Messages in this thread | | | Date | Thu, 10 Oct 2013 12:16:16 -0700 | Subject | Re: [PATCH 0/6] Optimize the cpu hotplug locking -v2 | From | Linus Torvalds <> |
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On Thu, Oct 10, 2013 at 12:04 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > > I'm wondering if we can have a for_each_cpu() that only disables > preemption in the loop.
I think we'd generally want to have it be something the loop asks for.
If the loop is just some kind of "gather statistics" thing, I don't think it's required. The cost per loop is so low (usually adding up a couple of words) that the downside drowns the upside.
And we could easily look at MAXSMP (or NR_CPUS) at compile-time, and not do it for common small values (although it looks like Fedora defaults to 128 CPU's for their distro kernels, which seems a bit excessive - too many by far for normal people, too few for the crazy big ones).
Linus
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