perf_counter: Rename perf_counter_limit sysctl
Rename perf_counter_limit to perf_counter_max_sample_rate and
prohibit creation of counters with a known higher sample
frequency.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 63f1987..3b2829d 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -44,11 +44,12 @@
static atomic_t nr_comm_counters __read_mostly;
/*
- * 0 - not paranoid
- * 1 - disallow cpu counters to unpriv
- * 2 - disallow kernel profiling to unpriv
+ * perf counter paranoia level:
+ * 0 - not paranoid
+ * 1 - disallow cpu counters to unpriv
+ * 2 - disallow kernel profiling to unpriv
*/
-int sysctl_perf_counter_paranoid __read_mostly; /* do we need to be privileged */
+int sysctl_perf_counter_paranoid __read_mostly;
static inline bool perf_paranoid_cpu(void)
{
@@ -61,7 +62,11 @@
}
int sysctl_perf_counter_mlock __read_mostly = 512; /* 'free' kb per user */
-int sysctl_perf_counter_limit __read_mostly = 100000; /* max NMIs per second */
+
+/*
+ * max perf counter sample rate
+ */
+int sysctl_perf_counter_sample_rate __read_mostly = 100000;
static atomic64_t perf_counter_id;
@@ -1244,7 +1249,7 @@
if (interrupts == MAX_INTERRUPTS) {
perf_log_throttle(counter, 1);
counter->pmu->unthrottle(counter);
- interrupts = 2*sysctl_perf_counter_limit/HZ;
+ interrupts = 2*sysctl_perf_counter_sample_rate/HZ;
}
if (!counter->attr.freq || !counter->attr.sample_freq)
@@ -1682,7 +1687,7 @@
spin_lock_irq(&ctx->lock);
if (counter->attr.freq) {
- if (value > sysctl_perf_counter_limit) {
+ if (value > sysctl_perf_counter_sample_rate) {
ret = -EINVAL;
goto unlock;
}
@@ -2979,7 +2984,8 @@
} else {
if (hwc->interrupts != MAX_INTERRUPTS) {
hwc->interrupts++;
- if (HZ * hwc->interrupts > (u64)sysctl_perf_counter_limit) {
+ if (HZ * hwc->interrupts >
+ (u64)sysctl_perf_counter_sample_rate) {
hwc->interrupts = MAX_INTERRUPTS;
perf_log_throttle(counter, 0);
ret = 1;
@@ -3639,6 +3645,11 @@
return -EACCES;
}
+ if (attr.freq) {
+ if (attr.sample_freq > sysctl_perf_counter_sample_rate)
+ return -EINVAL;
+ }
+
/*
* Get the target context (task or percpu):
*/