lkml.org 
[lkml]   [2012]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v2 1/3] virtio_net: Split receive buffer alloc/add
On Tue, Jan 10, 2012 at 5:30 PM, Rusty Russell <rusty@rustcorp.com.au> wrote:
> On Tue, 10 Jan 2012 09:41:01 -0800, Mike Waychison <mikew@google.com> wrote:
>> In preparation for allocating receive buffers in the slow path without
>> disabling NAPI, split the allocation and addition of receive buffers
>> apart into two separate functions (per receive buffer type).
>>
>> While here, move the vi->num accounting into the add functions.
>>
>> Signed-off-by: Mike Waychison <mikew@google.com>
>
> Hi Mike...
>
>        This exposes a nasty ugliness in the way virtio_net works.  We
> allocate an skbuff for the small packet case, and just allocate the
> pages for the large packet cases, and alloc the skbuff when we fill the
> pages.
>
>        I think all the allocators should return a populated skbuff;
> this uses a bit more memory in theory, but should make the code simpler.
> As an added bonus, your life should get much simpler for these patches.
>
> I'll try to create such a patch tonight, but I'm busy finalizing my
> linux.conf.au presentation, so it might take longer :(
>

This seems reasonable for the "big" receive buffers, but I don't think
it makes a lot of sense for "mergeable" receive buffers as best I can
tell. Hopefully making this work isn't too hard though :)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2012-01-11 02:45    [W:0.056 / U:0.784 seconds]
©2003-2014 Jasper Spaans. Advertise on this site