From patchwork Tue Feb 18 08:26:34 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Ying" X-Patchwork-Id: 11387995 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5D2A11580 for ; Tue, 18 Feb 2020 08:27:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1E1172465A for ; Tue, 18 Feb 2020 08:27:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E1172465A 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 B80BD6B0032; Tue, 18 Feb 2020 03:27:42 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id B32D36B0036; Tue, 18 Feb 2020 03:27:42 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6F8A6B0037; Tue, 18 Feb 2020 03:27:42 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0089.hostedemail.com [216.40.44.89]) by kanga.kvack.org (Postfix) with ESMTP id 9031D6B0032 for ; Tue, 18 Feb 2020 03:27:42 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 2D44C4995F7 for ; Tue, 18 Feb 2020 08:27:42 +0000 (UTC) X-FDA: 76502569164.18.brush19_432b12b982034 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,ying.huang@intel.com,:peterz@infradead.org:mingo@kernel.org::linux-kernel@vger.kernel.org:feng.tang@intel.com:ying.huang@intel.com:akpm@linux-foundation.org:mhocko@suse.com:riel@redhat.com:mgorman@suse.de:dave.hansen@linux.intel.com:dan.j.williams@intel.com,RULES_HIT:30003:30034:30054:30055:30064:30070,0,RBL:134.134.136.100:@intel.com:.lbl8.mailshell.net-62.18.0.100 64.95.201.95,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:24,LUA_SUMMARY:none X-HE-Tag: brush19_432b12b982034 X-Filterd-Recvd-Size: 6976 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Tue, 18 Feb 2020 08:27:41 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Feb 2020 00:27:41 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,455,1574150400"; d="scan'208";a="235466738" Received: from yhuang-dev.sh.intel.com ([10.239.159.151]) by orsmga003.jf.intel.com with ESMTP; 18 Feb 2020 00:27:38 -0800 From: "Huang, Ying" To: Peter Zijlstra , Ingo Molnar Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Feng Tang , Huang Ying , Andrew Morton , Michal Hocko , Rik van Riel , Mel Gorman , Dave Hansen , Dan Williams Subject: [RFC -V2 8/8] autonuma, memory tiering: Adjust hot threshold automatically Date: Tue, 18 Feb 2020 16:26:34 +0800 Message-Id: <20200218082634.1596727-9-ying.huang@intel.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200218082634.1596727-1-ying.huang@intel.com> References: <20200218082634.1596727-1-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: From: Huang Ying 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, that is, the page is the candidate promotion page. If the number of the candidate promotion pages in the statistics interval is much higher than the promotion rate limit, the hot threshold will be lowered to reduce the number of the candidate promotion pages. Otherwise, the hot threshold will be raised 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 autonuma, but the hot/cold distribution isn't uniform along the address. The statistics interval should be larger than the autonuma 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 5.5% with 24.6% 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 6e7a28becdc2..4ed82eb5c8b5 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -792,6 +792,9 @@ typedef struct pglist_data { #ifdef CONFIG_NUMA_BALANCING unsigned long numa_ts; unsigned long numa_try; + unsigned long numa_threshold_ts; + unsigned long numa_threshold_try; + 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 e5f7f4139c82..90098c35d336 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1487,6 +1487,35 @@ 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 try, ref_try, tdiff; + + 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_try = rate_limit * + sysctl_numa_balancing_scan_period_max / 1000; + try = node_page_state(pgdat, NUMA_TRY_MIGRATE); + tdiff = try - pgdat->numa_threshold_try; + unit_th = ref_th / NUMA_MIGRATION_ADJUST_STEPS; + th = pgdat->numa_threshold ? : ref_th; + if (tdiff > ref_try * 11 / 10) + th = max(th - unit_th, unit_th); + else if (tdiff < ref_try * 9 / 10) + th = min(th + unit_th, ref_th); + pgdat->numa_threshold_try = try; + pgdat->numa_threshold = th; + } +} + bool should_numa_migrate_memory(struct task_struct *p, struct page * page, int src_nid, int dst_cpu, unsigned long addr, int flags) @@ -1502,7 +1531,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && next_promotion_node(src_nid) != -1) { 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)) @@ -1512,15 +1541,18 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, if (!(flags & TNF_YOUNG)) return false; - th = msecs_to_jiffies(sysctl_numa_balancing_hot_threshold); + def_th = msecs_to_jiffies(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; if (flags & TNF_WRITE) th *= 2; latency = numa_hint_fault_latency(p, addr); if (latency > th) return false; - rate_limit = - sysctl_numa_balancing_rate_limit << (20 - PAGE_SHIFT); return numa_migration_check_rate_limit(pgdat, rate_limit, hpage_nr_pages(page)); }