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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 05977C47247 for ; Fri, 8 May 2020 07:25:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CCD3F20736 for ; Fri, 8 May 2020 07:25:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CCD3F20736 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 76F02900005; Fri, 8 May 2020 03:25:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7476B900002; Fri, 8 May 2020 03:25:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 65DD2900005; Fri, 8 May 2020 03:25:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0159.hostedemail.com [216.40.44.159]) by kanga.kvack.org (Postfix) with ESMTP id 4609C900002 for ; Fri, 8 May 2020 03:25:32 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 0DBD44995E3 for ; Fri, 8 May 2020 07:25:32 +0000 (UTC) X-FDA: 76792716504.23.lead87_6a4f2ae6edb16 X-HE-Tag: lead87_6a4f2ae6edb16 X-Filterd-Recvd-Size: 2709 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Fri, 8 May 2020 07:25:30 +0000 (UTC) IronPort-SDR: QlHmQIgtGyHByp5btHqZhTZ/fT0FTavaAShfLS1hkqUqE7nOpg0sbWVBb6UVyRn2CJc8vdxzv7 WEDrODdj0gOA== 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 00:25:30 -0700 IronPort-SDR: XTxoPgiIpK+yKm21wvSPK3ZDNzwkPuJQf+V+gxo+7RrjNFtdNo8zJdE2Rt+Y3Xk+SDBDr0k++H 2sAn7N1ZXtdw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,366,1583222400"; d="scan'208";a="264210556" Received: from shbuild999.sh.intel.com ([10.239.147.136]) by orsmga006.jf.intel.com with ESMTP; 08 May 2020 00:25:26 -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 2/3] mm/util.c: make vm_memory_committed() more accurate Date: Fri, 8 May 2020 15:25:16 +0800 Message-Id: <1588922717-63697-3-git-send-email-feng.tang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1588922717-63697-1-git-send-email-feng.tang@intel.com> References: <1588922717-63697-1-git-send-email-feng.tang@intel.com> 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. Its time cost is about 800 nanoseconds on a 2C/4T platform and 2~3 microseconds on a 2S/36C/72T 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 sever, which should be fine for its two users: /proc/meminfo and HV ballon driver's status trace per second. Signed-off-by: Feng Tang --- mm/util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/util.c b/mm/util.c index 988d11e..3de78e9 100644 --- a/mm/util.c +++ b/mm/util.c @@ -774,7 +774,7 @@ struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; */ 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); -- 2.7.4