From patchwork Fri Jul 10 14:01:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Feng Tang X-Patchwork-Id: 11656733 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 7265C13B6 for ; Fri, 10 Jul 2020 14:03:46 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 47712207BB for ; Fri, 10 Jul 2020 14:03:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 47712207BB 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 DFE1B8D0009; Fri, 10 Jul 2020 10:03:43 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id DDF358D0006; Fri, 10 Jul 2020 10:03:43 -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 CC3E68D0009; Fri, 10 Jul 2020 10:03:43 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0160.hostedemail.com [216.40.44.160]) by kanga.kvack.org (Postfix) with ESMTP id B5A8F8D0006 for ; Fri, 10 Jul 2020 10:03:43 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 68C67613B for ; Fri, 10 Jul 2020 14:03:43 +0000 (UTC) X-FDA: 77022334326.01.space17_041721926ece Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id CF13B1000A7E42D0 for ; Fri, 10 Jul 2020 14:02:17 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,feng.tang@intel.com,,RULES_HIT:30046:30054:30064:30075,0,RBL:134.134.136.65:@intel.com:.lbl8.mailshell.net-64.95.201.95 62.18.0.100;04yfa51ndixri386xrxa4ihaz478nycnn4s16814mf8zzu9zbtapa5f3tzmhf5e.bndd9hp737wsy69xnjy4ssb1jefznytgqbmj7qcj3tspecj1mie56f95wakh6bi.6-lbl8.mailshell.net-223.238.255.100,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:24,LUA_SUMMARY:none X-HE-Tag: space17_041721926ece X-Filterd-Recvd-Size: 4175 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Fri, 10 Jul 2020 14:02:16 +0000 (UTC) IronPort-SDR: nyw4Zy3aqPBNP3h0sLXYpwJXRzvtbXCq9nO0X62S0NmoSlOPRyRwtZNhxW1Ii731jlUAXLwSzW onzi/dmZUigQ== X-IronPort-AV: E=McAfee;i="6000,8403,9677"; a="148188204" X-IronPort-AV: E=Sophos;i="5.75,336,1589266800"; d="scan'208";a="148188204" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jul 2020 07:02:00 -0700 IronPort-SDR: OTQC5lfVS8VaF2w6vI2VH1bmljaJYefPE78XlTvQ3xquRSU5Kz2DpvaNSN/jZt0WomWhfZIYKA vLS/stXmdl3Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,336,1589266800"; d="scan'208";a="458287130" Received: from shbuild999.sh.intel.com ([10.239.146.107]) by orsmga005.jf.intel.com with ESMTP; 10 Jul 2020 07:01:56 -0700 From: Feng Tang To: Andrew Morton , Michal Hocko , Johannes Weiner , Matthew Wilcox , Mel Gorman , Kees Cook , Qian Cai , Dennis Zhou , 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 , "K. Y. Srinivasan" , Haiyang Zhang Subject: [PATCH v6 2/4] mm/util.c: make vm_memory_committed() more accurate Date: Fri, 10 Jul 2020 22:01:46 +0800 Message-Id: <1594389708-60781-3-git-send-email-feng.tang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1594389708-60781-1-git-send-email-feng.tang@intel.com> References: <1594389708-60781-1-git-send-email-feng.tang@intel.com> X-Rspamd-Queue-Id: CF13B1000A7E42D0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 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: percpu_counter_sum_positive() will provide more accurate info. As with percpu_counter_read_positive(), in worst case the deviation could be 'batch * nr_cpus', which is totalram_pages/256 for now, and will be more when the batch gets enlarged. Its time cost is about 800 nanoseconds on a 2C/4T platform and 2~3 microseconds on a 2S/36C/72T Skylake server in normal case, and in worst case where vm_committed_as's spinlock is under severe contention, it costs 30~40 microseconds for the 2S/36C/72T Skylake sever, which should be fine for its only two users: /proc/meminfo and HyperV balloon driver's status trace per second. Link: http://lkml.kernel.org/r/1592725000-73486-3-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang Acked-by: Michal Hocko # for /proc/meminfo Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Matthew Wilcox (Oracle) Cc: Johannes Weiner Cc: Mel Gorman Cc: Qian Cai Cc: Andi Kleen Cc: Tim Chen Cc: Dave Hansen Cc: Huang Ying Signed-off-by: Andrew Morton --- mm/util.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/util.c b/mm/util.c index c856f5f..d076218 100644 --- a/mm/util.c +++ b/mm/util.c @@ -787,10 +787,15 @@ struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; * balancing memory across competing virtual machines that are hosted. * Several metrics drive this policy engine including the guest reported * memory commitment. + * + * The time cost of this is very low for small platforms, and for big + * platform like a 2S/36C/72T Skylake server, in worst case where + * vm_committed_as's spinlock is under severe contention, the time cost + * could be about 30~40 microseconds. */ unsigned long vm_memory_committed(void) { - return percpu_counter_read_positive(&vm_committed_as); + return percpu_counter_sum_positive(&vm_committed_as); } EXPORT_SYMBOL_GPL(vm_memory_committed);