Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751497AbdIOJZA (ORCPT ); Fri, 15 Sep 2017 05:25:00 -0400 Received: from mga04.intel.com ([192.55.52.120]:3719 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453AbdIOJYz (ORCPT ); Fri, 15 Sep 2017 05:24:55 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,396,1500966000"; d="scan'208";a="152182710" From: Kemi Wang To: "Luis R . Rodriguez" , Kees Cook , Andrew Morton , Jonathan Corbet , Michal Hocko , Mel Gorman , Johannes Weiner , Christopher Lameter , Sebastian Andrzej Siewior , Vlastimil Babka , Hillf Danton Cc: Dave , Tim Chen , Andi Kleen , Jesper Dangaard Brouer , Ying Huang , Aaron Lu , Kemi Wang , Proc sysctl , Linux MM , Linux Kernel Subject: [PATCH 3/3] sysctl/vm.txt: Update document Date: Fri, 15 Sep 2017 17:23:26 +0800 Message-Id: <1505467406-9945-4-git-send-email-kemi.wang@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1505467406-9945-1-git-send-email-kemi.wang@intel.com> References: <1505467406-9945-1-git-send-email-kemi.wang@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1894 Lines: 57 Add a paragraph to introduce the functionality and usage on vmstat_mode in sysctl/vm.txt Reported-by: Jesper Dangaard Brouer Suggested-by: Dave Hansen Suggested-by: Ying Huang Signed-off-by: Kemi Wang --- Documentation/sysctl/vm.txt | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 9baf66a..6ab2843 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -61,6 +61,7 @@ Currently, these files are in /proc/sys/vm: - swappiness - user_reserve_kbytes - vfs_cache_pressure +- vmstat_mode - watermark_scale_factor - zone_reclaim_mode @@ -843,6 +844,31 @@ ten times more freeable objects than there are. ============================================================= +vmstat_mode + +This interface allows virtual memory statistics configurable. + +When performance becomes a bottleneck and you can tolerate some possible +tool breakage and some decreased counter precision (e.g. numa counter), you +can do: + echo [C|c]oarse > /proc/sys/vm/vmstat_mode +ignorable statistics list: +- numa counters + +When performance is not a bottleneck and you want all tooling to work, you +can do: + echo [S|s]trict > /proc/sys/vm/vmstat_mode + +We recommend automatic detection of virtual memory statistics by system, +this is also system default configuration, you can do: + echo [A|a]uto > /proc/sys/vm/vmstat_mode + +E.g. numa statistics does not affect system's decision and it is very +rarely consumed. If set vmstat_mode = auto, numa counters update is skipped +unless the counter is *read* by users at least once. + +============================================================== + watermark_scale_factor: This factor controls the aggressiveness of kswapd. It defines the -- 2.7.4