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Commit df58ab24 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarPeter 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: default avatarIngo Molnar <mingo@elte.hu>
parent 0764771d

include/linux/perf_counter.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

kernel/perf_counter.c

+19 −8
Original line number Diff line number Diff line
@@ -44,11 +44,12 @@ static atomic_t nr_mmap_counters __read_mostly; 
static atomic_t nr_comm_counters __read_mostly;



/*

 * 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):

	 */

kernel/sysctl.c

+3 −3
Original line number Diff line number Diff line
@@ -932,9 +932,9 @@ 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,

	},