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powerpc: Update cpu_sibling_maps dynamically

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Rather doing one initialization pass over all the per-cpu
cpu_sibling_maps at boot, update the maps at cpu online/offline time.

This is a behavior change -- the thread_siblings attribute now
reflects only online siblings, whereas it would display offline
siblings before.  The new behavior matches that of x86, and is
arguably more useful.

Signed-off-by: Nathan Lynch <ntl@pobox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Nathan Lynch
2008-07-27 15:24:52 +10:00
committed by Benjamin Herrenschmidt
parent 9ba1984ead
commit e2075f79a9
3 changed files with 29 additions and 30 deletions
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32
arch/powerpc/kernel/smp.c
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@@ -41,6 +41,7 @@
#include <asm/smp.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include <asm/cputhreads.h>
#include <asm/cputable.h>
#include <asm/system.h>
#include <asm/mpic.h>
@@ -228,6 +229,7 @@ void __devinit smp_prepare_boot_cpu(void)
BUG_ON(smp_processor_id() != boot_cpuid);
cpu_set(boot_cpuid, cpu_online_map);
cpu_set(boot_cpuid, per_cpu(cpu_sibling_map, boot_cpuid));
#ifdef CONFIG_PPC64
paca[boot_cpuid].__current = current;
#endif
@@ -380,6 +382,7 @@ int __cpuinit __cpu_up(unsigned int cpu)
int __devinit start_secondary(void *unused)
{
unsigned int cpu = smp_processor_id();
int i, base;
atomic_inc(&init_mm.mm_count);
current->active_mm = &init_mm;
@@ -400,6 +403,14 @@ int __devinit start_secondary(void *unused)
ipi_call_lock();
cpu_set(cpu, cpu_online_map);
/* Update sibling maps */
base = cpu_first_thread_in_core(cpu);
for (i = 0; i < threads_per_core; i++) {
if (cpu_is_offline(base + i))
continue;
cpu_set(cpu, per_cpu(cpu_sibling_map, base + i));
cpu_set(base + i, per_cpu(cpu_sibling_map, cpu));
}
ipi_call_unlock();
local_irq_enable();
@@ -437,10 +448,25 @@ void __init smp_cpus_done(unsigned int max_cpus)
#ifdef CONFIG_HOTPLUG_CPU
int __cpu_disable(void)
{
if (smp_ops->cpu_disable)
return smp_ops->cpu_disable();
int cpu = smp_processor_id();
int base, i;
int err;
return -ENOSYS;
if (!smp_ops->cpu_disable)
return -ENOSYS;
err = smp_ops->cpu_disable();
if (err)
return err;
/* Update sibling maps */
base = cpu_first_thread_in_core(cpu);
for (i = 0; i < threads_per_core; i++) {
cpu_clear(cpu, per_cpu(cpu_sibling_map, base + i));
cpu_clear(base + i, per_cpu(cpu_sibling_map, cpu));
}
return 0;
}
void __cpu_die(unsigned int cpu)