Messages in this thread | | | Date | Thu, 4 Nov 2004 17:57:55 -0800 | From | Ashok Raj <> | Subject | Re: [RFC/PATCH 3/4] introduce cpu_add and cpu_remove |
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On Sun, Oct 24, 2004 at 05:42:31AM -0400, Nathan Lynch wrote: > > These functions safely update cpu_present_map (i.e. with the > cpucontrol semaphore held) and register or unregister the cpu device > as needed. These are needed by systems which can add or remove cpus > from the system after boot (e.g. ppc64 and ia64), and are intended to > be called from the platform-specific code such as the ACPI or Open > Firmware layers. > > Signed-off-by: Nathan Lynch <nathanl@austin.ibm.com> > > > --- > > > + > +/* > + * Add a cpu to the system. Return the number of the cpu added, > + * or NR_CPUS if no more slots available. > + */ > +unsigned int cpu_add(void) > +{ > + unsigned int cpu = NR_CPUS; > + > + lock_cpu_hotplug(); > + > + if (num_present_cpus() == num_possible_cpus()) > +goto out; > + > + for_each_cpu(cpu) > + if (!cpu_present(cpu)) > + break;
could we simplify this by
cpus_compliment(cpu_compliment_map, cpu_present_map); cpu = first_cpu(cpu_compliment_map);
> + > + if (register_cpu(cpu)) { > + cpu = NR_CPUS; > + goto out; > + } > + cpu_set(cpu, cpu_present_map);
I would prefer that register_cpu is performed in arch side, as there may be other setup necessary to capture the hardware->logical associations before consuming these.
> +out: > + unlock_cpu_hotplug(); > + return cpu; > +} > + > +/* > + * Remove a cpu from the system. > + */ > +void cpu_remove(unsigned int cpu) > +{ > + lock_cpu_hotplug(); > + > + BUG_ON(cpu_present(cpu)); > + > + unregister_cpu(cpu); > + > + cpu_clear(cpu, cpu_present_map); > + > + unlock_cpu_hotplug(); > +} > #else > static inline int cpu_run_sbin_hotplug(unsigned int cpu, const char *action) > { > > _ > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
-- Cheers, Ashok Raj - Linux OS & Technology Team - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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