Re: [PATCH v2 15/45] rcu: Use get/put_online_cpus_atomic() toprevent CPU offline

From: Steven Rostedt
Date: Wed Jun 26 2013 - 10:51:29 EST


On Wed, 2013-06-26 at 07:34 -0700, Paul E. McKenney wrote:
> On Wed, Jun 26, 2013 at 03:29:40PM +0100, David Laight wrote:
> > > Once stop_machine() is gone from the CPU offline path, we won't be able
> > > to depend on disabling preemption to prevent CPUs from going offline
> > > from under us.
> >
> > Could you use an rcu-like sequence so that disabling pre-emption
> > would be enough?
> >
> > Something like rebuilding the cpu list, then forcing yourself
> > to run on all the cpu.
> >
> > That would be far less intrusive.
>
> It would also increase the latency of CPU-hotunplug operations.
>

Is that a big deal?

-- Steve


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/