diff options
Diffstat (limited to 'arch/i386/kernel/nmi.c')
| -rw-r--r-- | arch/i386/kernel/nmi.c | 50 |
1 files changed, 39 insertions, 11 deletions
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c index eaafe233a5d..a5e34d65596 100644 --- a/arch/i386/kernel/nmi.c +++ b/arch/i386/kernel/nmi.c @@ -22,6 +22,7 @@ #include <linux/percpu.h> #include <linux/dmi.h> #include <linux/kprobes.h> +#include <linux/cpumask.h> #include <asm/smp.h> #include <asm/nmi.h> @@ -42,6 +43,8 @@ int nmi_watchdog_enabled; static DEFINE_PER_CPU(unsigned long, perfctr_nmi_owner); static DEFINE_PER_CPU(unsigned long, evntsel_nmi_owner[3]); +static cpumask_t backtrace_mask = CPU_MASK_NONE; + /* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's * offset from MSR_P4_BSU_ESCR0. It will be the max for all platforms (for now) */ @@ -192,6 +195,8 @@ static __cpuinit inline int nmi_known_cpu(void) return 0; } +static int endflag __initdata = 0; + #ifdef CONFIG_SMP /* The performance counters used by NMI_LOCAL_APIC don't trigger when * the CPU is idle. To make sure the NMI watchdog really ticks on all @@ -199,7 +204,6 @@ static __cpuinit inline int nmi_known_cpu(void) */ static __init void nmi_cpu_busy(void *data) { - volatile int *endflag = data; local_irq_enable_in_hardirq(); /* Intentionally don't use cpu_relax here. This is to make sure that the performance counter really ticks, @@ -207,14 +211,13 @@ static __init void nmi_cpu_busy(void *data) pause instruction. On a real HT machine this is fine because all other CPUs are busy with "useless" delay loops and don't care if they get somewhat less cycles. */ - while (*endflag == 0) - barrier(); + while (endflag == 0) + mb(); } #endif static int __init check_nmi_watchdog(void) { - volatile int endflag = 0; unsigned int *prev_nmi_count; int cpu; @@ -867,14 +870,16 @@ static unsigned int void touch_nmi_watchdog (void) { - int i; + if (nmi_watchdog > 0) { + unsigned cpu; - /* - * Just reset the alert counters, (other CPUs might be - * spinning on locks we hold): - */ - for_each_possible_cpu(i) - alert_counter[i] = 0; + /* + * Just reset the alert counters, (other CPUs might be + * spinning on locks we hold): + */ + for_each_present_cpu (cpu) + alert_counter[cpu] = 0; + } /* * Tickle the softlockup detector too: @@ -907,6 +912,16 @@ __kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) touched = 1; } + if (cpu_isset(cpu, backtrace_mask)) { + static DEFINE_SPINLOCK(lock); /* Serialise the printks */ + + spin_lock(&lock); + printk("NMI backtrace for cpu %d\n", cpu); + dump_stack(); + spin_unlock(&lock); + cpu_clear(cpu, backtrace_mask); + } + sum = per_cpu(irq_stat, cpu).apic_timer_irqs; /* if the apic timer isn't firing, this cpu isn't doing much */ @@ -1033,6 +1048,19 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file, #endif +void __trigger_all_cpu_backtrace(void) +{ + int i; + + backtrace_mask = cpu_online_map; + /* Wait for up to 10 seconds for all CPUs to do the backtrace */ + for (i = 0; i < 10 * 1000; i++) { + if (cpus_empty(backtrace_mask)) + break; + mdelay(1); + } +} + EXPORT_SYMBOL(nmi_active); EXPORT_SYMBOL(nmi_watchdog); EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi); |