ftrace: make use of tracing_cpumask (36dfe925) · Commits · e / devices / android_kernel_xiaomi_markw

kernel/trace/trace.c

+64 −31

Original line number	Diff line number	Diff line
		@@ -70,23 +70,6 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);

		unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;

		/*
		* Only trace on a CPU if the bitmask is set:
		*/
		static cpumask_t tracing_cpumask __read_mostly = CPU_MASK_ALL;

		/*
		* The tracer itself will not take this lock, but still we want
		* to provide a consistent cpumask to user-space:
		*/
		static DEFINE_MUTEX(tracing_cpumask_update_lock);

		/*
		* Temporary storage for the character representation of the
		* CPU bitmask:
		*/
		static char mask_str[NR_CPUS];

		void trace_wake_up(void)
		{
		/*
		@@ -1776,19 +1759,46 @@ static struct file_operations show_traces_fops = {
		.release = seq_release,
		};

		/*
		* Only trace on a CPU if the bitmask is set:
		*/
		static cpumask_t tracing_cpumask = CPU_MASK_ALL;

		/*
		* When tracing/tracing_cpu_mask is modified then this holds
		* the new bitmask we are about to install:
		*/
		static cpumask_t tracing_cpumask_new;

		/*
		* The tracer itself will not take this lock, but still we want
		* to provide a consistent cpumask to user-space:
		*/
		static DEFINE_MUTEX(tracing_cpumask_update_lock);

		/*
		* Temporary storage for the character representation of the
		* CPU bitmask (and one more byte for the newline):
		*/
		static char mask_str[NR_CPUS + 1];

		static ssize_t
		tracing_cpumask_read(struct file filp, char __user ubuf,
		size_t count, loff_t *ppos)
		{
		int err;

		count = min(count, (size_t)NR_CPUS);
		int len;

		mutex_lock(&tracing_cpumask_update_lock);
		cpumask_scnprintf(mask_str, NR_CPUS, tracing_cpumask);
		err = copy_to_user(ubuf, mask_str, count);
		if (err)
		count = -EFAULT;

		len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
		if (count - len < 2) {
		count = -EINVAL;
		goto out_err;
		}
		len += sprintf(mask_str + len, "\n");
		count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);

		out_err:
		mutex_unlock(&tracing_cpumask_update_lock);

		return count;
		@@ -1798,16 +1808,40 @@ static ssize_t
		tracing_cpumask_write(struct file filp, const char __user ubuf,
		size_t count, loff_t *ppos)
		{
		int err;
		int err, cpu;

		mutex_lock(&tracing_cpumask_update_lock);
		err = cpumask_parse_user(ubuf, count, tracing_cpumask);
		mutex_unlock(&tracing_cpumask_update_lock);

		err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
		if (err)
		return err;
		goto err_unlock;

		spin_lock_irq(&ftrace_max_lock);
		for_each_possible_cpu(cpu) {
		/*
		* Increase/decrease the disabled counter if we are
		* about to flip a bit in the cpumask:
		*/
		if (cpu_isset(cpu, tracing_cpumask) &&
		!cpu_isset(cpu, tracing_cpumask_new)) {
		atomic_inc(&global_trace.data[cpu]->disabled);
		}
		if (!cpu_isset(cpu, tracing_cpumask) &&
		cpu_isset(cpu, tracing_cpumask_new)) {
		atomic_dec(&global_trace.data[cpu]->disabled);
		}
		}
		spin_unlock_irq(&ftrace_max_lock);

		tracing_cpumask = tracing_cpumask_new;

		mutex_unlock(&tracing_cpumask_update_lock);

		return count;

		err_unlock:
		mutex_unlock(&tracing_cpumask_update_lock);

		return err;
		}

		static struct file_operations tracing_cpumask_fops = {
		@@ -1846,8 +1880,7 @@ tracing_iter_ctrl_read(struct file filp, char __user ubuf,
		r += sprintf(buf + r, "\n");
		WARN_ON(r >= len + 2);

		r = simple_read_from_buffer(ubuf, cnt, ppos,
		buf, r);
		r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);

		kfree(buf);