Messages in this thread | | | Subject | Re: [PATCH] backing dev unplugging | From | Christophe Saout <> | Date | Thu, 11 Mar 2004 14:11:19 +0100 |
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Am Do, den 11.03.2004 schrieb Jens Axboe um 13:22:
> > If we were out of memory the buffers were allocated from a mempool and I > > want to get it out as soon as possible. If we are OOM the write will > > most likely be the VM trying to free some memory and it would be > > counterproductive to wait. It is not unlikely that we are the only > > writer to that disk so there's a chance that the queue is not congested. > > Because it wasn't right, like most of those blk_run_queues(). The vm > should get things going, you basically just want to take a little nap > and retry. The idea with a small wait is to allow io to make some > progress, you gain nothing retrying right away (except wasting CPU > spinning). It might want to be 1 instead of HZ/100, though. I doubt it > would make much difference, since it's an OOM condition.
Well, okay. You're right then. I think the wait is unnecessary because the next thing that the code tries to do is to allocate a new page, waiting allowed and the VM will run the queue and wait itself. So if you think it's safe you can even remove it.
Thanks.
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