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Date: Wed, 02 May 2012 08:39:02 -0500
From: Mark Tinguely <tinguely@sgi.com>
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Subject: Re: [PATCH 06/10] xfs: struct xfs_buf_log_format isn't variable sized.
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To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com

On 04/24/12 01:33, Dave Chinner wrote:
> From: Dave Chinner<dchinner@redhat.com>
>
> The struct xfs_buf_log_format wants to think the dirty bitmap is
> variable sized.  In fact, it is variable size on disk simply due to
> the way we map it from the in-memory structure, but we still just
> use a fixed size memory allocation for the in-memory structure.
>
> Hence it makes no sense to set the function up as a variable sized
> structure when we already know it's maximum size, and we always
> allocate it as such. Simplify the structure by making the dirty
> bitmap a fixed sized array and just using the size of the structure
> for the allocation size.
>
> This will make it much simpler to allocate and manipulate an array
> of format structures for discontiguous buffer support.
>
> The previous struct xfs_buf_log_item size according to
> /proc/slabinfo was 224 bytes. pahole doesn't give the same size
> because of the variable size definition. With this modification,
> pahole reports the same as /proc/slabinfo:
>
> 	/* size: 224, cachelines: 4, members: 6 */
>
> Signed-off-by: Dave Chinner<dchinner@redhat.com>

Looks good.

Reviewed-by: Mark Tinguely <tinguely@sgi.com>

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