Re: [Xen-devel] [PATCH 2/3] public/io/netif.h: document control ring and toeplitz hashing

[David Vrabel <david.vrabel@xxxxxxxxxx>]

On 04/01/16 11:14, Paul Durrant wrote:
>>>> You should use the standard ring format and infrastructure.
>>>
>>> Is there one for variable message size rings? I didn't find one. I
>>> don't want to use the fixed size balanced ring macros for control
>>> messages as fixed size messages really aren't appropriate in this case.
>>
>> Perhaps union the request/response message types with a uint8_t
>> pad[1024] and use this as the request/response type?
>>
> 
> The problem is that this places a 1k limit on the message size,
> which
> is not there in the scheme I'm proposing. I'd rather not bake that limit
> in if I don't have to.

>>>>> + * |                      req[1024]                |
                                 ^^^^^^^^^
Surely this limits your size to 1024 bytes?

Also if you need bigger messages you can grant those areas separately
and pass a grant ref through the ring, or you can chunk the message to
fit in several requests/responses.

David

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