Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [patch 5/8] Immediate Values - x86 Optimization (simplified) | Date | Tue, 20 Nov 2007 10:06:34 +1100 |
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On Tuesday 20 November 2007 01:28:03 Mathieu Desnoyers wrote: > * Rusty Russell (rusty@rustcorp.com.au) wrote: > > I think it would be easier to just fast-path the num_online_cpus == 1 > > case, even if you want to keep this "update_early" interface. > > Nope, that could lead to problems. I call core_immediate_update() > _very_ early, before boot_cpu_init() is called.
Ah, I see the problem. It would in fact be clearer for us to move boot_cpu_init() up to just after smp_setup_processor_id() in start_kernel anyway, not just for this code, but in general.
> Therefore, > cpu_online_map is not set yet. I am not sure the benefit of using > num_online_cpus outweights the added fragility wrt other boot process > initializations.
I think it's still a win, though worth a comment that we always go via the non-IPI path for the early boot case.
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