On Tue, Jul 15, 2008 at 12:16:32PM -0600, Matthew Wilcox wrote: > On Tue, Jul 15, 2008 at 11:57:40AM -0600, Alex Chiang wrote: > > My thought was that big SMP systems like ia64, possibly sparc and > > ppc, and increasingly, x86, might find something like this > > useful, as systems get larger and larger, and vendors are going > > to want to do RAS-ish features, like the ability to keep CPUs in > > firmware across reboots until told otherwise by the sysadmin. > > > > Right now, a 'present' CPU strongly implies 'online' as well, > > since we're calling cpu_up() for all 'present' CPUs in > > smp_init(). But this hurts if: > > > > - you don't actually want to bring up all 'present' CPUs > > - you still want to interact with these weirdo zombie > > CPUs that are 'present' but not 'online' > > Have you considered simply failing __cpu_up() for CPUs that are > deconfigured by firmware? But what if you want to have a system boot with, say, 4 CPUs and then decide at run time to bring up another 4 CPUs when required? How about having smp_init() call into arch code to query whether it should bring up a not-already-online CPU? Architectures that want to do something special can then make the decision there and everyone else can define the test completely away. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
