Commit-ID: 9131fc302013a6ccf052f3d14553386f9b3ee2ff
Gitweb: http://git.kernel.org/tip/9131fc302013a6ccf052f3d14553386f9b3ee2ff
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Thu, 11 Jun 2009 11:25:05 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 11 Jun 2009 13:16:18 +0200
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@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/linux/perf_counter.h | 2 +-
kernel/perf_counter.c | 27 +++++++++++++++++++--------
kernel/sysctl.c | 6 +++---
3 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 386be91..95c797c 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -650,7 +650,7 @@ extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
extern int sysctl_perf_counter_paranoid;
extern int sysctl_perf_counter_mlock;
-extern int sysctl_perf_counter_limit;
+extern int sysctl_perf_counter_sample_rate;
extern void perf_counter_init(void);
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_mmap_counters __read_mostly;
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 @@ static inline bool perf_paranoid_kernel(void)
}
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 @@ static void perf_ctx_adjust_freq(struct perf_counter_context *ctx)
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 @@ static int perf_counter_period(struct perf_counter *counter, u64 __user *arg)
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 @@ int perf_counter_overflow(struct perf_counter *counter, int nmi,
} 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 @@ SYSCALL_DEFINE5(perf_counter_open,
return -EACCES;
}
+ if (attr.freq) {
+ if (attr.sample_freq > sysctl_perf_counter_sample_rate)
+ return -EINVAL;
+ }
+
/*
* Get the target context (task or percpu):
*/
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 4b072ad..a7e4eb0 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -940,9 +940,9 @@ static struct ctl_table kern_table[] = {
},
{
.ctl_name = CTL_UNNUMBERED,
- .procname = "perf_counter_int_limit",
- .data = &sysctl_perf_counter_limit,
- .maxlen = sizeof(sysctl_perf_counter_limit),
+ .procname = "perf_counter_max_sample_rate",
+ .data = &sysctl_perf_counter_sample_rate,
+ .maxlen = sizeof(sysctl_perf_counter_sample_rate),
.mode = 0644,
.proc_handler = &proc_dointvec,
},
--
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