Messages in this thread | | | Date | Mon, 28 Aug 2006 11:28:30 +1000 | From | David Chinner <> | Subject | Re: RFC - how to balance Dirty+Writeback in the face of slow writeback. |
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On Fri, Aug 25, 2006 at 08:37:24AM +0200, Jens Axboe wrote: > On Fri, Aug 25 2006, Neil Brown wrote: > > > I'm beginning to think that the current scheme really works very well > > - except for a few 'bugs'(*). > > It works ok, but it makes it hard to experiment with larger queue depths > when the vm falls apart :-). It's not a big deal, though, even if the > design isn't very nice - nr_requests is not a well defined entity. It > can be anywhere from 512b to megabyte(s) in size. So throttling on X > number of requests tends to be pretty vague and depends hugely on the > workload (random vs sequential IO).
So maybe we need a different control parameter - the amount of memory we allow to be backed up in a queue rather than the number of requests the queue can take...
Cheers,
Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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