Re: [PATCH] xen-blkback: allocate list of pending reqs in small chunks

[David Vrabel <david.vrabel@citrix.com>]

On 26/04/13 14:45, Roger Pau Monne wrote:
> Allocate pending requests in smaller chunks instead of allocating them
> all at the same time.
> 
> This change also removes the global array of pending_reqs, it is no
> longer necessay.
> 
> Variables related to the grant mapping have been grouped into a struct
> called "grant_page", this allows to allocate them in smaller chunks,
> and also improves memory locality.
> 
[...]
> diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
> index afab208..2841c0f 100644
> --- a/drivers/block/xen-blkback/xenbus.c
> +++ b/drivers/block/xen-blkback/xenbus.c
> @@ -127,22 +128,53 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
>         blkif->free_pages_num = 0;
>         atomic_set(&blkif->persistent_gnt_in_use, 0);
> 
> -       blkif->pending_reqs = kcalloc(XEN_BLKIF_REQS,
> -                                     sizeof(blkif->pending_reqs[0]),
> -                                     GFP_KERNEL);
> -       if (!blkif->pending_reqs) {
> -               kmem_cache_free(xen_blkif_cachep, blkif);
> -               return ERR_PTR(-ENOMEM);
> -       }
>         INIT_LIST_HEAD(&blkif->pending_free);
> +
> +       pr_alert("sizeof req: %lu\n", sizeof(*req));

Stray pr_alert() here.

Looks good otherwise.

Reviewed-by: David Vrabel <david.vrabel@citrix.com>

David