Re: virtio ring cleanups, which save stack on older gcc

Rusty Russell
2014-05-29T11:09:11Z

Minchan Kim <minchan@kernel.org> writes:
> Hello Rusty,
>
> On Thu, May 29, 2014 at 04:56:41PM +0930, Rusty Russell wrote:
>> They don't make much difference: the easier fix is use gcc 4.8
>> which drops stack required across virtio block's virtio_queue_rq
>> down to that kmalloc in virtio_ring from 528 to 392 bytes.
>>
>> Still, these (*lightly tested*) patches reduce to 432 bytes,
>> even for gcc 4.6.4. Posted here FYI.
>
> I am testing with below which was hack for Dave's idea so don't have
> a machine to test your patches until tomorrow.
> So, I will queue your patches into testing machine tomorrow morning.

More interesting would be updating your compiler to 4.8, I think.
Saving <100 bytes on virtio is not going to save you, right?

Cheers,
Rusty.