From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 9B86F6B0005 for ; Thu, 14 Jun 2018 20:23:48 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id x17-v6so3743201pfm.18 for ; Thu, 14 Jun 2018 17:23:48 -0700 (PDT) Received: from out4437.biz.mail.alibaba.com (out4437.biz.mail.alibaba.com. [47.88.44.37]) by mx.google.com with ESMTPS id 29-v6si6455734pfs.40.2018.06.14.17.23.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 14 Jun 2018 17:23:45 -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: Yang Shi Message-ID: Date: Thu, 14 Jun 2018 17:23:25 -0700 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; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: 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 ping Ted, Any comment is appreciated. Regards, Yang On 5/30/18 4:56 PM, 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 > +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