X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Ftrace%2Ftrace_stat.c;h=a4bb239eb9874a1a6efe7703a303a7e103c4c977;hb=f653398c86a1c104f0992bd788dd4bb065449be4;hp=6f194a33a64a4d2c2d1a748478e49b2a467a5e28;hpb=dbd0b4b33074aa6b7832a9d9a5bd985eca5c1aa2;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 6f194a3..a4bb239 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -1,7 +1,7 @@
 /*
  * Infrastructure for statistic tracing (histogram output).
  *
- * Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
+ * Copyright (C) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
  *
  * Based on the code from trace_branch.c which is
  * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
@@ -10,219 +10,288 @@
 
 
 #include <linux/list.h>
-#include <linux/seq_file.h>
+#include <linux/rbtree.h>
 #include <linux/debugfs.h>
+#include "trace_stat.h"
 #include "trace.h"
 
 
-/* List of stat entries from a tracer */
-struct trace_stat_list {
-	struct list_head list;
-	void *stat;
+/*
+ * List of stat red-black nodes from a tracer
+ * We use a such tree to sort quickly the stat
+ * entries from the tracer.
+ */
+struct stat_node {
+	struct rb_node		node;
+	void			*stat;
 };
 
-static struct trace_stat_list stat_list;
+/* A stat session is the stats output in one file */
+struct stat_session {
+	struct list_head	session_list;
+	struct tracer_stat	*ts;
+	struct rb_root		stat_root;
+	struct mutex		stat_mutex;
+	struct dentry		*file;
+};
 
-/*
- * This is a copy of the current tracer to avoid racy
- * and dangerous output while the current tracer is
- * switched.
- */
-static struct tracer current_tracer;
+/* All of the sessions currently in use. Each stat file embed one session */
+static LIST_HEAD(all_stat_sessions);
+static DEFINE_MUTEX(all_stat_sessions_mutex);
+
+/* The root directory for all stat files */
+static struct dentry		*stat_dir;
 
 /*
- * Protect both the current tracer and the global
- * stat list.
+ * Iterate through the rbtree using a post order traversal path
+ * to release the next node.
+ * It won't necessary release one at each iteration
+ * but it will at least advance closer to the next one
+ * to be released.
  */
-static DEFINE_MUTEX(stat_list_mutex);
-
+static struct rb_node *release_next(struct tracer_stat *ts,
+				    struct rb_node *node)
+{
+	struct stat_node *snode;
+	struct rb_node *parent = rb_parent(node);
+
+	if (node->rb_left)
+		return node->rb_left;
+	else if (node->rb_right)
+		return node->rb_right;
+	else {
+		if (!parent)
+			;
+		else if (parent->rb_left == node)
+			parent->rb_left = NULL;
+		else
+			parent->rb_right = NULL;
+
+		snode = container_of(node, struct stat_node, node);
+		if (ts->stat_release)
+			ts->stat_release(snode->stat);
+		kfree(snode);
+
+		return parent;
+	}
+}
 
-static void reset_stat_list(void)
+static void __reset_stat_session(struct stat_session *session)
 {
-	struct trace_stat_list *node;
-	struct list_head *next;
+	struct rb_node *node = session->stat_root.rb_node;
 
-	if (list_empty(&stat_list.list))
-		return;
+	while (node)
+		node = release_next(session->ts, node);
 
-	node = list_entry(stat_list.list.next, struct trace_stat_list, list);
-	next = node->list.next;
+	session->stat_root = RB_ROOT;
+}
 
-	while (&node->list != next) {
-		kfree(node);
-		node = list_entry(next, struct trace_stat_list, list);
-	}
-	kfree(node);
+static void reset_stat_session(struct stat_session *session)
+{
+	mutex_lock(&session->stat_mutex);
+	__reset_stat_session(session);
+	mutex_unlock(&session->stat_mutex);
+}
 
-	INIT_LIST_HEAD(&stat_list.list);
+static void destroy_session(struct stat_session *session)
+{
+	debugfs_remove(session->file);
+	__reset_stat_session(session);
+	mutex_destroy(&session->stat_mutex);
+	kfree(session);
 }
 
-void init_tracer_stat(struct tracer *trace)
+typedef int (*cmp_stat_t)(void *, void *);
+
+static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)
 {
-	mutex_lock(&stat_list_mutex);
-	current_tracer = *trace;
-	mutex_unlock(&stat_list_mutex);
+	struct rb_node **new = &(root->rb_node), *parent = NULL;
+	struct stat_node *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->stat = stat;
+
+	/*
+	 * Figure out where to put new node
+	 * This is a descendent sorting
+	 */
+	while (*new) {
+		struct stat_node *this;
+		int result;
+
+		this = container_of(*new, struct stat_node, node);
+		result = cmp(data->stat, this->stat);
+
+		parent = *new;
+		if (result >= 0)
+			new = &((*new)->rb_left);
+		else
+			new = &((*new)->rb_right);
+	}
+
+	rb_link_node(&data->node, parent, new);
+	rb_insert_color(&data->node, root);
+	return 0;
 }
 
 /*
  * For tracers that don't provide a stat_cmp callback.
- * This one will force an immediate insertion on tail of
- * the list.
+ * This one will force an insertion as right-most node
+ * in the rbtree.
  */
 static int dummy_cmp(void *p1, void *p2)
 {
-	return 1;
+	return -1;
 }
 
 /*
- * Initialize the stat list at each trace_stat file opening.
+ * Initialize the stat rbtree at each trace_stat file opening.
  * All of these copies and sorting are required on all opening
  * since the stats could have changed between two file sessions.
  */
-static int stat_seq_init(void)
+static int stat_seq_init(struct stat_session *session)
 {
-	struct trace_stat_list *iter_entry, *new_entry;
-	void *prev_stat;
+	struct tracer_stat *ts = session->ts;
+	struct rb_root *root = &session->stat_root;
+	void *stat;
 	int ret = 0;
 	int i;
 
-	mutex_lock(&stat_list_mutex);
-	reset_stat_list();
-
-	if (!current_tracer.stat_start || !current_tracer.stat_next ||
-					!current_tracer.stat_show)
-		goto exit;
+	mutex_lock(&session->stat_mutex);
+	__reset_stat_session(session);
 
-	if (!current_tracer.stat_cmp)
-		current_tracer.stat_cmp = dummy_cmp;
+	if (!ts->stat_cmp)
+		ts->stat_cmp = dummy_cmp;
 
-	/*
-	 * The first entry. Actually this is the second, but the first
-	 * one (the stat_list head) is pointless.
-	 */
-	new_entry = kmalloc(sizeof(struct trace_stat_list), GFP_KERNEL);
-	if (!new_entry) {
-		ret = -ENOMEM;
+	stat = ts->stat_start(ts);
+	if (!stat)
 		goto exit;
-	}
-
-	INIT_LIST_HEAD(&new_entry->list);
-	list_add(&new_entry->list, &stat_list.list);
-	new_entry->stat = current_tracer.stat_start();
 
-	prev_stat = new_entry->stat;
+	ret = insert_stat(root, stat, ts->stat_cmp);
+	if (ret)
+		goto exit;
 
 	/*
-	 * Iterate over the tracer stat entries and store them in a sorted
-	 * list.
+	 * Iterate over the tracer stat entries and store them in an rbtree.
 	 */
 	for (i = 1; ; i++) {
-		new_entry = kmalloc(sizeof(struct trace_stat_list), GFP_KERNEL);
-		if (!new_entry) {
-			ret = -ENOMEM;
-			goto exit_free_list;
-		}
-
-		INIT_LIST_HEAD(&new_entry->list);
-		new_entry->stat = current_tracer.stat_next(prev_stat, i);
+		stat = ts->stat_next(stat, i);
 
 		/* End of insertion */
-		if (!new_entry->stat)
+		if (!stat)
 			break;
 
-		list_for_each_entry(iter_entry, &stat_list.list, list) {
-			/* Insertion with a descendent sorting */
-			if (current_tracer.stat_cmp(new_entry->stat,
-						iter_entry->stat) > 0) {
-
-				list_add_tail(&new_entry->list,
-						&iter_entry->list);
-				break;
-
-			/* The current smaller value */
-			} else if (list_is_last(&iter_entry->list,
-						&stat_list.list)) {
-				list_add(&new_entry->list, &iter_entry->list);
-				break;
-			}
-		}
-
-		prev_stat = new_entry->stat;
+		ret = insert_stat(root, stat, ts->stat_cmp);
+		if (ret)
+			goto exit_free_rbtree;
 	}
+
 exit:
-	mutex_unlock(&stat_list_mutex);
+	mutex_unlock(&session->stat_mutex);
 	return ret;
 
-exit_free_list:
-	reset_stat_list();
-	mutex_unlock(&stat_list_mutex);
+exit_free_rbtree:
+	__reset_stat_session(session);
+	mutex_unlock(&session->stat_mutex);
 	return ret;
 }
 
 
 static void *stat_seq_start(struct seq_file *s, loff_t *pos)
 {
-	struct trace_stat_list *l = (struct trace_stat_list *)s->private;
+	struct stat_session *session = s->private;
+	struct rb_node *node;
+	int n = *pos;
+	int i;
 
-	/* Prevent from tracer switch or stat_list modification */
-	mutex_lock(&stat_list_mutex);
+	/* Prevent from tracer switch or rbtree modification */
+	mutex_lock(&session->stat_mutex);
 
 	/* If we are in the beginning of the file, print the headers */
-	if (!*pos && current_tracer.stat_headers)
-		current_tracer.stat_headers(s);
+	if (session->ts->stat_headers) {
+		if (n == 0)
+			return SEQ_START_TOKEN;
+		n--;
+	}
+
+	node = rb_first(&session->stat_root);
+	for (i = 0; node && i < n; i++)
+		node = rb_next(node);
 
-	return seq_list_start(&l->list, *pos);
+	return node;
 }
 
 static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos)
 {
-	struct trace_stat_list *l = (struct trace_stat_list *)s->private;
+	struct stat_session *session = s->private;
+	struct rb_node *node = p;
+
+	(*pos)++;
 
-	return seq_list_next(p, &l->list, pos);
+	if (p == SEQ_START_TOKEN)
+		return rb_first(&session->stat_root);
+
+	return rb_next(node);
 }
 
-static void stat_seq_stop(struct seq_file *m, void *p)
+static void stat_seq_stop(struct seq_file *s, void *p)
 {
-	mutex_unlock(&stat_list_mutex);
+	struct stat_session *session = s->private;
+	mutex_unlock(&session->stat_mutex);
 }
 
 static int stat_seq_show(struct seq_file *s, void *v)
 {
-	struct trace_stat_list *l = list_entry(v, struct trace_stat_list, list);
-	return current_tracer.stat_show(s, l->stat);
+	struct stat_session *session = s->private;
+	struct stat_node *l = container_of(v, struct stat_node, node);
+
+	if (v == SEQ_START_TOKEN)
+		return session->ts->stat_headers(s);
+
+	return session->ts->stat_show(s, l->stat);
 }
 
 static const struct seq_operations trace_stat_seq_ops = {
-	.start = stat_seq_start,
-	.next = stat_seq_next,
-	.stop = stat_seq_stop,
-	.show = stat_seq_show
+	.start		= stat_seq_start,
+	.next		= stat_seq_next,
+	.stop		= stat_seq_stop,
+	.show		= stat_seq_show
 };
 
+/* The session stat is refilled and resorted at each stat file opening */
 static int tracing_stat_open(struct inode *inode, struct file *file)
 {
 	int ret;
+	struct seq_file *m;
+	struct stat_session *session = inode->i_private;
+
+	ret = stat_seq_init(session);
+	if (ret)
+		return ret;
 
 	ret = seq_open(file, &trace_stat_seq_ops);
-	if (!ret) {
-		struct seq_file *m = file->private_data;
-		m->private = &stat_list;
-		ret = stat_seq_init();
+	if (ret) {
+		reset_stat_session(session);
+		return ret;
 	}
 
+	m = file->private_data;
+	m->private = session;
 	return ret;
 }
 
-
 /*
- * Avoid consuming memory with our now useless list.
+ * Avoid consuming memory with our now useless rbtree.
  */
 static int tracing_stat_release(struct inode *i, struct file *f)
 {
-	mutex_lock(&stat_list_mutex);
-	reset_stat_list();
-	mutex_unlock(&stat_list_mutex);
-	return 0;
+	struct stat_session *session = i->i_private;
+
+	reset_stat_session(session);
+
+	return seq_release(i, f);
 }
 
 static const struct file_operations tracing_stat_fops = {
@@ -232,20 +301,87 @@ static const struct file_operations tracing_stat_fops = {
 	.release	= tracing_stat_release
 };
 
-static int __init tracing_stat_init(void)
+static int tracing_stat_init(void)
 {
 	struct dentry *d_tracing;
-	struct dentry *entry;
 
-	INIT_LIST_HEAD(&stat_list.list);
 	d_tracing = tracing_init_dentry();
 
-	entry = debugfs_create_file("trace_stat", 0444, d_tracing,
-					NULL,
-				    &tracing_stat_fops);
-	if (!entry)
+	stat_dir = debugfs_create_dir("trace_stat", d_tracing);
+	if (!stat_dir)
 		pr_warning("Could not create debugfs "
 			   "'trace_stat' entry\n");
 	return 0;
 }
-fs_initcall(tracing_stat_init);
+
+static int init_stat_file(struct stat_session *session)
+{
+	if (!stat_dir && tracing_stat_init())
+		return -ENODEV;
+
+	session->file = debugfs_create_file(session->ts->name, 0644,
+					    stat_dir,
+					    session, &tracing_stat_fops);
+	if (!session->file)
+		return -ENOMEM;
+	return 0;
+}
+
+int register_stat_tracer(struct tracer_stat *trace)
+{
+	struct stat_session *session, *node;
+	int ret;
+
+	if (!trace)
+		return -EINVAL;
+
+	if (!trace->stat_start || !trace->stat_next || !trace->stat_show)
+		return -EINVAL;
+
+	/* Already registered? */
+	mutex_lock(&all_stat_sessions_mutex);
+	list_for_each_entry(node, &all_stat_sessions, session_list) {
+		if (node->ts == trace) {
+			mutex_unlock(&all_stat_sessions_mutex);
+			return -EINVAL;
+		}
+	}
+	mutex_unlock(&all_stat_sessions_mutex);
+
+	/* Init the session */
+	session = kzalloc(sizeof(*session), GFP_KERNEL);
+	if (!session)
+		return -ENOMEM;
+
+	session->ts = trace;
+	INIT_LIST_HEAD(&session->session_list);
+	mutex_init(&session->stat_mutex);
+
+	ret = init_stat_file(session);
+	if (ret) {
+		destroy_session(session);
+		return ret;
+	}
+
+	/* Register */
+	mutex_lock(&all_stat_sessions_mutex);
+	list_add_tail(&session->session_list, &all_stat_sessions);
+	mutex_unlock(&all_stat_sessions_mutex);
+
+	return 0;
+}
+
+void unregister_stat_tracer(struct tracer_stat *trace)
+{
+	struct stat_session *node, *tmp;
+
+	mutex_lock(&all_stat_sessions_mutex);
+	list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
+		if (node->ts == trace) {
+			list_del(&node->session_list);
+			destroy_session(node);
+			break;
+		}
+	}
+	mutex_unlock(&all_stat_sessions_mutex);
+}