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Subject: Re: [PATCH 12/16] xfs: implement batched inode lookups for AG walking
From: Alex Elder <aelder@sgi.com>
In-Reply-To: <20100924091522.GT2614@dastard>
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Date: Mon, 27 Sep 2010 11:05:04 -0500
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To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com

On Fri, 2010-09-24 at 19:15 +1000, Dave Chinner wrote:
> On Thu, Sep 23, 2010 at 12:17:05PM -0500, Alex Elder wrote:
> > On Wed, 2010-09-22 at 16:44 +1000, Dave Chinner wrote:
> > > From: Dave Chinner <dchinner@redhat.com>
> > > 
> > > With the reclaim code separated from the generic walking code, it is
> > > simple to implement batched lookups for the generic walk code.

. . .

> > The gang lookup should never return
> > anything beyond the end of the AG.  It seems
> > like you ought to be able to detect when you've
> > covered all the whole AG elsewhere,
> 
> AFAICT, there are only two ways - the gang lookup returns nothing,
> or we see the last valid inode number in the AG. If you can come up
> with something that doesn't invlove a tree or inode number lookup,
> I'm all ears....

I didn't have anything specific in mind and was basing
this somewhat on gut feeling so you probably have the
best solution as-is.  But I'll look at your new code
and if I come up with any bright ideas I'll let you
know.

					-Alex

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