Messages in this thread | | | Date | Wed, 25 Mar 2009 23:13:37 -0400 | From | Theodore Tso <> | Subject | Re: Linux 2.6.29 |
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On Thu, Mar 26, 2009 at 01:50:10PM +1100, Neil Brown wrote: > I shouldn't be too hard to add some concept of total time to this. > If we track the number of write-outs per unit time and use that together > with a "target time for fsync" to scale the 'dirty_bytes' number, we > might be able to auto-tune the amount of dirty space to fit the speeds > of the drives. > > We would probably start with each device having a very low "max dirty" > number which would cause writeouts to start soon. Once the device > demonstrates that it can do n-per-second (or whatever) the VM would > allow the "max dirty" number to drift upwards. I'm not sure how best > to get it to move downwards if the device slows down (or the kernel > over-estimated). Maybe it should regularly decay so that the device > keeps have to "prove" itself.
This seems like a really cool idea.
-Ted
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