From patchwork Sat May 16 06:47:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Feng Tang X-Patchwork-Id: 11553341 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 8B132913 for ; Sat, 16 May 2020 06:47:48 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 630762065C for ; Sat, 16 May 2020 06:47:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 630762065C 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 4ECAD8E0003; Sat, 16 May 2020 02:47:47 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 49D668E0001; Sat, 16 May 2020 02:47:47 -0400 (EDT) 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 38B6F8E0003; Sat, 16 May 2020 02:47:47 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0188.hostedemail.com [216.40.44.188]) by kanga.kvack.org (Postfix) with ESMTP id 1E9448E0001 for ; Sat, 16 May 2020 02:47:47 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id C4C802492 for ; Sat, 16 May 2020 06:47:46 +0000 (UTC) X-FDA: 76821651732.28.help08_60de0e35fc41d X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,feng.tang@intel.com,,RULES_HIT:30003:30012:30034:30054:30064:30070,0,RBL:192.55.52.151:@intel.com:.lbl8.mailshell.net-64.95.201.95 62.18.0.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:ft,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:23,LUA_SUMMARY:none X-HE-Tag: help08_60de0e35fc41d X-Filterd-Recvd-Size: 4348 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Sat, 16 May 2020 06:47:45 +0000 (UTC) IronPort-SDR: I4bJM2EClrd+F5f0a+FQu7H83YVshp5upbef4qqXTve8mL/9QEkivd1mBqBHEVfucij7ASVYr8 DcX/t0NumlMQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 May 2020 23:47:44 -0700 IronPort-SDR: 4mIIABA26zylbkkwoCiiMNX7ixGCSArWEWULx0/ShWNRQWleiQuk1oghQxLFw7xONW0+w04E55 AV/fIpwuG5kg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,398,1583222400"; d="scan'208";a="464984919" Received: from shbuild999.sh.intel.com ([10.239.146.107]) by fmsmga005.fm.intel.com with ESMTP; 15 May 2020 23:47:41 -0700 From: Feng Tang To: Andrew Morton , Michal Hocko , Matthew Wilcox , Johannes Weiner , Mel Gorman , Kees Cook , andi.kleen@intel.com, tim.c.chen@intel.com, dave.hansen@intel.com, ying.huang@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Feng Tang Subject: [PATCH v3 0/3] make vm_committed_as_batch aware of vm overcommit policy Date: Sat, 16 May 2020 14:47:37 +0800 Message-Id: <1589611660-89854-1-git-send-email-feng.tang@intel.com> X-Mailer: git-send-email 2.7.4 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: When checking a performance change for will-it-scale scalability mmap test [1], we found very high lock contention for spinlock of percpu counter 'vm_committed_as': 94.14% 0.35% [kernel.kallsyms] [k] _raw_spin_lock_irqsave 48.21% _raw_spin_lock_irqsave;percpu_counter_add_batch;__vm_enough_memory;mmap_region;do_mmap; 45.91% _raw_spin_lock_irqsave;percpu_counter_add_batch;__do_munmap; Actually this heavy lock contention is not always necessary. The 'vm_committed_as' needs to be very precise when the strict OVERCOMMIT_NEVER policy is set, which requires a rather small batch number for the percpu counter. So keep 'batch' number unchanged for strict OVERCOMMIT_NEVER policy, and enlarge it for not-so-strict OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS policies. Benchmark with the same testcase in [1] shows 53% improvement on a 8C/16T desktop, and 2097%(20X) on a 4S/72C/144T server. And for that case, whether it shows improvements depends on if the test mmap size is bigger than the batch number computed. We tested 10+ platforms in 0day (server, desktop and laptop). If we lift it to 64X, 80%+ platforms show improvements, and for 16X lift, 1/3 of the platforms will show improvements. And generally it should help the mmap/unmap usage,as Michal Hocko mentioned: " I believe that there are non-synthetic worklaods which would benefit from a larger batch. E.g. large in memory databases which do large mmaps during startups from multiple threads. " Note: There are some style complain from checkpatch for patch 3, as sysctl handler declaration follows the similar format of sibling functions patch1: a cleanup for /proc/meminfo patch2: a preparation patch which also improve the accuracy of vm_memory_committed patch3: the main change Please help to review, thanks! - Feng ---------------------------------------------------------------- Changelog: v3: * refine commit log and cleanup code, according to comments from Michal Hocko and Matthew Wilcox * change the lift from 16X and 64X after test v2: * add the sysctl handler to cover runtime overcommit policy change, as suggested by Andres Morton * address the accuracy concern of vm_memory_committed() from Andi Kleen Feng Tang (3): proc/meminfo: avoid open coded reading of vm_committed_as mm/util.c: make vm_memory_committed() more accurate mm: adjust vm_committed_as_batch according to vm overcommit policy fs/proc/meminfo.c | 2 +- include/linux/mm.h | 2 ++ include/linux/mman.h | 4 ++++ kernel/sysctl.c | 2 +- mm/mm_init.c | 18 ++++++++++++++---- mm/util.c | 15 ++++++++++++++- 6 files changed, 36 insertions(+), 7 deletions(-)