From patchwork Mon Jun 18 23:59:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Shi X-Patchwork-Id: 10472793 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E15D760244 for ; Mon, 18 Jun 2018 23:59:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D287D28AFD for ; Mon, 18 Jun 2018 23:59:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C5C7B28B54; Mon, 18 Jun 2018 23:59:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 697C928AFD for ; Mon, 18 Jun 2018 23:59:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937085AbeFRX7o (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-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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