From: Mikulas Patocka <mpatocka@redhat.com>
To: Mike Snitzer <snitzer@redhat.com>
Cc: device-mapper development <dm-devel@redhat.com>, lvm-devel@redhat.com
Subject: Re: rebased snapshot-merge patches
Date: Sat, 12 Sep 2009 03:54:36 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0909120350300.22286@hs20-bc2-1.build.redhat.com> (raw)
In-Reply-To: <20090912065608.GA1864@redhat.com>
On Sat, 12 Sep 2009, Mike Snitzer wrote:
> On Fri, Sep 11 2009 at 2:51am -0400,
> Mike Snitzer <snitzer@redhat.com> wrote:
>
> > Mikulas,
> >
> > I ran with your suggestion and it works quite well (results below).
> ...
> > The changes are detailed at the end of this mail. I still have a "TODO"
> > that you'll see in the patch that speaks to needing to have
> > snapshot_merge_process() check all origin chunks via __chunk_is_tracked()
> > rather than just the one check of the first chunk. Your feedback here
> > would be much appreciated. I'm not completely clear on the intent of
> > the __chunk_is_tracked() check there and what it now needs to do.
>
> I believe I've sorted this out. The TODO should've read something like:
> snapshot_merge_process() should delay the merging of _all_ chunks
> that have in-progress writes; not just the first chunk in the region
> that is to be merged.
>
> The revised patch (relative to Jon's unified snapshot tree) is here:
> http://people.redhat.com/msnitzer/patches/snapshot-merge/kernel_unified/2.6.31/dm-snapshot-merge-use-larger-io-when-merging.patch
>
> Pretty sure it _should_ work; but can't test until we get this unified
> snapshot patchset working properly.
Yes, that's right. The purpose of the tracking while merging is to exclude
pending writes to the region that is being merged --- so we must wait for
writes on all chunks. The patch seems fine.
Mikulas
WARNING: multiple messages have this Message-ID (diff)
From: Mikulas Patocka <mpatocka@redhat.com>
To: lvm-devel@redhat.com
Subject: Re: rebased snapshot-merge patches
Date: Sat, 12 Sep 2009 03:54:36 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0909120350300.22286@hs20-bc2-1.build.redhat.com> (raw)
In-Reply-To: <20090912065608.GA1864@redhat.com>
On Sat, 12 Sep 2009, Mike Snitzer wrote:
> On Fri, Sep 11 2009 at 2:51am -0400,
> Mike Snitzer <snitzer@redhat.com> wrote:
>
> > Mikulas,
> >
> > I ran with your suggestion and it works quite well (results below).
> ...
> > The changes are detailed at the end of this mail. I still have a "TODO"
> > that you'll see in the patch that speaks to needing to have
> > snapshot_merge_process() check all origin chunks via __chunk_is_tracked()
> > rather than just the one check of the first chunk. Your feedback here
> > would be much appreciated. I'm not completely clear on the intent of
> > the __chunk_is_tracked() check there and what it now needs to do.
>
> I believe I've sorted this out. The TODO should've read something like:
> snapshot_merge_process() should delay the merging of _all_ chunks
> that have in-progress writes; not just the first chunk in the region
> that is to be merged.
>
> The revised patch (relative to Jon's unified snapshot tree) is here:
> http://people.redhat.com/msnitzer/patches/snapshot-merge/kernel_unified/2.6.31/dm-snapshot-merge-use-larger-io-when-merging.patch
>
> Pretty sure it _should_ work; but can't test until we get this unified
> snapshot patchset working properly.
Yes, that's right. The purpose of the tracking while merging is to exclude
pending writes to the region that is being merged --- so we must wait for
writes on all chunks. The patch seems fine.
Mikulas
next prev parent reply other threads:[~2009-09-12 7:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-31 22:08 rebased snapshot-merge patches Mike Snitzer
2009-08-31 22:08 ` Mike Snitzer
2009-09-08 14:17 ` [dm-devel] " Mikulas Patocka
2009-09-08 14:17 ` Mikulas Patocka
2009-09-11 6:51 ` Mike Snitzer
2009-09-11 6:51 ` Mike Snitzer
2009-09-12 6:56 ` Mike Snitzer
2009-09-12 6:56 ` Mike Snitzer
2009-09-12 7:54 ` Mikulas Patocka [this message]
2009-09-12 7:54 ` Mikulas Patocka
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