Merge branch 'perf/core' into perf/uprobes

Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 116 insertions, 3 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a3f1bc5d2a0..ed7b5d1e12f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -36,6 +36,7 @@
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/poll.h>
+#include <linux/nmi.h>
 #include <linux/fs.h>
 
 #include "trace.h"
@@ -352,6 +353,59 @@ static void wakeup_work_handler(struct work_struct *work)
 static DECLARE_DELAYED_WORK(wakeup_work, wakeup_work_handler);
 
 /**
+ * tracing_on - enable tracing buffers
+ *
+ * This function enables tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+	if (global_trace.buffer)
+		ring_buffer_record_on(global_trace.buffer);
+	/*
+	 * This flag is only looked at when buffers haven't been
+	 * allocated yet. We don't really care about the race
+	 * between setting this flag and actually turning
+	 * on the buffer.
+	 */
+	global_trace.buffer_disabled = 0;
+}
+EXPORT_SYMBOL_GPL(tracing_on);
+
+/**
+ * tracing_off - turn off tracing buffers
+ *
+ * This function stops the tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+	if (global_trace.buffer)
+		ring_buffer_record_on(global_trace.buffer);
+	/*
+	 * This flag is only looked at when buffers haven't been
+	 * allocated yet. We don't really care about the race
+	 * between setting this flag and actually turning
+	 * on the buffer.
+	 */
+	global_trace.buffer_disabled = 1;
+}
+EXPORT_SYMBOL_GPL(tracing_off);
+
+/**
+ * tracing_is_on - show state of ring buffers enabled
+ */
+int tracing_is_on(void)
+{
+	if (global_trace.buffer)
+		return ring_buffer_record_is_on(global_trace.buffer);
+	return !global_trace.buffer_disabled;
+}
+EXPORT_SYMBOL_GPL(tracing_is_on);
+
+/**
  * trace_wake_up - wake up tasks waiting for trace input
  *
  * Schedules a delayed work to wake up any task that is blocked on the
@@ -1644,6 +1698,7 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
 	int cpu_file = iter->cpu_file;
 	u64 next_ts = 0, ts;
 	int next_cpu = -1;
+	int next_size = 0;
 	int cpu;
 
 	/*
@@ -1675,9 +1730,12 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
 			next_cpu = cpu;
 			next_ts = ts;
 			next_lost = lost_events;
+			next_size = iter->ent_size;
 		}
 	}
 
+	iter->ent_size = next_size;
+
 	if (ent_cpu)
 		*ent_cpu = next_cpu;
 
@@ -2764,12 +2822,12 @@ static const char readme_msg[] =
 	"tracing mini-HOWTO:\n\n"
 	"# mount -t debugfs nodev /sys/kernel/debug\n\n"
 	"# cat /sys/kernel/debug/tracing/available_tracers\n"
-	"wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
+	"wakeup wakeup_rt preemptirqsoff preemptoff irqsoff function nop\n\n"
 	"# cat /sys/kernel/debug/tracing/current_tracer\n"
 	"nop\n"
-	"# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
+	"# echo wakeup > /sys/kernel/debug/tracing/current_tracer\n"
 	"# cat /sys/kernel/debug/tracing/current_tracer\n"
-	"sched_switch\n"
+	"wakeup\n"
 	"# cat /sys/kernel/debug/tracing/trace_options\n"
 	"noprint-parent nosym-offset nosym-addr noverbose\n"
 	"# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
@@ -4567,6 +4625,55 @@ static __init void create_trace_options_dir(void)
 		create_trace_option_core_file(trace_options[i], i);
 }
 
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+	       size_t cnt, loff_t *ppos)
+{
+	struct ring_buffer *buffer = filp->private_data;
+	char buf[64];
+	int r;
+
+	if (buffer)
+		r = ring_buffer_record_is_on(buffer);
+	else
+		r = 0;
+
+	r = sprintf(buf, "%d\n", r);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos)
+{
+	struct ring_buffer *buffer = filp->private_data;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (buffer) {
+		if (val)
+			ring_buffer_record_on(buffer);
+		else
+			ring_buffer_record_off(buffer);
+	}
+
+	(*ppos)++;
+
+	return cnt;
+}
+
+static const struct file_operations rb_simple_fops = {
+	.open		= tracing_open_generic,
+	.read		= rb_simple_read,
+	.write		= rb_simple_write,
+	.llseek		= default_llseek,
+};
+
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
@@ -4626,6 +4733,9 @@ static __init int tracer_init_debugfs(void)
 	trace_create_file("trace_clock", 0644, d_tracer, NULL,
 			  &trace_clock_fops);
 
+	trace_create_file("tracing_on", 0644, d_tracer,
+			    global_trace.buffer, &rb_simple_fops);
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
 			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
@@ -4798,6 +4908,7 @@ __ftrace_dump(bool disable_tracing, enum ftrace_dump_mode oops_dump_mode)
 			if (ret != TRACE_TYPE_NO_CONSUME)
 				trace_consume(&iter);
 		}
+		touch_nmi_watchdog();
 
 		trace_printk_seq(&iter.seq);
 	}
@@ -4863,6 +4974,8 @@ __init static int tracer_alloc_buffers(void)
 		goto out_free_cpumask;
 	}
 	global_trace.entries = ring_buffer_size(global_trace.buffer);
+	if (global_trace.buffer_disabled)
+		tracing_off();
 
 
 #ifdef CONFIG_TRACER_MAX_TRACE