From: Mike Snitzer <snitzer@redhat.com>
To: Joe Thornber <thornber@redhat.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
device-mapper development <dm-devel@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] dmcache: flush superblock stats when retrieving status info
Date: Fri, 10 May 2013 08:53:57 -0400 [thread overview]
Message-ID: <20130510125357.GA7687@redhat.com> (raw)
In-Reply-To: <20130510101005.GE20880@debian>
On Fri, May 10 2013 at 6:10am -0400,
Joe Thornber <thornber@redhat.com> wrote:
> On Thu, May 09, 2013 at 01:44:38PM -0700, Darrick J. Wong wrote:
> > When userspace queries dmcache for stats info, we should ensure that all the
> > metadata gets flushed out of memory to disk. The current code neglects to
> > update the disk copy of the hit/miss counters.
>
> Nack, I'm afraid. The commit is there purely to make sure the free
> metadata blocks reported from the status are as high as possible.
> [When a transaction is open we have to treat all blocks from the
> previous transaction as allocated to allow rollback.]
Right the commit is about presenting a more accurate status. Darrick's
patch doesn't change what is reported for hit/miss counts (they are
reported from in-core counters already, so accuracy isn't a concern).
So I agree with what you're saying. Thanks Joe.
next prev parent reply other threads:[~2013-05-10 12:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-08 21:48 dm-cache not writing out cache metadata at reboot? Darrick J. Wong
2013-05-08 22:05 ` Mike Snitzer
2013-05-08 23:23 ` Darrick J. Wong
2013-05-09 20:36 ` Darrick J. Wong
2013-05-09 20:44 ` [PATCH 1/2] dmcache: flush superblock stats when retrieving status info Darrick J. Wong
2013-05-10 10:10 ` Joe Thornber
2013-05-10 12:53 ` Mike Snitzer [this message]
2013-05-09 20:47 ` dm-cache not writing out cache metadata at reboot? Mike Snitzer
2013-05-09 20:47 ` [PATCH 2/2] dmcache: Implement a flush message Darrick J. Wong
2013-05-10 10:22 ` [dm-devel] " Joe Thornber
2013-05-10 17:51 ` Darrick J. Wong
2013-05-11 15:25 ` Mike Snitzer
2013-05-13 12:04 ` Peter Rajnoha
2013-05-13 21:36 ` [dm-devel] " Darrick J. Wong
2013-05-10 10:05 ` [dm-devel] dm-cache not writing out cache metadata at reboot? Joe Thornber
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