Messages in this thread | | | Date | Wed, 19 Aug 2009 15:10:39 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] x86: Rendezvous all the cpu's for MTRR/PAT init |
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* Nick Piggin <npiggin@suse.de> wrote:
> On Tue, Aug 18, 2009 at 11:20:57PM -0700, Suresh B wrote: > > To make it clean I can move the smp_store_cpu_info() call before > > local_irq_disable() in smp_callin(). But that needs more changes (for > > xen etc). So thinking more, I think it is safe to do smp_call_function() > > with interrupts disabled as the caller is currently not in the > > cpu_online_mask. > > > > i.e., no one else sends smp_call_function interrupt to this AP who is > > doing smp_call_function() with interrupts disabled and as such there > > won't be any deadlocks typically associated with calling > > smp_call_function() with interrupts disabled. Copied Nick to confirm or > > correct my understanding. > > > > New patch appended removes this irq enable/disable sequence around > > mtrr_ap_init() and add's a cpu_online() check in smp_call_function > > warn-on's. > > Yes this seems like a fine idea to me. Maybe also add a > WARN_ON(cpu_online) in the interrupt-side as well just to > make it clear. > > If you split the patch out with its own changelog and give > a comment for the special case, then you can add an > Acked-by: Nick Piggin <npiggin@suse.de> > > Although until you get acks from all arch maintainers, the > functionality would have to only be used on a per-arch basis but > that's probably OK as it's a pretty tricky thing for generic code > to be doing :)
Also, Suresh, please generate patches with diffstat included so that the arch impact can be deducted at a glance.
Ingo
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