From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id E33766B0007 for ; Fri, 15 Jun 2018 03:05:01 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id 76-v6so748577wmw.3 for ; Fri, 15 Jun 2018 00:05:01 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 92-v6si3282976edh.423.2018.06.15.00.05.00 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 15 Jun 2018 00:05:00 -0700 (PDT) Subject: Re: [PATCH] doc: add description to dirtytime_expire_seconds References: <1527724613-17768-1-git-send-email-yang.shi@linux.alibaba.com> From: Nikolay Borisov Message-ID: <5a1efc1b-c586-616f-1668-b4b8f24f873a@suse.com> Date: Fri, 15 Jun 2018 10:04:57 +0300 MIME-Version: 1.0 In-Reply-To: <1527724613-17768-1-git-send-email-yang.shi@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Yang Shi , tytso@mit.edu, corbet@lwn.net, akpm@linux-foundation.org Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On 31.05.2018 02:56, Yang Shi wrote: > 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 The second part of this sentence, after the comma doesn't parse. > +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. I think the final sentence is a bit redundant, given the very explicit name of the knob. > + > +============================================================== > + > dirty_writeback_centisecs > > The kernel flusher threads will periodically wake up and write `old' data >