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Commit ccfe9e42 authored by Alexander Z Lam's avatar Alexander Z Lam Committed by Steven Rostedt
Browse files

tracing: Make tracing_cpumask available for all instances 

Allow tracer instances to disable tracing by cpu by moving
the static global tracing_cpumask into trace_array.

Link: http://lkml.kernel.org/r/921622317f239bfc2283cac2242647801ef584f2.1375980149.git.azl@google.com



Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Signed-off-by: default avatarAlexander Z Lam <azl@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 836d481e

kernel/trace/trace.c

+20 −17
Original line number Diff line number Diff line
@@ -3165,11 +3165,6 @@ static const struct file_operations show_traces_fops = { 
	.llseek		= seq_lseek,

};



/*

 * Only trace on a CPU if the bitmask is set:

 */

static cpumask_var_t tracing_cpumask;



/*

 * The tracer itself will not take this lock, but still we want

 * to provide a consistent cpumask to user-space:
@@ -3186,11 +3181,12 @@ static ssize_t 
tracing_cpumask_read(struct file *filp, char __user *ubuf,

		     size_t count, loff_t *ppos)

{

	struct trace_array *tr = file_inode(filp)->i_private;

	int len;



	mutex_lock(&tracing_cpumask_update_lock);



	len = cpumask_scnprintf(mask_str, count, tracing_cpumask);

	len = cpumask_scnprintf(mask_str, count, tr->tracing_cpumask);

	if (count - len < 2) {

		count = -EINVAL;

		goto out_err;
@@ -3208,7 +3204,7 @@ static ssize_t 
tracing_cpumask_write(struct file *filp, const char __user *ubuf,

		      size_t count, loff_t *ppos)

{

	struct trace_array *tr = filp->private_data;

	struct trace_array *tr = file_inode(filp)->i_private;

	cpumask_var_t tracing_cpumask_new;

	int err, cpu;
@@ -3228,12 +3224,12 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf, 
		 * Increase/decrease the disabled counter if we are

		 * about to flip a bit in the cpumask:

		 */

		if (cpumask_test_cpu(cpu, tracing_cpumask) &&

		if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&

				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {

			atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);

			ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);

		}

		if (!cpumask_test_cpu(cpu, tracing_cpumask) &&

		if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&

				cpumask_test_cpu(cpu, tracing_cpumask_new)) {

			atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);

			ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
@@ -3242,7 +3238,7 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf, 
	arch_spin_unlock(&ftrace_max_lock);

	local_irq_enable();



	cpumask_copy(tracing_cpumask, tracing_cpumask_new);

	cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);



	mutex_unlock(&tracing_cpumask_update_lock);

	free_cpumask_var(tracing_cpumask_new);
@@ -3256,9 +3252,10 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf, 
}



static const struct file_operations tracing_cpumask_fops = {

	.open		= tracing_open_generic,

	.open		= tracing_open_generic_tr,

	.read		= tracing_cpumask_read,

	.write		= tracing_cpumask_write,

	.release	= tracing_release_generic_tr,

	.llseek		= generic_file_llseek,

};
@@ -5938,6 +5935,11 @@ static int new_instance_create(const char *name) 
	if (!tr->name)

		goto out_free_tr;



	if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))

		goto out_free_tr;



	cpumask_copy(tr->tracing_cpumask, cpu_all_mask);



	raw_spin_lock_init(&tr->start_lock);



	tr->current_trace = &nop_trace;
@@ -5969,6 +5971,7 @@ static int new_instance_create(const char *name) 
 out_free_tr:

	if (tr->trace_buffer.buffer)

		ring_buffer_free(tr->trace_buffer.buffer);

	free_cpumask_var(tr->tracing_cpumask);

	kfree(tr->name);

	kfree(tr);
@@ -6098,6 +6101,9 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer) 
{

	int cpu;



	trace_create_file("tracing_cpumask", 0644, d_tracer,

			  tr, &tracing_cpumask_fops);



	trace_create_file("trace_options", 0644, d_tracer,

			  tr, &tracing_iter_fops);
@@ -6147,9 +6153,6 @@ static __init int tracer_init_debugfs(void) 


	init_tracer_debugfs(&global_trace, d_tracer);



	trace_create_file("tracing_cpumask", 0644, d_tracer,

			&global_trace, &tracing_cpumask_fops);



	trace_create_file("available_tracers", 0444, d_tracer,

			&global_trace, &show_traces_fops);
@@ -6371,7 +6374,7 @@ __init static int tracer_alloc_buffers(void) 
	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))

		goto out;



	if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))

	if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))

		goto out_free_buffer_mask;



	/* Only allocate trace_printk buffers if a trace_printk exists */
@@ -6386,7 +6389,7 @@ __init static int tracer_alloc_buffers(void) 
		ring_buf_size = 1;



	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);

	cpumask_copy(tracing_cpumask, cpu_all_mask);

	cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);



	raw_spin_lock_init(&global_trace.start_lock);
@@ -6441,7 +6444,7 @@ __init static int tracer_alloc_buffers(void) 
#ifdef CONFIG_TRACER_MAX_TRACE

	free_percpu(global_trace.max_buffer.data);

#endif

	free_cpumask_var(tracing_cpumask);

	free_cpumask_var(global_trace.tracing_cpumask);

out_free_buffer_mask:

	free_cpumask_var(tracing_buffer_mask);

out:

kernel/trace/trace.h

+1 −0
Original line number Diff line number Diff line
@@ -206,6 +206,7 @@ struct trace_array { 
	struct dentry		*event_dir;

	struct list_head	systems;

	struct list_head	events;

	cpumask_var_t		tracing_cpumask; /* only trace on set CPUs */

	int			ref;

};