Re: [Xen-devel] [PATCH] xenbus_client: extend interface to suppurt multi-page ring

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2013-08-23 at 23:27 +0100, Wei Liu wrote:
> Originally Xen PV drivers only use single-page ring to pass along
> information. This might limit the throughput between frontend and
> backend.
> 
> The patch extends Xenbus driver to support multi-page ring, which in
> general should improve throughput if ring is the bottleneck. Changes to
> various frontend / backend to adapt to the new interface are also
> included.

The changes to the front/backends here simply adapt to the new interface
but don't actually make use of it, right?

> @@ -196,15 +200,18 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev, 
> struct xenbus_watch *watch,
>                        const char *pathfmt, ...);
>  
>  int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state 
> new_state);
> -int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
> -int xenbus_map_ring_valloc(struct xenbus_device *dev,
> -                        int gnt_ref, void **vaddr);
> -int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
> -                        grant_handle_t *handle, void *vaddr);
> +int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
> +                   unsigned int nr_pages, grant_ref_t *grefs);
> +int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs,
> +                        unsigned int nr_grefs, void **vaddr);

In the definition nr_grefs is called grefs_order. From the usage I think
the definition and not this prototype is correct.

Ian.


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