From: Dave Chinner <david@fromorbit.com>
To: Jeff Liu <jeff.liu@oracle.com>
Cc: "xfs@oss.sgi.com" <xfs@oss.sgi.com>
Subject: Re: [PATCH] xfs: improve xfs_iext_destroy() by freeing extent indirection array directly
Date: Tue, 24 Sep 2013 09:50:17 +1000 [thread overview]
Message-ID: <20130923235017.GX9901@dastard> (raw)
In-Reply-To: <523FCA18.1000204@oracle.com>
On Mon, Sep 23, 2013 at 12:56:56PM +0800, Jeff Liu wrote:
> On 09/23/2013 08:36 AM, Dave Chinner wrote:
>
> > On Fri, Sep 20, 2013 at 10:41:22PM +0800, Jeff Liu wrote:
> >> From: Jie Liu <jeff.liu@oracle.com>
> >>
> >> To free the incore file extents stores at the indirection array, we
> >> call the common routine xfs_iext_irec_remove() to remove a record
> >> from the array one at a time in reverse order, which will resize an
> >> extent indirection array repeatedly according to the array size.
> >>
> >> This is not often the case to make a file with thousands extent records
> >> stores at an indirection array, but above operation is inefficient and
> >> could result in memory fragments.
> >
> > Yes, it may be inefficient, but I don't see that it's a contributor
> > to memory fragmentation as the reallocated buffer is freed shortly
> > after it has been allocated as the array shrinks. Do you have any
> > evidence to suggest that such behaviour is actually fragmenting
> > memory? If so, is the any test case that reproduces this problem?
>
> Ah, yes, it should not cause memory fragmentation.
>
> The benefits is that this change could save alloc/free buffers depending
> on the number of extents records are stored at indirection array.
OK, can you send a new version with an updated commit message?
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2013-09-23 23:50 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-20 14:41 [PATCH] xfs: improve xfs_iext_destroy() by freeing extent indirection array directly Jeff Liu
2013-09-23 0:36 ` Dave Chinner
2013-09-23 4:56 ` Jeff Liu
2013-09-23 23:50 ` Dave Chinner [this message]
2013-09-24 14:05 ` Jeff Liu
-- strict thread matches above, loose matches on Subject: below --
2013-09-20 13:21 Jeff Liu
2013-09-20 14:39 ` Jeff Liu
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