From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (Postfix) with ESMTP id 02BDB7F47 for ; Thu, 26 Feb 2015 02:50:14 -0600 (CST) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay3.corp.sgi.com (Postfix) with ESMTP id 8B7B1AC009 for ; Thu, 26 Feb 2015 00:50:13 -0800 (PST) Received: from mail-wi0-f174.google.com (mail-wi0-f174.google.com [209.85.212.174]) by cuda.sgi.com with ESMTP id RMBYRNLCjt59e2ar (version=TLSv1 cipher=RC4-SHA bits=128 verify=NO) for ; Thu, 26 Feb 2015 00:49:42 -0800 (PST) Received: by mail-wi0-f174.google.com with SMTP id em10so39197657wid.1 for ; Thu, 26 Feb 2015 00:49:41 -0800 (PST) Message-ID: <54EEDE23.6080009@gmail.com> Date: Thu, 26 Feb 2015 09:49:39 +0100 From: "Michael Kerrisk (man-pages)" MIME-Version: 1.0 Subject: Re: Documenting MS_LAZYTIME References: <54E7578E.4090809@redhat.com> <20150221025636.GB7922@thunk.org> In-Reply-To: <20150221025636.GB7922@thunk.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Theodore Ts'o , Eric Sandeen Cc: linux-man@vger.kernel.org, Linux API , XFS Developers , mtk.manpages@gmail.com, Linux-Fsdevel , Ext4 Developers List , Linux btrfs Developers List Ted, On 02/21/2015 03:56 AM, Theodore Ts'o wrote: > On Fri, Feb 20, 2015 at 09:49:34AM -0600, Eric Sandeen wrote: >> >>> This mount option significantly reduces writes to the >>> inode table for workloads that perform frequent random >>> writes to preallocated files. >> >> This seems like an overly specific description of a single workload out >> of many which may benefit, but what do others think? "inode table" is also >> fairly extN-specific. > > How about somethign like "This mount significantly reduces writes > needed to update the inode's timestamps, especially mtime and actime. What is "actime" in the preceding line? Should it be "ctime"? > Examples of workloads where this could be a large win include frequent > random writes to preallocated files, as well as cases where the > MS_STRICTATIME mount option is enabled."? I think some version of the following text could also usefully go into the page, but... > (The advantage of MS_STRICTATIME | MS_LAZYTIME is that stat system > calls will return the correctly updated atime, but those atime updates > won't get flushed to disk unless the inode needs to be updated for > file system / data consistency reasons, or when the inode is pushed > out of memory, or when the file system is unmounted.) I find the wording of there a little confusing. Is the following a correct rewrite: The advantage of MS_STRICTATIME | MS_LAZYTIME is that stat(2) will return the correctly updated atime, but the atime updates will be flushed to disk only when (1) the inode needs to be updated for filesystem / data consistency reasons or (2) the inode is pushed out of memory, or (3) the filesystem is unmounted.) ? Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs