From f370513640492641b4046bfd9a6e4714f6ae530d Mon Sep 17 00:00:00 2001 From: Zwane Mwaikambo Date: Sat, 25 Jun 2005 14:54:50 -0700 Subject: [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 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ppc64/kernel/pSeries_smp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'arch/ppc64/kernel') diff --git a/arch/ppc64/kernel/pSeries_smp.c b/arch/ppc64/kernel/pSeries_smp.c index 30154140f7e..62c55a12356 100644 --- a/arch/ppc64/kernel/pSeries_smp.c +++ b/arch/ppc64/kernel/pSeries_smp.c @@ -93,10 +93,13 @@ static int query_cpu_stopped(unsigned int pcpu) int pSeries_cpu_disable(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 */ -- cgit v1.2.3