summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2010-09-08 11:13:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-09-08 11:13:16 -0700
commit899edae615c806f78880077bd46f04d7f23ae6e6 (patch)
treeae3918d9947a8c4811e86217fc77b3927784492d /arch/x86/kernel
parentc8c727db413e18414dc6ebc2cc4f18f390763e17 (diff)
parent4177c42a6301a34c20038ec2771a33dcc30bb338 (diff)
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf, x86: Try to handle unknown nmis with an enabled PMU perf, x86: Fix handle_irq return values perf, x86: Fix accidentally ack'ing a second event on intel perf counter oprofile, x86: fix init_sysfs() function stub lockup_detector: Sync touch_*_watchdog back to old semantics tracing: Fix a race in function profile oprofile, x86: fix init_sysfs error handling perf_events: Fix time tracking for events with pid != -1 and cpu != -1 perf: Initialize callchains roots's childen hits oprofile: fix crash when accessing freed task structs
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/cpu/perf_event.c59
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel.c15
-rw-r--r--arch/x86/kernel/cpu/perf_event_p4.c2
3 files changed, 56 insertions, 20 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index f2da20fda02..3efdf2870a3 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1154,7 +1154,7 @@ static int x86_pmu_handle_irq(struct pt_regs *regs)
/*
* event overflow
*/
- handled = 1;
+ handled++;
data.period = event->hw.last_period;
if (!x86_perf_event_set_period(event))
@@ -1200,12 +1200,20 @@ void perf_events_lapic_init(void)
apic_write(APIC_LVTPC, APIC_DM_NMI);
}
+struct pmu_nmi_state {
+ unsigned int marked;
+ int handled;
+};
+
+static DEFINE_PER_CPU(struct pmu_nmi_state, pmu_nmi);
+
static int __kprobes
perf_event_nmi_handler(struct notifier_block *self,
unsigned long cmd, void *__args)
{
struct die_args *args = __args;
- struct pt_regs *regs;
+ unsigned int this_nmi;
+ int handled;
if (!atomic_read(&active_events))
return NOTIFY_DONE;
@@ -1214,22 +1222,47 @@ perf_event_nmi_handler(struct notifier_block *self,
case DIE_NMI:
case DIE_NMI_IPI:
break;
-
+ case DIE_NMIUNKNOWN:
+ this_nmi = percpu_read(irq_stat.__nmi_count);
+ if (this_nmi != __get_cpu_var(pmu_nmi).marked)
+ /* let the kernel handle the unknown nmi */
+ return NOTIFY_DONE;
+ /*
+ * This one is a PMU back-to-back nmi. Two events
+ * trigger 'simultaneously' raising two back-to-back
+ * NMIs. If the first NMI handles both, the latter
+ * will be empty and daze the CPU. So, we drop it to
+ * avoid false-positive 'unknown nmi' messages.
+ */
+ return NOTIFY_STOP;
default:
return NOTIFY_DONE;
}
- regs = args->regs;
-
apic_write(APIC_LVTPC, APIC_DM_NMI);
- /*
- * Can't rely on the handled return value to say it was our NMI, two
- * events could trigger 'simultaneously' raising two back-to-back NMIs.
- *
- * If the first NMI handles both, the latter will be empty and daze
- * the CPU.
- */
- x86_pmu.handle_irq(regs);
+
+ handled = x86_pmu.handle_irq(args->regs);
+ if (!handled)
+ return NOTIFY_DONE;
+
+ this_nmi = percpu_read(irq_stat.__nmi_count);
+ if ((handled > 1) ||
+ /* the next nmi could be a back-to-back nmi */
+ ((__get_cpu_var(pmu_nmi).marked == this_nmi) &&
+ (__get_cpu_var(pmu_nmi).handled > 1))) {
+ /*
+ * We could have two subsequent back-to-back nmis: The
+ * first handles more than one counter, the 2nd
+ * handles only one counter and the 3rd handles no
+ * counter.
+ *
+ * This is the 2nd nmi because the previous was
+ * handling more than one counter. We will mark the
+ * next (3rd) and then drop it if unhandled.
+ */
+ __get_cpu_var(pmu_nmi).marked = this_nmi + 1;
+ __get_cpu_var(pmu_nmi).handled = handled;
+ }
return NOTIFY_STOP;
}
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index d8d86d01400..ee05c90012d 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -712,7 +712,8 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
struct perf_sample_data data;
struct cpu_hw_events *cpuc;
int bit, loops;
- u64 ack, status;
+ u64 status;
+ int handled = 0;
perf_sample_data_init(&data, 0);
@@ -728,6 +729,7 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
loops = 0;
again:
+ intel_pmu_ack_status(status);
if (++loops > 100) {
WARN_ONCE(1, "perfevents: irq loop stuck!\n");
perf_event_print_debug();
@@ -736,19 +738,22 @@ again:
}
inc_irq_stat(apic_perf_irqs);
- ack = status;
intel_pmu_lbr_read();
/*
* PEBS overflow sets bit 62 in the global status register
*/
- if (__test_and_clear_bit(62, (unsigned long *)&status))
+ if (__test_and_clear_bit(62, (unsigned long *)&status)) {
+ handled++;
x86_pmu.drain_pebs(regs);
+ }
for_each_set_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) {
struct perf_event *event = cpuc->events[bit];
+ handled++;
+
if (!test_bit(bit, cpuc->active_mask))
continue;
@@ -761,8 +766,6 @@ again:
x86_pmu_stop(event);
}
- intel_pmu_ack_status(ack);
-
/*
* Repeat if there is more work to be done:
*/
@@ -772,7 +775,7 @@ again:
done:
intel_pmu_enable_all(0);
- return 1;
+ return handled;
}
static struct event_constraint *
diff --git a/arch/x86/kernel/cpu/perf_event_p4.c b/arch/x86/kernel/cpu/perf_event_p4.c
index 7e578e9cc58..b560db3305b 100644
--- a/arch/x86/kernel/cpu/perf_event_p4.c
+++ b/arch/x86/kernel/cpu/perf_event_p4.c
@@ -692,7 +692,7 @@ static int p4_pmu_handle_irq(struct pt_regs *regs)
inc_irq_stat(apic_perf_irqs);
}
- return handled > 0;
+ return handled;
}
/*