On Tue, Aug 30, 2011 at 5:57 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
> On 2011-08-30 18:50, Dan Ehrenberg wrote:
>> @@ -66,7 +107,16 @@ static int fio_libaio_getevents(struct thread_data *td, unsigned int min,
>> int r, events = 0;
>>
>> do {
>> - r = io_getevents(ld->aio_ctx, actual_min, max, ld->aio_events + events, t);
>> + if (td->o.userspace_libaio_reap == 1
>> + && actual_min == 0
>> + && ((struct aio_ring *)(ld->aio_ctx))->magic
>> + == AIO_RING_MAGIC) {
>> + r = user_io_getevents(ld->aio_ctx, max,
>> + ld->aio_events + events);
>> + } else {
>> + r = io_getevents(ld->aio_ctx, actual_min,
>> + max, ld->aio_events + events, t);
>> + }
>
> One question here - why depend on actual_min == 0? The check is
> practically free, would not hurt to do the user_io_getevents() first and
> punt to io_getevents() afterwards if need be.
I guess I don't need to depend on that, since you'll never be calling
both user_io_getevents() and sys_io_getevents() at the same time
still. It was just paranoia, really--if I'm not grabbing the ring_lock
spinlock that exists in the kernel, then I'll be really safe if I
never run code that wants to grab it. But I guess the condition is not
really necessary since the whole thing is single-threaded.
>
> --
> Jens Axboe
>
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