Re: [Xen-devel] [PATCH RFC 09/12] xen-blkback: move pendinghandles list from blkbk to pending_req

[Jan Beulich]

>>> On 28.02.13 at 11:28, Roger Pau Monne <roger.pau@xxxxxxxxxx> wrote:
> Moving grant ref handles from blkbk to pending_req will allow us to
> get rid of the shared blkbk structure.

At the expense of (slightly?) higher memory requirements?

> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -136,6 +136,7 @@ struct pending_req {
>  	struct list_head	free_list;
>  	struct persistent_gnt	*persistent_gnts[BLKIF_MAX_SEGMENTS_PER_REQUEST];
>  	struct page		*pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
> +	grant_handle_t		grant_handles[BLKIF_MAX_SEGMENTS_PER_REQUEST];

Adding yet another array here makes it even more desirable to
switch from multiple arrays to a singly array of a structure, thus
improving locality of the memory accesses involved in processing
an individual segment.

Jan

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/