On Thu, Sep 12, 2013 at 05:35:43PM +0100, Chris Wilson wrote: > Not quite, as it would be possible for the evil userspace to trigger a > GPU hang that would cause the sane userspace to spin indefinitely > waiting for the error recovery to kick in.
So with FIFOn+1 preempting FIFOn its a live-lock because the faulting thread will forever keep yielding to itself since its the highest priority task around, therefore the set_need_resched() is an absolute NOP in that case. For OTHER it might run another task with set_need_resched(), without set_need_resched() it'll simply spin on the fault until it runs out of time and gets force preempted and another task gets to run. So for either case, the set_need_resched() doesn't make an appreciable difference. Removing it will not make evil userspace much worse -- at worst it will cause slightly more wasted cycles. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
