Messages in this thread | | | Date | Mon, 2 May 2005 22:46:19 +0530 | From | Dinakar Guniguntala <> | Subject | Re: [RFC PATCH] Dynamic sched domains (v0.5) |
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On Mon, May 02, 2005 at 07:44:05PM +1000, Nick Piggin wrote: > Dinakar Guniguntala wrote: > > >+void rebuild_sched_domains(cpumask_t span1, cpumask_t span2) > >+{ > >+ cpumask_t change_map; > >+ > >+ cpus_or(change_map, span1, span2); > >+ > >+ preempt_disable(); > > Oh, you can't do this here, attach_domains does a synchronize_kernel. > So take it out, it doesn't do anything anyway, does it?
I put that in to prevent hangs with CONFIG_PREEMPT turned on, but clearly didn't test it with preempt turned on. Looks like all I need to do here is a local_irq_disable
> > I suggest you also use some sort of locking to prevent concurrent rebuilds > and rebuilds racing with cpu hotplug. You could probably have a static > semaphore around rebuild_sched_domains, and take lock_cpu_hotplug here too.
I already do a lock_cpu_hotplug() in cpuset.c before calling rebuild_sched_domains and also am holding cpuset_sem, so that should take care of both hotplug and concurrent rebuilds
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