Commit-ID: dea47c786c4a4198f4d6e6ba860ce59729c45481
Gitweb: http://git.kernel.org/tip/dea47c786c4a4198f4d6e6ba860ce59729c45481
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 4 May 2009 18:47:44 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 4 May 2009 19:04:46 +0200
perf_counter: x86: fixup nmi_watchdog vs perf_counter boo-boo
Invert the atomic_inc_not_zero() test so that we will indeed detect the
first activation.
Also rename the global num_counters, since its easy to confuse with
x86_pmu.num_counters.
[ Impact: fix non-working perfcounters on AMD CPUs, cleanup ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
LKML-Reference: <1241455664.7620.4938.camel@twins>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/kernel/cpu/perf_counter.c | 14 +++++++-------
1 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c
index d4c0cc9..196b58f 100644
--- a/arch/x86/kernel/cpu/perf_counter.c
+++ b/arch/x86/kernel/cpu/perf_counter.c
@@ -171,7 +171,7 @@ again:
return new_raw_count;
}
-static atomic_t num_counters;
+static atomic_t active_counters;
static DEFINE_MUTEX(pmc_reserve_mutex);
static bool reserve_pmc_hardware(void)
@@ -224,7 +224,7 @@ static void release_pmc_hardware(void)
static void hw_perf_counter_destroy(struct perf_counter *counter)
{
- if (atomic_dec_and_mutex_lock(&num_counters, &pmc_reserve_mutex)) {
+ if (atomic_dec_and_mutex_lock(&active_counters, &pmc_reserve_mutex)) {
release_pmc_hardware();
mutex_unlock(&pmc_reserve_mutex);
}
@@ -248,12 +248,12 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
return -ENODEV;
err = 0;
- if (atomic_inc_not_zero(&num_counters)) {
+ if (!atomic_inc_not_zero(&active_counters)) {
mutex_lock(&pmc_reserve_mutex);
- if (atomic_read(&num_counters) == 0 && !reserve_pmc_hardware())
+ if (atomic_read(&active_counters) == 0 && !reserve_pmc_hardware())
err = -EBUSY;
else
- atomic_inc(&num_counters);
+ atomic_inc(&active_counters);
mutex_unlock(&pmc_reserve_mutex);
}
if (err)
@@ -280,7 +280,7 @@ static int __hw_perf_counter_init(struct perf_counter *counter)
if (capable(CAP_SYS_ADMIN) && hw_event->nmi)
hwc->nmi = 1;
- hwc->irq_period = hw_event->irq_period;
+ hwc->irq_period = hw_event->irq_period;
if ((s64)hwc->irq_period <= 0 || hwc->irq_period > x86_pmu.max_period)
hwc->irq_period = x86_pmu.max_period;
@@ -871,7 +871,7 @@ perf_counter_nmi_handler(struct notifier_block *self,
struct pt_regs *regs;
int ret;
- if (!atomic_read(&num_counters))
+ if (!atomic_read(&active_counters))
return NOTIFY_DONE;
switch (cmd) {
--
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