location of bioq lock

[Luigi Rizzo]

On Tue, Jul 12, 2005 at 10:03:14PM +0200, Poul-Henning Kamp wrote:
> 
> I must admit that I have often been tempted to move the queue+sorting
> out of the drivers because they all, more or less, do the exact
> same thing.
> 
> For one thing, that would simplify any ABI for changing disksort
> algorithm (which should be per drive and not per system).

yes this is true - in fact we are looking at the feasibility of
a per-drive disksort too.
What is really complex with the current infrastructure is
implementing non work-conserving algorithms, e.g. the anticipatory
scheduling (see  http://www.cs.rice.edu/~ssiyer/r/antsched/ )
because there you need to hook into the equivalent of if_start()
for network interfaces, and at the moment each driver does
it in a different way...


> The last bit of this is that disksorting seldom does much for us
> these days, apart from mitigating the the lemming syncer.

true again... (not that i dobted that phk knows a lot here :)
in fact i see it more as something to improve fairness, rather
than something to improve throughput.

	cheers
	luigi