From: Thomas Gleixner Date: Fri, 12 Oct 2007 21:04:07 +0000 (+0200) Subject: x86: Fix irq0 / local apic timer accounting X-Git-Tag: v2.6.24-rc1~1397^2~16 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e77ae3e105d28aa9410585715d83818f0abe871;p=linux-2.6 x86: Fix irq0 / local apic timer accounting The clock events merge introduced a change to the nmi watchdog code to handle the not longer increasing local apic timer count in the broadcast mode. This is fine for UP, but on SMP it pampers over a stuck CPU which is not handling the broadcast interrupt due to the unconditional sum up of local apic timer count and irq0 count. To cover all cases we need to keep track on which CPU irq0 is handled. In theory this is CPU#0 due to the explicit disabling of irq balancing for irq0, but there are systems which ignore this on the hardware level. The per cpu irq0 accounting allows us to remove the irq0 to CPU0 binding as well. Add a per cpu counter for irq0 and evaluate this instead of the global irq0 count in the nmi watchdog code. Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven --- diff --git a/arch/x86/kernel/nmi_64.c b/arch/x86/kernel/nmi_64.c index 0ec6d2ddb9..e60ac0da52 100644 --- a/arch/x86/kernel/nmi_64.c +++ b/arch/x86/kernel/nmi_64.c @@ -329,7 +329,7 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) touched = 1; } - sum = read_pda(apic_timer_irqs); + sum = read_pda(apic_timer_irqs) + read_pda(irq0_irqs); if (__get_cpu_var(nmi_touch)) { __get_cpu_var(nmi_touch) = 0; touched = 1; diff --git a/arch/x86/kernel/time_64.c b/arch/x86/kernel/time_64.c index 7781df1d50..16f58886e8 100644 --- a/arch/x86/kernel/time_64.c +++ b/arch/x86/kernel/time_64.c @@ -194,6 +194,8 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id) static irqreturn_t timer_event_interrupt(int irq, void *dev_id) { + add_pda(irq0_irqs, 1); + global_clock_event->event_handler(global_clock_event); return IRQ_HANDLED; diff --git a/include/asm-x86/pda.h b/include/asm-x86/pda.h index 5642634843..fb49f80eb9 100644 --- a/include/asm-x86/pda.h +++ b/include/asm-x86/pda.h @@ -29,6 +29,7 @@ struct x8664_pda { short isidle; struct mm_struct *active_mm; unsigned apic_timer_irqs; + unsigned irq0_irqs; } ____cacheline_aligned_in_smp; extern struct x8664_pda *_cpu_pda[];