Re: kswapd's priority

Raul Miller (rdm@test.legislate.com)
Sat, 27 Jun 1998 11:25:58 -0400


Stephen C. Tweedie <sct@dcs.ed.ac.uk> wrote:
> Now, it's fairly clear how we can do priority inheritance if there is
> only one process responsible for waking up any specific wait-queue.
> Things get far more complex if that property does not hold. How, for
> example, do we manage priorities in the case of nfs clients where we
> have 5 nfs rpc threads by default, all of which may be busy servicing
> somebody else's low-priority request at the time the realtime process
> makes an nfs IO? We'd have to be able to assign groups of processes to
> groups of wait-queues in order to propogate the priority of any realtime
> process which blocks on one of those wait-queues.

You can optimize a bit by giving the wait queue a priority (and a
count of how many mebers of the queue are at this priority). When
a higher priority process arrives, you change the priority (and
set the count to 1). When all processes at some given priority
leave, you walk the queue.

-- 
Raul

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