From: Eric Sandeen Subject: Re: Documenting MS_LAZYTIME Date: Fri, 20 Feb 2015 09:49:34 -0600 Message-ID: <54E7578E.4090809@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Ext4 Developers List , Linux btrfs Developers List , XFS Developers , linux-man@vger.kernel.org, Linux-Fsdevel , Linux API To: Michael Kerrisk , "Theodore Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46503 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751870AbbBTPto (ORCPT ); Fri, 20 Feb 2015 10:49:44 -0500 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On 2/20/15 2:50 AM, Michael Kerrisk wrote: > Hello Ted, >=20 > Based on your commit message 0ae45f63d4e, I I wrote the documentation > below for MS_LAZYTIME, to go into the mount(2) man page. Could you > please check it over and let me know if it's accurate. In particular, > I added pieces marked with "*" below that were not part of the commit > message and I'd like confirmation that they're accurate. >=20 > Thanks, >=20 > Michael >=20 > [[ > MS_LAZYTIME (since Linux 3.20) > Only update filetimes (atime, mtime, ctime) on the in= - > memory version of the file inode. The on-disk time= =E2=80=90 > stamps are updated only when: "filetimes" and "file inode" seems a bit awkward. How about: > MS_LAZYTIME (since Linux 3.20) > Reduce on-disk updates of inode timestamps (atime, mtime, ctime) > by maintaining these changes only in memory, unless: (maybe I'm bike-shedding too much, if so, sorry). > (a) the inode needs to be updated for some change unre= =E2=80=90 > lated to file timestamps; >=20 > (b) the application employs fsync(2), syncfs(2), o= r > sync(2); >=20 > (c) an undeleted inode is evicted from memory; or >=20 > * (d) more than 24 hours have passed since the i-node wa= s > * written to disk. Please don't use "i-node" - simply "inode" is much more common in the m= anpages AFAICT. > This mount option significantly reduces writes to th= e > inode table for workloads that perform frequent rando= m > 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. -Eric =20 > * As at Linux 3.20, this option is supported only on ext4= =2E > ]] >=20 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html