From patchwork Wed May 30 23:56:53 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yang Shi X-Patchwork-Id: 10440093 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 4DE1C60327 for ; Wed, 30 May 2018 23:57:13 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3FCCB29302 for ; Wed, 30 May 2018 23:57:13 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 32FE82940E; Wed, 30 May 2018 23:57:13 +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=ham 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 3436C29302 for ; Wed, 30 May 2018 23:57:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932570AbeE3X5H (ORCPT ); Wed, 30 May 2018 19:57:07 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:59784 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932091AbeE3X5G (ORCPT ); Wed, 30 May 2018 19:57:06 -0400 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R131e4; CH=green; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e07487; MF=yang.shi@linux.alibaba.com; NM=1; PH=DS; RN=7; SR=0; TI=SMTPD_---0T1uApIh_1527724613; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0T1uApIh_1527724613) by smtp.aliyun-inc.com(127.0.0.1); Thu, 31 May 2018 07:57:00 +0800 From: Yang Shi To: tytso@mit.edu, corbet@lwn.net, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] doc: add description to dirtytime_expire_seconds Date: Thu, 31 May 2018 07:56:53 +0800 Message-Id: <1527724613-17768-1-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 --- 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 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 17256f2..f4f4f9c 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 +179,16 @@ The total available memory is not equal to total system memory. ============================================================== +dirtytime_expire_seconds + +When a lazytime inode is constantly having its pages dirtied, it with an +updated timestamp will never get chance to be written out. 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. It is expressed in seconds. + +============================================================== + dirty_writeback_centisecs The kernel flusher threads will periodically wake up and write `old' data