Messages in this thread | | | Date | Thu, 9 Feb 2006 11:23:43 -0600 | From | Nathan Lynch <> | Subject | Re: [PATCH] percpu data: only iterate over possible CPUs |
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Ashok Raj wrote: > On Thu, Feb 09, 2006 at 08:08:09AM -0800, Nathan Lynch wrote: > > > > powerpc/ppc64, for instance, determines the number of possible cpus > > from information exported by firmware (and I'm mystified as to why > > other platforms don't do this). So it's typical to have a kernel an a > > pSeries partition with NR_CPUS=128, but cpu_possible_map = 0xff. > > > > Iam assuming in the above ase, cpu_possible_map == cpu_present_map and both > dont change after the OS is booted. v.s in platforms capable of hot-plug > cpus present could grow up to cpu_possible_map (max) when a new cpu is > newly added, that wasnt even present at boot time.
No, cpu_present_map need not equal cpu_possible_map. Of course cpu_possible_map doesn't change after boot, but cpu_present_map can. Apart from that, I don't really understand what you're trying to say here.
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