Merge branches 'tracing/profiling', 'tracing/options' and 'tracing/urgent' into tracing/core

kernel/trace/trace.c

@@ -43,6 +43,20 @@
 unsigned long __read_mostly	tracing_max_latency = (cycle_t)ULONG_MAX;
 unsigned long __read_mostly	tracing_thresh;
 
+/* For tracers that don't implement custom flags */
+static struct tracer_opt dummy_tracer_opt[] = {
+	{ }
+};
+
+static struct tracer_flags dummy_tracer_flags = {
+	.val = 0,
+	.opts = dummy_tracer_opt
+};
+
+static int dummy_set_flag(u32 old_flags, u32 bit, int set)
+{
+	return 0;
+}
 
 /*
  * Kill all tracing for good (never come back).
@@ -537,6 +551,14 @@ int register_tracer(struct tracer *type)
 		}
 	}
 
+	if (!type->set_flag)
+		type->set_flag = &dummy_set_flag;
+	if (!type->flags)
+		type->flags = &dummy_tracer_flags;
+	else
+		if (!type->flags->opts)
+			type->flags->opts = dummy_tracer_opt;
+
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 	if (type->selftest) {
 		struct tracer *saved_tracer = current_trace;
@@ -840,6 +862,7 @@ static void __trace_function_return(struct trace_array *tr,
 	entry->parent_ip	= trace->ret;
 	entry->rettime		= trace->rettime;
 	entry->calltime		= trace->calltime;
+	entry->overrun		= trace->overrun;
 	ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags);
 }
 #endif
@@ -2436,10 +2459,13 @@ static ssize_t
 tracing_trace_options_read(struct file *filp, char __user *ubuf,
 		       size_t cnt, loff_t *ppos)
 {
+	int i;
 	char *buf;
 	int r = 0;
 	int len = 0;
-	int i;
+	u32 tracer_flags = current_trace->flags->val;
+	struct tracer_opt *trace_opts = current_trace->flags->opts;
+
 
 	/* calulate max size */
 	for (i = 0; trace_options[i]; i++) {
@@ -2447,6 +2473,15 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf,
 		len += 3; /* "no" and space */
 	}
 
+	/*
+	 * Increase the size with names of options specific
+	 * of the current tracer.
+	 */
+	for (i = 0; trace_opts[i].name; i++) {
+		len += strlen(trace_opts[i].name);
+		len += 3; /* "no" and space */
+	}
+
 	/* +2 for \n and \0 */
 	buf = kmalloc(len + 2, GFP_KERNEL);
 	if (!buf)
@@ -2459,6 +2494,15 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf,
 			r += sprintf(buf + r, "no%s ", trace_options[i]);
 	}
 
+	for (i = 0; trace_opts[i].name; i++) {
+		if (tracer_flags & trace_opts[i].bit)
+			r += sprintf(buf + r, "%s ",
+				trace_opts[i].name);
+		else
+			r += sprintf(buf + r, "no%s ",
+				trace_opts[i].name);
+	}
+
 	r += sprintf(buf + r, "\n");
 	WARN_ON(r >= len + 2);
 
@@ -2469,6 +2513,40 @@ tracing_trace_options_read(struct file *filp, char __user *ubuf,
 	return r;
 }
 
+/* Try to assign a tracer specific option */
+static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
+{
+	struct tracer_flags *trace_flags = trace->flags;
+	struct tracer_opt *opts = NULL;
+	int ret = 0, i = 0;
+	int len;
+
+	for (i = 0; trace_flags->opts[i].name; i++) {
+		opts = &trace_flags->opts[i];
+		len = strlen(opts->name);
+
+		if (strncmp(cmp, opts->name, len) == 0) {
+			ret = trace->set_flag(trace_flags->val,
+				opts->bit, !neg);
+			break;
+		}
+	}
+	/* Not found */
+	if (!trace_flags->opts[i].name)
+		return -EINVAL;
+
+	/* Refused to handle */
+	if (ret)
+		return ret;
+
+	if (neg)
+		trace_flags->val &= ~opts->bit;
+	else
+		trace_flags->val |= opts->bit;
+
+	return 0;
+}
+
 static ssize_t
 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 			size_t cnt, loff_t *ppos)
@@ -2476,6 +2554,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 	char buf[64];
 	char *cmp = buf;
 	int neg = 0;
+	int ret;
 	int i;
 
 	if (cnt >= sizeof(buf))
@@ -2502,11 +2581,13 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 			break;
 		}
 	}
-	/*
-	 * If no option could be set, return an error:
-	 */
-	if (!trace_options[i])
-		return -EINVAL;
+
+	/* If no option could be set, test the specific tracer options */
+	if (!trace_options[i]) {
+		ret = set_tracer_option(current_trace, cmp, neg);
+		if (ret)
+			return ret;
+	}
 
 	filp->f_pos += cnt;
 

kernel/trace/trace.h

@@ -60,6 +60,7 @@ struct ftrace_ret_entry {
 	unsigned long		parent_ip;
 	unsigned long long	calltime;
 	unsigned long long	rettime;
+	unsigned long		overrun;
 };
 extern struct tracer boot_tracer;
 
@@ -259,6 +260,29 @@ enum print_line_t {
 	TRACE_TYPE_UNHANDLED	= 2	/* Relay to other output functions */
 };
 
+
+/*
+ * An option specific to a tracer. This is a boolean value.
+ * The bit is the bit index that sets its value on the
+ * flags value in struct tracer_flags.
+ */
+struct tracer_opt {
+	const char 	*name; /* Will appear on the trace_options file */
+	u32 		bit; /* Mask assigned in val field in tracer_flags */
+};
+
+/*
+ * The set of specific options for a tracer. Your tracer
+ * have to set the initial value of the flags val.
+ */
+struct tracer_flags {
+	u32			val;
+	struct tracer_opt 	*opts;
+};
+
+/* Makes more easy to define a tracer opt */
+#define TRACER_OPT(s, b)	.name = #s, .bit = b
+
 /*
  * A specific tracer, represented by methods that operate on a trace array:
  */
@@ -280,8 +304,11 @@ struct tracer {
 					    struct trace_array *tr);
 #endif
 	enum print_line_t	(*print_line)(struct trace_iterator *iter);
+	/* If you handled the flag setting, return 0 */
+	int			(*set_flag)(u32 old_flags, u32 bit, int set);
 	struct tracer		*next;
 	int			print_max;
+	struct tracer_flags 	*flags;
 };
 
 struct trace_seq {

kernel/trace/trace_functions_return.c

@@ -14,6 +14,19 @@
 #include "trace.h"
 
 
+#define TRACE_RETURN_PRINT_OVERRUN	0x1
+static struct tracer_opt trace_opts[] = {
+	/* Display overruns or not */
+	{ TRACER_OPT(overrun, TRACE_RETURN_PRINT_OVERRUN) },
+	{ } /* Empty entry */
+};
+
+static struct tracer_flags tracer_flags = {
+	.val = 0, /* Don't display overruns by default */
+	.opts = trace_opts
+};
+
+
 static int return_trace_init(struct trace_array *tr)
 {
 	int cpu;
@@ -42,26 +55,39 @@ print_return_function(struct trace_iterator *iter)
 		ret = trace_seq_printf(s, "%pF -> ", (void *)field->parent_ip);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
+
 		ret = seq_print_ip_sym(s, field->ip,
 					trace_flags & TRACE_ITER_SYM_MASK);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
-		ret = trace_seq_printf(s, " (%llu ns)\n",
+
+		ret = trace_seq_printf(s, " (%llu ns)",
 					field->rettime - field->calltime);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
-		else
-			return TRACE_TYPE_HANDLED;
+
+		if (tracer_flags.val & TRACE_RETURN_PRINT_OVERRUN) {
+			ret = trace_seq_printf(s, " (Overruns: %lu)",
+						field->overrun);
+			if (!ret)
+				return TRACE_TYPE_PARTIAL_LINE;
+		}
+
+		ret = trace_seq_printf(s, "\n");
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+
+		return TRACE_TYPE_HANDLED;
 	}
 	return TRACE_TYPE_UNHANDLED;
 }
 
-static struct tracer return_trace __read_mostly =
-{
+static struct tracer return_trace __read_mostly = {
 	.name	     = "return",
 	.init	     = return_trace_init,
 	.reset	     = return_trace_reset,
-	.print_line = print_return_function
+	.print_line = print_return_function,
+	.flags		= &tracer_flags,
 };
 
 static __init int init_return_trace(void)

kernel/trace/trace_nop.c

@@ -12,6 +12,27 @@
 
 #include "trace.h"
 
+/* Our two options */
+enum {
+	TRACE_NOP_OPT_ACCEPT = 0x1,
+	TRACE_NOP_OPT_REFUSE = 0x2
+};
+
+/* Options for the tracer (see trace_options file) */
+static struct tracer_opt nop_opts[] = {
+	/* Option that will be accepted by set_flag callback */
+	{ TRACER_OPT(test_nop_accept, TRACE_NOP_OPT_ACCEPT) },
+	/* Option that will be refused by set_flag callback */
+	{ TRACER_OPT(test_nop_refuse, TRACE_NOP_OPT_REFUSE) },
+	{ } /* Always set a last empty entry */
+};
+
+static struct tracer_flags nop_flags = {
+	/* You can check your flags value here when you want. */
+	.val = 0, /* By default: all flags disabled */
+	.opts = nop_opts
+};
+
 static struct trace_array	*ctx_trace;
 
 static void start_nop_trace(struct trace_array *tr)
@@ -41,6 +62,35 @@ static void nop_trace_reset(struct trace_array *tr)
 	stop_nop_trace(tr);
 }
 
+/* It only serves as a signal handler and a callback to
+ * accept or refuse tthe setting of a flag.
+ * If you don't implement it, then the flag setting will be
+ * automatically accepted.
+ */
+static int nop_set_flag(u32 old_flags, u32 bit, int set)
+{
+	/*
+	 * Note that you don't need to update nop_flags.val yourself.
+	 * The tracing Api will do it automatically if you return 0
+	 */
+	if (bit == TRACE_NOP_OPT_ACCEPT) {
+		printk(KERN_DEBUG "nop_test_accept flag set to %d: we accept."
+			" Now cat trace_options to see the result\n",
+			set);
+		return 0;
+	}
+
+	if (bit == TRACE_NOP_OPT_REFUSE) {
+		printk(KERN_DEBUG "nop_test_refuse flag set to %d: we refuse."
+			"Now cat trace_options to see the result\n",
+			set);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+
 struct tracer nop_trace __read_mostly =
 {
 	.name		= "nop",
@@ -49,5 +99,7 @@ struct tracer nop_trace __read_mostly =
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest	= trace_selftest_startup_nop,
 #endif
+	.flags		= &nop_flags,
+	.set_flag	= nop_set_flag
 };
 

kernel/trace/trace_stack.c

@@ -180,11 +180,16 @@ static struct file_operations stack_max_size_fops = {
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
-	long i = (long)m->private;
+	long i;
 
 	(*pos)++;
 
-	i++;
+	if (v == SEQ_START_TOKEN)
+		i = 0;
+	else {
+		i = *(long *)v;
+		i++;
+	}
 
 	if (i >= max_stack_trace.nr_entries ||
 	    stack_dump_trace[i] == ULONG_MAX)
@@ -197,12 +202,15 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
-	void *t = &m->private;
+	void *t = SEQ_START_TOKEN;
 	loff_t l = 0;
 
 	local_irq_disable();
 	__raw_spin_lock(&max_stack_lock);
 
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
 	for (; t && l < *pos; t = t_next(m, t, &l))
 		;
 
@@ -231,10 +239,10 @@ static int trace_lookup_stack(struct seq_file *m, long i)
 
 static int t_show(struct seq_file *m, void *v)
 {
-	long i = *(long *)v;
+	long i;
 	int size;
 
-	if (i < 0) {
+	if (v == SEQ_START_TOKEN) {
 		seq_printf(m, "        Depth   Size      Location"
 			   "    (%d entries)\n"
 			   "        -----   ----      --------\n",
@@ -242,6 +250,8 @@ static int t_show(struct seq_file *m, void *v)
 		return 0;
 	}
 
+	i = *(long *)v;
+
 	if (i >= max_stack_trace.nr_entries ||
 	    stack_dump_trace[i] == ULONG_MAX)
 		return 0;
@@ -271,10 +281,6 @@ static int stack_trace_open(struct inode *inode, struct file *file)
 	int ret;
 
 	ret = seq_open(file, &stack_trace_seq_ops);
-	if (!ret) {
-		struct seq_file *m = file->private_data;
-		m->private = (void *)-1;
-	}
 
 	return ret;
 }