb 2021 10:12:05 +0000 (UTC) X-FDA: 77780169810.02.kiss07_210b8b5275db Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id BDCEA10097AA1 for ; Thu, 4 Feb 2021 10:12:05 +0000 (UTC) X-HE-Tag: kiss07_210b8b5275db X-Filterd-Recvd-Size: 7065 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by imf44.hostedemail.com (Postfix) with ESMTP for ; Thu, 4 Feb 2021 10:12:04 +0000 (UTC) IronPort-SDR: BvybHbkmxtn0QnF6cWbkoXCABOuNxuEpbBReaqBlt/Zz/ZTApUaN1TxFcwK75yzvL9IVUujiGd ZtdteiTHUPWg== X-IronPort-AV: E=McAfee;i="6000,8403,9884"; a="160968999" X-IronPort-AV: E=Sophos;i="5.79,400,1602572400"; d="scan'208";a="160968999" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Feb 2021 02:12:03 -0800 IronPort-SDR: Z/5cScqBNNzzBoL0Z8V9jtCQYzCLTmJrQCGPd23CcQrnzjBzga1gVsaITf6Ds2TODhkUyj/JJW KGPE7FHWIdzQ== X-IronPort-AV: E=Sophos;i="5.79,400,1602572400"; d="scan'208";a="393093510" Received: from qwang9-mobl.ccr.corp.intel.com (HELO yhuang6-mobl1.ccr.corp.intel.com) ([10.254.213.123]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Feb 2021 02:12:01 -0800 From: Huang Ying To: Peter Zijlstra Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Andrew Morton , Michal Hocko , Rik van Riel , Mel Gorman , Ingo Molnar , Dave Hansen , Dan Williams Subject: [RFC -V5 5/6] memory tiering: adjust hot threshold automatically Date: Thu, 4 Feb 2021 18:10:55 +0800 Message-Id: <20210204101056.89336-6-ying.huang@intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210204101056.89336-1-ying.huang@intel.com> References: <20210204101056.89336-1-ying.huang@intel.com> MIME-Version: 1.0 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: It isn't easy for the administrator to determine the hot threshold. So in this patch, a method to adjust the hot threshold automatically is implemented. The basic idea is to control the number of the candidate promotion pages to match the promotion rate limit. If the hint page fault latency of a page is less than the hot threshold, we will try to promote the page, and the page is called the candidate promotion page. If the number of the candidate promotion pages in the statistics interval is much more than the promotion rate limit, the hot threshold will be decreased to reduce the number of the candidate promotion pages. Otherwise, the hot threshold will be increased to increase the number of the candidate promotion pages. To make the above method works, in each statistics interval, the total number of the pages to check (on which the hint page faults occur) and the hot/cold distribution need to be stable. Because the page tables are scanned linearly in NUMA balancing, but the hot/cold distribution isn't uniform along the address, the statistics interval should be larger than the NUMA balancing scan period. So in the patch, the max scan period is used as statistics interval and it works well in our tests. The sysctl knob kernel.numa_balancing_hot_threshold_ms becomes the initial value and max value of the hot threshold. The patch improves the score of pmbench memory accessing benchmark with 80:20 read/write ratio and normal access address distribution by 3.9% with 32.4% fewer NUMA page migrations on a 2 socket Intel server with Optance DC Persistent Memory. Because it improves the accuracy of the hot page selection. Signed-off-by: "Huang, Ying" Cc: Andrew Morton Cc: Michal Hocko Cc: Rik van Riel Cc: Mel Gorman Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Dave Hansen Cc: Dan Williams Cc: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org --- include/linux/mmzone.h | 3 +++ kernel/sched/fair.c | 40 ++++++++++++++++++++++++++++++++++++---- 2 files changed, 39 insertions(+), 4 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 81a67d9cc7db..897331d5e57c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -816,6 +816,9 @@ typedef struct pglist_data { #ifdef CONFIG_NUMA_BALANCING unsigned long numa_ts; unsigned long numa_nr_candidate; + unsigned long numa_threshold_ts; + unsigned long numa_threshold_nr_candidate; + unsigned long numa_threshold; #endif /* Fields commonly accessed by the page reclaim scanner */ diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 18e287997a90..5dcae24a86f6 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1470,6 +1470,35 @@ static bool numa_migration_check_rate_limit(struct pglist_data *pgdat, return true; } +#define NUMA_MIGRATION_ADJUST_STEPS 16 + +static void numa_migration_adjust_threshold(struct pglist_data *pgdat, + unsigned long rate_limit, + unsigned long ref_th) +{ + unsigned long now = jiffies, last_th_ts, th_period; + unsigned long unit_th, th; + unsigned long nr_cand, ref_cand, diff_cand; + + th_period = msecs_to_jiffies(sysctl_numa_balancing_scan_period_max); + last_th_ts = pgdat->numa_threshold_ts; + if (now > last_th_ts + th_period && + cmpxchg(&pgdat->numa_threshold_ts, last_th_ts, now) == last_th_ts) { + ref_cand = rate_limit * + sysctl_numa_balancing_scan_period_max / 1000; + nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE); + diff_cand = nr_cand - pgdat->numa_threshold_nr_candidate; + unit_th = ref_th / NUMA_MIGRATION_ADJUST_STEPS; + th = pgdat->numa_threshold ? : ref_th; + if (diff_cand > ref_cand * 11 / 10) + th = max(th - unit_th, unit_th); + else if (diff_cand < ref_cand * 9 / 10) + th = min(th + unit_th, ref_th); + pgdat->numa_threshold_nr_candidate = nr_cand; + pgdat->numa_threshold = th; + } +} + bool should_numa_migrate_memory(struct task_struct *p, struct page * page, int src_nid, int dst_cpu) { @@ -1484,19 +1513,22 @@ 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 rate_limit, latency, th; + unsigned long rate_limit, latency, th, def_th; pgdat = NODE_DATA(dst_nid); if (pgdat_free_space_enough(pgdat)) return true; - th = sysctl_numa_balancing_hot_threshold; + def_th = sysctl_numa_balancing_hot_threshold; + rate_limit = + sysctl_numa_balancing_rate_limit << (20 - PAGE_SHIFT); + numa_migration_adjust_threshold(pgdat, rate_limit, def_th); + + th = pgdat->numa_threshold ? : def_th; latency = numa_hint_fault_latency(page); if (latency > th) return false; - rate_limit = - sysctl_numa_balancing_rate_limit << (20 - PAGE_SHIFT); return numa_migration_check_rate_limit(pgdat, rate_limit, thp_nr_pages(page)); }