Messages in this thread | | | Date | Wed, 29 May 2002 17:15:52 +0200 | From | Andrea Arcangeli <> | Subject | Re: [PATCH] updated O(1) scheduler for 2.4 |
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On Tue, May 28, 2002 at 07:57:00PM -0700, Robert Love wrote: > On Fri, 2002-05-24 at 09:02, J.A. Magallon wrote: > > > I had to make this to get it built: > > <snip> > > Thanks, I have put these changes into the 2.4.19-pre9 version of the > patch which is available at: > > http://www.kernel.org/pub/linux/kernel/people/rml/sched/ingo-O1/sched-O1-rml-2.4.19-pre9-1.patch
I merged it and I've almost finished moving everything on top of it but I've a few issues.
can you elaborate why you __save_flags in do_fork? do_fork is even a blocking operation. fork_by_hand runs as well with irq enabled. I don't like to safe flags in a fast path if it's not required.
Then there are longstanding bugs that aren't yet fixed and I ported the fixed on top of it (see the parent-timeslice patch in -aa).
the child-run first approch in o1 is suspect, it seems the parent will keep running just after a wasteful reschedule, a sched yield instead should be invoked like in -aa in the share-timeslice patch in order to roll the current->run_list before the schedule is invoked while returning to userspace after fork.
another suspect thing I noticed is the wmb() in resched_task. Can you elaborate on what is it trying to serialize (I hope not the read of p->need_resched with the stuff below)? Also if something it should be a smp_wmb(), same smp_ prefix goes for the other mb() in schedule.
thanks,
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