Re: [PATCH] sched: Fix adverse effects of NFS client on interactiveresponse
From: Peter Williams
Date: Fri Dec 23 2005 - 08:44:09 EST
Trond Myklebust wrote:
On Fri, 2005-12-23 at 21:49 +1100, Peter Williams wrote:
No. It is asking whether the NORMAL interruption of this interruptible
sleep will be caused by a human user action such as a keystroke or mouse
action. For the NFS client the answer to that question is unequivically
no. It's not a matter of policy it's a matter of fact.
/*
* Tasks that have marked their sleep as noninteractive get
* woken up without updating their sleep average. (i.e. their
* sleep is handled in a priority-neutral manner, no priority
* boost and no penalty.)
*/
This appears to be the only documentation for the TASK_NONINTERACTIVE
flag,
I guess it makes to many assumptions about the reader's prior knowledge
of the scheduler internals. I'll try to make it clearer.
and I see no mention of human user actions in that comment. The
comment rather appears to states that this particular flag is designed
to switch between two different scheduling policies.
Changes of scheduling policy only occur via calls to sched_setscheduler().
If the flag really is only about identifying sleeps that will involve
human user actions, then surely it would be easy to set up a short set
of guidelines in Documentation, say, that spell out exactly what the
purpose is, and when it should be used.
Sounds reasonable. I'll propose some changes to the scheduler
documentation.
That should be done _before_ one starts charging round converting every
instance of TASK_INTERRUPTIBLE.
Peter
--
Peter Williams pwil3058@xxxxxxxxxxxxxx
"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
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