Messages in this thread | | | Subject | Re: [PATCH] io stalls | From | Chris Mason <> | Date | 11 Jun 2003 22:22:28 -0400 |
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On Wed, 2003-06-11 at 21:29, Andrea Arcangeli wrote:
> this will avoid get_request_wait_wakeup to mess the wakeup, so we can > wakep_nr(rq.count) safely. > > then there's the last issue raised by Chris, that is if we get request > released faster than the tasks can run, still we can generate a not > perfect fairness. My solution to that is to change wake_up to have a > nr_exclusive not obeying to the try_to_wakeup retval. that should > guarantee exact FIFO then, but it's a minor issue because the requests > shouldn't be released systematically in a flood. So I'm leaving it > opened for now, the others already addressed should be the major ones.
I think the only time we really need to wakeup more than one waiter is when we hit the q->batch_request mark. After that, each new request that is freed can be matched with a single waiter, and we know that any previously finished requests have probably already been matched to their own waiter.
-chris
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