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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY 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 E9E4CC5AE59 for ; Mon, 18 Jun 2018 23:59:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A0C3A20671 for ; Mon, 18 Jun 2018 23:59:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A0C3A20671 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937104AbeFRX7o (ORCPT ); Mon, 18 Jun 2018 19:59:44 -0400 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:49085 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936119AbeFRX7m (ORCPT ); Mon, 18 Jun 2018 19:59:42 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R391e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04452;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0T2yK.Jw_1529366358; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0T2yK.Jw_1529366358) by smtp.aliyun-inc.com(127.0.0.1); Tue, 19 Jun 2018 07:59:24 +0800 From: Yang Shi To: tytso@mit.edu, nborisov@suse.com, corbet@lwn.net, akpm@linux-foundation.org Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] doc: add description to dirtytime_expire_seconds Date: Tue, 19 Jun 2018 07:59:18 +0800 Message-Id: <1529366358-67312-1-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit 1efff914afac8a965ad63817ecf8861a927c2ace ("fs: add dirtytime_expire_seconds sysctl") introduced dirtytime_expire_seconds knob, but there is not description about it in Documentation/sysctl/vm.txt. Add the description for it. Cc: Theodore Ts'o Signed-off-by: Yang Shi --- v1 --> v2: Rephrased the description per Nikolay Borisov's comment I didn't dig into the old review discussion about why the description was not added at the first place. I'm supposed every knob under /proc/sys should have a brief description. Documentation/sysctl/vm.txt | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 17256f2..b078baf 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm: - dirty_bytes - dirty_expire_centisecs - dirty_ratio +- dirtytime_expire_seconds - dirty_writeback_centisecs - drop_caches - extfrag_threshold @@ -178,6 +179,18 @@ The total available memory is not equal to total system memory. ============================================================== +dirtytime_expire_seconds + +When a lazytime inode is constantly having its pages dirtied, the inode with +an updated timestamp will never get chance to be written out. And, if the +only thing that has happened on the file system is a dirtytime inode caused +by an atime update, a worker will be scheduled to make sure that inode +eventually gets pushed out to disk. This tunable is used to define when dirty +inode is old enough to be eligible for writeback by the kernel flusher threads. +And, it is also used as the interval to wakeup dirtytime_writeback thread. + +============================================================== + dirty_writeback_centisecs The kernel flusher threads will periodically wake up and write `old' data -- 1.8.3.1