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authorZwane Mwaikambo <zwane@linuxpower.ca>2005-06-25 17:54:50 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-25 19:24:29 -0400
commitf370513640492641b4046bfd9a6e4714f6ae530d (patch)
tree46da47197fcbb3614b51c5f1fac841bf26d5e572 /arch/s390/kernel/smp.c
parentd92de65cab5980c16d4a1c326c1ef9a591892883 (diff)
[PATCH] i386 CPU hotplug
(The i386 CPU hotplug patch provides infrastructure for some work which Pavel is doing as well as for ACPI S3 (suspend-to-RAM) work which Li Shaohua <shaohua.li@intel.com> is doing) The following provides i386 architecture support for safely unregistering and registering processors during runtime, updated for the current -mm tree. In order to avoid dumping cpu hotplug code into kernel/irq/* i dropped the cpu_online check in do_IRQ() by modifying fixup_irqs(). The difference being that on cpu offline, fixup_irqs() is called before we clear the cpu from cpu_online_map and a long delay in order to ensure that we never have any queued external interrupts on the APICs. There are additional changes to s390 and ppc64 to account for this change. 1) Add CONFIG_HOTPLUG_CPU 2) disable local APIC timer on dead cpus. 3) Disable preempt around irq balancing to prevent CPUs going down. 4) Print irq stats for all possible cpus. 5) Debugging check for interrupts on offline cpus. 6) Hacky fixup_irqs() to redirect irqs when cpus go off/online. 7) play_dead() for offline cpus to spin inside. 8) Handle offline cpus set in flush_tlb_others(). 9) Grab lock earlier in smp_call_function() to prevent CPUs going down. 10) Implement __cpu_disable() and __cpu_die(). 11) Enable local interrupts in cpu_enable() after fixup_irqs() 12) Don't fiddle with NMI on dead cpu, but leave intact on other cpus. 13) Program IRQ affinity whilst cpu is still in cpu_online_map on offline. Signed-off-by: Zwane Mwaikambo <zwane@linuxpower.ca> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/s390/kernel/smp.c')
-rw-r--r--arch/s390/kernel/smp.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index fdfcf0488b49..93c71fef99dc 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -679,12 +679,14 @@ __cpu_disable(void)
679{ 679{
680 unsigned long flags; 680 unsigned long flags;
681 ec_creg_mask_parms cr_parms; 681 ec_creg_mask_parms cr_parms;
682 int cpu = smp_processor_id();
682 683
683 spin_lock_irqsave(&smp_reserve_lock, flags); 684 spin_lock_irqsave(&smp_reserve_lock, flags);
684 if (smp_cpu_reserved[smp_processor_id()] != 0) { 685 if (smp_cpu_reserved[cpu] != 0) {
685 spin_unlock_irqrestore(&smp_reserve_lock, flags); 686 spin_unlock_irqrestore(&smp_reserve_lock, flags);
686 return -EBUSY; 687 return -EBUSY;
687 } 688 }
689 cpu_clear(cpu, cpu_online_map);
688 690
689#ifdef CONFIG_PFAULT 691#ifdef CONFIG_PFAULT
690 /* Disable pfault pseudo page faults on this cpu. */ 692 /* Disable pfault pseudo page faults on this cpu. */