Re: assign-dev: Purpose of interrupt_work

[Avi Kivity <avi@redhat.com>]

On 10/12/2009 09:50 AM, Jan Kiszka wrote:
>> Apic is lockless. For ioapic/pic I used spinlocks initially, but Avi
>> prefers mutexes. Theoretically it is possible to make them lockless,
>> but code will be complex and eventually more slow, since more then two
>> atomic operation will be used on irq injection path.
>>      
> Well, lockless is another thing.
>
> But also converting to spinlocks would indeed add some overhead:
> irqsave/restore. But I wonder if this isn't worth it, at least when
> looking at the (supposed to be fast) device passthrough scenario which
> would be simpler and faster.
>    

I'm worried about disabling irqs for non-device-assignment cases.  It 
would be more palatable if ioapic was completely O(1) (there are some 
per-vcpu loops in there, shouldn't be too bad for 16 vcpus, but we want 
to scale).

-- 
error compiling committee.c: too many arguments to function