Messages in this thread |  | | | Date | Tue, 7 Feb 2006 08:42:20 -0800 (PST) | | From | Linus Torvalds <> | | Subject | Re: [PATCH] percpu data: only iterate over possible CPUs |
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On Tue, 7 Feb 2006, Eric Dumazet wrote: > > This patch assumes that cpu_possible_map is setup before > setup_per_cpu_areas(). > > That sounds a reasonable assumption, but maybe not on your architecture ?
I have to say, it sounds not just like a reasonable assumption, but like the only sane assumption that there _could_ be.
> I dont think cpu_possible_map has to be filled at smp_prepare_cpus() time, but > long before. > > On i386/x86_64/ia64, this is done from setup_arch() called from start_kernel() > just before setup_per_cpu_areas() > > On powerpc it's done from setup_system(), called before start_kernel()
It absolutely _has_ to be done from setup_arch() or earlier, as shown by the fact that "setup_per_cpu_areas()" is the very next thing that init/main.c calls (and clearly, that needs to know what CPU's are possible).
ppc64 certainly calls it early enough, as does x86/x86-64/ia64. I don't see anybody else doing it too late either.
Heiko, can you point to the "old comment" you mentioned in the email, or the architecture that does this wrong?
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