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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no 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 CAAAAC38A2A for ; Fri, 8 May 2020 07:25:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9DDE120736 for ; Fri, 8 May 2020 07:25:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9DDE120736 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 328BA900003; Fri, 8 May 2020 03:25:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 300CC900002; Fri, 8 May 2020 03:25:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 21577900003; Fri, 8 May 2020 03:25:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0055.hostedemail.com [216.40.44.55]) by kanga.kvack.org (Postfix) with ESMTP id 0602E900002 for ; Fri, 8 May 2020 03:25:26 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id ABF68181AEF07 for ; Fri, 8 May 2020 07:25:25 +0000 (UTC) X-FDA: 76792716210.25.jump44_695b20d26c908 X-HE-Tag: jump44_695b20d26c908 X-Filterd-Recvd-Size: 3848 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Fri, 8 May 2020 07:25:23 +0000 (UTC) IronPort-SDR: VavVxXjDyDOKvv7m6ox2N+dY0pkZKJujH2IPIdl3IIw/YPh1mh3F9Kztlbql6kkQlrFx5b9GtU LxENz50aWnsA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2020 00:25:22 -0700 IronPort-SDR: 1UP0CFtipWjgq6gQJZBzzZajBTmR3A4NjdCKdgyxGhXkDCpDK7ixJn3UVKURlKus5kQgvXntPF hyx/BhGficZw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,366,1583222400"; d="scan'208";a="264210525" Received: from shbuild999.sh.intel.com ([10.239.147.136]) by orsmga006.jf.intel.com with ESMTP; 08 May 2020 00:25:18 -0700 From: Feng Tang To: Andrew Morton , Michal Hocko , Johannes Weiner , Matthew Wilcox , Mel Gorman , Kees Cook , Luis Chamberlain , Iurii Zaikin , 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 0/3] make vm_committed_as_batch aware of vm overcommit policy Date: Fri, 8 May 2020 15:25:14 +0800 Message-Id: <1588922717-63697-1-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 lift the batch number to 16X for OVERCOMMIT_ALWAYS and OVERCOMMIT_GUESS policies, and add a sysctl handler to adjust it when the policy is reconfigured. 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 no change for some platforms, due to the test mmap size of the case is bigger than the batch number computed, though the patch will help mmap/munmap generally. [1] https://lkml.org/lkml/2020/3/5/57 There are some style complain from checkpatch for patch 3, as it 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: 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 | 19 +++++++++++++++---- mm/util.c | 15 ++++++++++++++- 6 files changed, 37 insertions(+), 7 deletions(-) -- 2.7.4