[openib-general] [PATCH] use mmiowb after doorbell ring

[akepner at sgi.com]

On Tue, 17 Oct 2006, Michael S. Tsirkin wrote:

> Quoting r. Roland Dreier <rdreier at cisco.com>:
>> Subject: Re: [PATCH] use mmiowb after doorbell ring
>>
>>     Michael> BTW, something like this will be needed for userspace too?
>>
>> Ugh, I forgot about that.
>>
>> I don't think an mmiowb() equivalent is available from userspace.
>
> Isn't this just an asm() command?
>

Depends on the architecture, but on sn2, it's not.

(Actually, on most architectures, it's a no-op. See
arch/ia64/sn/kernel/iomv.c:__sn_mmiowb() for the sn2 
version.)

-- 
Arthur