perf_counter: Add ioctl for changing the sample period/frequency (08247e31) · Commits · 戴 / test

include/linux/perf_counter.h

+5 −4

Original line number	Diff line number	Diff line
		@@ -164,10 +164,11 @@ struct perf_counter_hw_event {
		/*
		* Ioctls that can be done on a perf counter fd:
		*/
		#define PERF_COUNTER_IOC_ENABLE _IOW('$', 0, u32)
		#define PERF_COUNTER_IOC_DISABLE _IOW('$', 1, u32)
		#define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32)
		#define PERF_COUNTER_IOC_RESET _IOW('$', 3, u32)
		#define PERF_COUNTER_IOC_ENABLE _IO ('$', 0)
		#define PERF_COUNTER_IOC_DISABLE _IO ('$', 1)
		#define PERF_COUNTER_IOC_REFRESH _IO ('$', 2)
		#define PERF_COUNTER_IOC_RESET _IO ('$', 3)
		#define PERF_COUNTER_IOC_PERIOD _IOW('$', 4, u64)

		enum perf_counter_ioc_flags {
		PERF_IOC_FLAG_GROUP = 1U << 0,

+41 −0

Original line number	Diff line number	Diff line
		@@ -1604,6 +1604,43 @@ static void perf_counter_for_each(struct perf_counter *counter,
		mutex_unlock(&counter->child_mutex);
		}

		static int perf_counter_period(struct perf_counter counter, u64 __user arg)
		{
		struct perf_counter_context *ctx = counter->ctx;
		unsigned long size;
		int ret = 0;
		u64 value;

		if (!counter->hw_event.sample_period)
		return -EINVAL;

		size = copy_from_user(&value, arg, sizeof(value));
		if (size != sizeof(value))
		return -EFAULT;

		if (!value)
		return -EINVAL;

		spin_lock_irq(&ctx->lock);
		if (counter->hw_event.freq) {
		if (value > sysctl_perf_counter_limit) {
		ret = -EINVAL;
		goto unlock;
		}

		counter->hw_event.sample_freq = value;
		} else {
		counter->hw_event.sample_period = value;
		counter->hw.sample_period = value;

		perf_log_period(counter, value);
		}
		unlock:
		spin_unlock_irq(&ctx->lock);

		return ret;
		}

		static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
		{
		struct perf_counter *counter = file->private_data;
		@@ -1623,6 +1660,10 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

		case PERF_COUNTER_IOC_REFRESH:
		return perf_counter_refresh(counter, arg);

		case PERF_COUNTER_IOC_PERIOD:
		return perf_counter_period(counter, (u64 __user *)arg);

		default:
		return -ENOTTY;
		}