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=ham 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 4BDFEC38A2A for ; Fri, 8 May 2020 07:25:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3629C20736 for ; Fri, 8 May 2020 07:25:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727783AbgEHHZb (ORCPT ); Fri, 8 May 2020 03:25:31 -0400 Received: from mga18.intel.com ([134.134.136.126]:27650 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726036AbgEHHZa (ORCPT ); Fri, 8 May 2020 03:25:30 -0400 IronPort-SDR: lCM4wIeHs/QpHKqMdjRWqaMYhrkc1x6yyEnJ3MqkWx/8qYhJ2SfV9EsS7qkRor6uJAwJCHw3ja ab8bmSJklF6g== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga106.jf.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> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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