* Russell King <rmk+lkml@xxxxxxxxxxxxxxxx>: > On Tue, Jul 15, 2008 at 01:15:15PM -0600, Alex Chiang wrote: > > * Russell King <rmk+lkml@xxxxxxxxxxxxxxxx>: > > > > > > 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. > > > > So this is exactly what I'm doing. The ia64 patch has this hunk: > > > > @@ -820,6 +824,9 @@ __cpu_up (unsigned int cpu) > > if (cpu_isset(cpu, cpu_callin_map)) > > return -EINVAL; > > > > + if (!cpu_isset(cpu, cpu_enabled_map)) > > + return -EINVAL; > > + > > per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; > > /* Processor goes to start_secondary(), sets online flag */ > > ret = do_boot_cpu(sapicid, cpu); > > > > That was the easiest, most-straightforward solution I could think > > of. If you have an idea for a version with lower taxes (doesn't > > touch all the archs or can be #define'd out), I'm happy to hear > > it. > > I think I did make a suggestion in the bit you quote from me above. > > Let me be more explicit: Thanks, sorry for being dense. > static void __init smp_init(void) > { > unsigned int cpu; > > /* FIXME: This should be done in userspace --RR */ > for_each_present_cpu(cpu) { > if (num_online_cpus() >= setup_max_cpus) > break; > - if (!cpu_online(cpu)) > + if (smp_cpu_enabled(cpu) && !cpu_online(cpu)) > cpu_up(cpu); > } > > /* Any cleanup work */ > printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus()); > smp_cpus_done(setup_max_cpus); > } > > and have architectures provide 'smp_cpu_enabled(cpu)' which can either > be a function, inline function or a macro (and therefore possible to be > completely eliminated.) Yup, this is nicer. I'll try this. /ac -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html