From: "Michael Kerrisk (man-pages)" Subject: Re: Documenting MS_LAZYTIME Date: Thu, 26 Feb 2015 09:49:39 +0100 Message-ID: <54EEDE23.6080009@gmail.com> References: <54E7578E.4090809@redhat.com> <20150221025636.GB7922@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Ext4 Developers List , Linux btrfs Developers List , XFS Developers , linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux-Fsdevel , Linux API To: Theodore Ts'o , Eric Sandeen Return-path: In-Reply-To: <20150221025636.GB7922-AKGzg7BKzIDYtjvyW6yDsg@public.gmane.org> Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org 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/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html