From: Zwane Mwaikambo <zwane@linuxpower.ca>
This patch moves the cpu_online_map cpu clearing to __cpu_disable so that
any necessary arch changes can be made before doing the clear. This
simplifies a APIC timer interrupt race fix which went in.
Signed-off-by: Zwane Mwaikambo <zwane@linuxpower.ca>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/kernel/smpboot.c | 21 +++++++++------------
25-akpm/arch/ia64/kernel/smpboot.c | 3 ++-
25-akpm/arch/ppc64/kernel/smp.c | 4 +++-
25-akpm/arch/s390/kernel/smp.c | 4 +++-
25-akpm/kernel/cpu.c | 21 +++++----------------
5 files changed, 22 insertions(+), 31 deletions(-)
diff -puN arch/i386/kernel/smpboot.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable arch/i386/kernel/smpboot.c
--- 25/arch/i386/kernel/smpboot.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable 2004-09-11 17:25:54.786427280 -0700
+++ 25-akpm/arch/i386/kernel/smpboot.c 2004-09-11 17:25:54.795425912 -0700
@@ -1132,18 +1132,6 @@ static int __devinit cpu_enable(unsigned
return 0;
}
-void __cpu_prep_disable(void)
-{
- /* We enable the timer again on the exit path of the death loop */
- if (smp_processor_id() != 0) {
- disable_APIC_timer();
- /* Allow any queued timer interrupts to get serviced */
- local_irq_enable();
- mdelay(1);
- local_irq_disable();
- }
-}
-
int __cpu_disable(void)
{
/*
@@ -1157,6 +1145,15 @@ int __cpu_disable(void)
if (smp_processor_id() == 0)
return -EBUSY;
+ /* We enable the timer again on the exit path of the death loop */
+ disable_APIC_timer();
+ /* Allow any queued timer interrupts to get serviced */
+ local_irq_enable();
+ mdelay(1);
+ local_irq_disable();
+
+ /* It's now safe to remove this processor from the online map */
+ cpu_clear(smp_processor_id(), cpu_online_map);
fixup_irqs();
return 0;
}
diff -puN arch/ia64/kernel/smpboot.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable arch/ia64/kernel/smpboot.c
--- 25/arch/ia64/kernel/smpboot.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable 2004-09-11 17:25:54.787427128 -0700
+++ 25-akpm/arch/ia64/kernel/smpboot.c 2004-09-11 17:25:54.796425760 -0700
@@ -591,9 +591,10 @@ int __cpu_disable(void)
if (cpu == 0)
return -EBUSY;
+ cpu_clear(cpu, cpu_online_map);
fixup_irqs();
local_flush_tlb_all();
- printk ("Disabled cpu %u\n", smp_processor_id());
+ printk("Disabled cpu %u\n", cpu);
return 0;
}
diff -puN arch/ppc64/kernel/smp.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable arch/ppc64/kernel/smp.c
--- 25/arch/ppc64/kernel/smp.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable 2004-09-11 17:25:54.789426824 -0700
+++ 25-akpm/arch/ppc64/kernel/smp.c 2004-09-11 17:25:54.797425608 -0700
@@ -255,11 +255,13 @@ int __cpu_disable(void)
{
/* FIXME: go put this in a header somewhere */
extern void xics_migrate_irqs_away(void);
+ int cpu = smp_processor_id();
+ cpu_clear(cpu, cpu_online_map);
systemcfg->processorCount--;
/*fix boot_cpuid here*/
- if (smp_processor_id() == boot_cpuid)
+ if (cpu == boot_cpuid)
boot_cpuid = any_online_cpu(cpu_online_map);
/* FIXME: abstract this to not be platform specific later on */
diff -puN arch/s390/kernel/smp.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable arch/s390/kernel/smp.c
--- 25/arch/s390/kernel/smp.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable 2004-09-11 17:25:54.790426672 -0700
+++ 25-akpm/arch/s390/kernel/smp.c 2004-09-11 17:25:54.798425456 -0700
@@ -688,13 +688,15 @@ __cpu_disable(void)
{
unsigned long flags;
ec_creg_mask_parms cr_parms;
+ int cpu = smp_processor_id();
spin_lock_irqsave(&smp_reserve_lock, flags);
- if (smp_cpu_reserved[smp_processor_id()] != 0) {
+ if (smp_cpu_reserved[cpu] != 0) {
spin_unlock_irqrestore(&smp_reserve_lock, flags);
return -EBUSY;
}
+ cpu_clear(cpu, cpu_online_map);
/* disable all external interrupts */
cr_parms.start_ctl = 0;
diff -puN kernel/cpu.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable kernel/cpu.c
--- 25/kernel/cpu.c~hotplug-cpu-move-cpu_online_map-clear-to-__cpu_disable 2004-09-11 17:25:54.792426368 -0700
+++ 25-akpm/kernel/cpu.c 2004-09-11 17:25:54.798425456 -0700
@@ -84,31 +84,20 @@ static int cpu_run_sbin_hotplug(unsigned
return call_usermodehelper(argv[0], argv, envp, 0);
}
-void __attribute__((weak)) __cpu_prep_disable(void)
-{
-}
-
/* Take this CPU down. */
static int take_cpu_down(void *unused)
{
int err;
- /* Prepatory work before clearing the cpu off the online map */
- __cpu_prep_disable();
-
- /* Take offline: makes arch_cpu_down somewhat easier. */
- cpu_clear(smp_processor_id(), cpu_online_map);
-
/* Ensure this CPU doesn't handle any more interrupts. */
err = __cpu_disable();
if (err < 0)
- cpu_set(smp_processor_id(), cpu_online_map);
- else
- /* Force idle task to run as soon as we yield: it should
- immediately notice cpu is offline and die quickly. */
- sched_idle_next();
+ return err;
- return err;
+ /* Force idle task to run as soon as we yield: it should
+ immediately notice cpu is offline and die quickly. */
+ sched_idle_next();
+ return 0;
}
int cpu_down(unsigned int cpu)
_