From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 975357F73 for ; Tue, 20 May 2014 06:22:10 -0500 (CDT) Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by relay1.corp.sgi.com (Postfix) with ESMTP id 90BE38F8040 for ; Tue, 20 May 2014 04:22:07 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by cuda.sgi.com with ESMTP id SpSZfyv7I0CShVHd for ; Tue, 20 May 2014 04:22:06 -0700 (PDT) Date: Tue, 20 May 2014 07:17:06 -0400 From: Brian Foster Subject: Re: [RFC PATCH 2/2] xfs: sysfs attributes for the current log state Message-ID: <20140520111706.GA3124@laptop.bfoster> References: <1400263966-35541-1-git-send-email-bfoster@redhat.com> <1400263966-35541-3-git-send-email-bfoster@redhat.com> <20140519215658.GD8554@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20140519215658.GD8554@dastard> 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: Dave Chinner Cc: xfs@oss.sgi.com On Tue, May 20, 2014 at 07:56:58AM +1000, Dave Chinner wrote: > On Fri, May 16, 2014 at 02:12:46PM -0400, Brian Foster wrote: > > Create sysfs attributes to export the current runtime state of the log > > to userspace. Note that the filesystem should be frozen for best > > accuracy/consistency when reading these values, but is not required. > > This is for testing and debug purposes only. > > > > Create the following per-mount attributes: log_head_lsn, log_tail_lsn, > > reserve_head_lsn and write_head_lsn. These represent the physical log > > Reserve and write heads are not log sequence numbers (LSNs). A LSN > is a cycle:block count tuple, while a grant head is a cycle:byte > count tuple.... > Yeah, I suppose that's some terminology abuse... ;) > Calling the reserve_grant_head/write_grant_head would make more > sense, I think, as would splitting them into cycle/byte output > pairs. Splitting them make sense because if we increase the log size > beyond 2GB we're going to need a different in-memory representation > for the grant heads (i.e. need more than 32 bits for byte count), so > we should probably handle that up front in the sysfs API... > Ok. reserve_grant_head and write_grant_head in the decimal format of "cycle:bytes" it is. I'll leave the names of the others and convert them to a similar "cycle:blocks" format. Thanks! Brian > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs