1 files changed, 128 insertions, 80 deletions

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index acdebd771a9..c00643733f4 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>
@@ -10,22 +10,27 @@
 
 
 #include <linux/list.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;
+/*
+ * 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;
 };
 
 /* A stat session is the stats output in one file */
-struct tracer_stat_session {
+struct stat_session {
         struct list_head        session_list;
         struct tracer_stat      *ts;
-        struct list_head        stat_list;
+        struct rb_root          stat_root;
         struct mutex            stat_mutex;
         struct dentry           *file;
 };
@@ -37,18 +42,48 @@ static DEFINE_MUTEX(all_stat_sessions_mutex);
 /* The root directory for all stat files */
 static struct dentry            *stat_dir;
 
+/*
+ * 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 struct rb_node *release_next(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);
+                kfree(snode);
+
+                return parent;
+        }
+}
 
-static void reset_stat_session(struct tracer_stat_session *session)
+static void reset_stat_session(struct stat_session *session)
 {
-        struct trace_stat_list *node, *next;
+        struct rb_node *node = session->stat_root.rb_node;
 
-        list_for_each_entry_safe(node, next, &session->stat_list, list)
-                kfree(node);
+        while (node)
+                node = release_next(node);
 
-        INIT_LIST_HEAD(&session->stat_list);
+        session->stat_root = RB_ROOT;
 }
 
-static void destroy_session(struct tracer_stat_session *session)
+static void destroy_session(struct stat_session *session)
 {
         debugfs_remove(session->file);
         reset_stat_session(session);
@@ -56,25 +91,60 @@ static void destroy_session(struct tracer_stat_session *session)
         kfree(session);
 }
 
+typedef int (*cmp_stat_t)(void *, void *);
+
+static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp)
+{
+        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(struct tracer_stat_session *session)
+static int stat_seq_init(struct stat_session *session)
 {
-        struct trace_stat_list *iter_entry, *new_entry;
         struct tracer_stat *ts = session->ts;
+        struct rb_root *root = &session->stat_root;
         void *stat;
         int ret = 0;
         int i;
@@ -85,29 +155,16 @@ static int stat_seq_init(struct tracer_stat_session *session)
         if (!ts->stat_cmp)
                 ts->stat_cmp = dummy_cmp;
 
-        stat = ts->stat_start();
+        stat = ts->stat_start(ts);
         if (!stat)
                 goto exit;
 
-        /*
-         * 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;
+        ret = insert_stat(root, stat, ts->stat_cmp);
+        if (ret)
                 goto exit;
-        }
-
-        INIT_LIST_HEAD(&new_entry->list);
-
-        list_add(&new_entry->list, &session->stat_list);
-
-        new_entry->stat = stat;
 
         /*
-         * 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++) {
                 stat = ts->stat_next(stat, i);
@@ -116,36 +173,16 @@ static int stat_seq_init(struct tracer_stat_session *session)
                 if (!stat)
                         break;
 
-                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 = stat;
-
-                list_for_each_entry_reverse(iter_entry, &session->stat_list,
-                                list) {
-
-                        /* Insertion with a descendent sorting */
-                        if (ts->stat_cmp(iter_entry->stat,
-                                        new_entry->stat) >= 0) {
-
-                                list_add(&new_entry->list, &iter_entry->list);
-                                break;
-                        }
-                }
-
-                /* The current larger value */
-                if (list_empty(&new_entry->list))
-                        list_add(&new_entry->list, &session->stat_list);
+                ret = insert_stat(root, stat, ts->stat_cmp);
+                if (ret)
+                        goto exit_free_rbtree;
         }
+
 exit:
         mutex_unlock(&session->stat_mutex);
         return ret;
 
-exit_free_list:
+exit_free_rbtree:
         reset_stat_session(session);
         mutex_unlock(&session->stat_mutex);
         return ret;
@@ -154,38 +191,51 @@ exit_free_list:
 
 static void *stat_seq_start(struct seq_file *s, loff_t *pos)
 {
-        struct tracer_stat_session *session = s->private;
+        struct stat_session *session = s->private;
+        struct rb_node *node;
+        int i;
 
-        /* Prevent from tracer switch or stat_list modification */
+        /* 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 && session->ts->stat_headers)
+        if (!*pos && session->ts->stat_headers) {
+                (*pos)++;
                 return SEQ_START_TOKEN;
+        }
 
-        return seq_list_start(&session->stat_list, *pos);
+        node = rb_first(&session->stat_root);
+        for (i = 0; node && i < *pos; i++)
+                node = rb_next(node);
+
+        (*pos)++;
+
+        return node;
 }
 
 static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos)
 {
-        struct tracer_stat_session *session = s->private;
+        struct stat_session *session = s->private;
+        struct rb_node *node = p;
+
+        (*pos)++;
 
         if (p == SEQ_START_TOKEN)
-                return seq_list_start(&session->stat_list, *pos);
+                return rb_first(&session->stat_root);
 
-        return seq_list_next(p, &session->stat_list, pos);
+        return rb_next(node);
 }
 
 static void stat_seq_stop(struct seq_file *s, void *p)
 {
-        struct tracer_stat_session *session = s->private;
+        struct stat_session *session = s->private;
         mutex_unlock(&session->stat_mutex);
 }
 
 static int stat_seq_show(struct seq_file *s, void *v)
 {
-        struct tracer_stat_session *session = s->private;
-        struct trace_stat_list *l = list_entry(v, struct trace_stat_list, list);
+        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);
@@ -205,7 +255,7 @@ static int tracing_stat_open(struct inode *inode, struct file *file)
 {
         int ret;
 
-        struct tracer_stat_session *session = inode->i_private;
+        struct stat_session *session = inode->i_private;
 
         ret = seq_open(file, &trace_stat_seq_ops);
         if (!ret) {
@@ -218,11 +268,11 @@ static int tracing_stat_open(struct inode *inode, struct file *file)
 }
 
 /*
- * 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)
 {
-        struct tracer_stat_session *session = i->i_private;
+        struct stat_session *session = i->i_private;
 
         mutex_lock(&session->stat_mutex);
         reset_stat_session(session);
@@ -251,7 +301,7 @@ static int tracing_stat_init(void)
         return 0;
 }
 
-static int init_stat_file(struct tracer_stat_session *session)
+static int init_stat_file(struct stat_session *session)
 {
         if (!stat_dir && tracing_stat_init())
                 return -ENODEV;
@@ -266,7 +316,7 @@ static int init_stat_file(struct tracer_stat_session *session)
 
 int register_stat_tracer(struct tracer_stat *trace)
 {
-        struct tracer_stat_session *session, *node, *tmp;
+        struct stat_session *session, *node;
         int ret;
 
         if (!trace)
@@ -277,7 +327,7 @@ int register_stat_tracer(struct tracer_stat *trace)
 
         /* Already registered? */
         mutex_lock(&all_stat_sessions_mutex);
-        list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {
+        list_for_each_entry(node, &all_stat_sessions, session_list) {
                 if (node->ts == trace) {
                         mutex_unlock(&all_stat_sessions_mutex);
                         return -EINVAL;
@@ -286,15 +336,13 @@ int register_stat_tracer(struct tracer_stat *trace)
         mutex_unlock(&all_stat_sessions_mutex);
 
         /* Init the session */
-        session = kmalloc(sizeof(struct tracer_stat_session), GFP_KERNEL);
+        session = kzalloc(sizeof(*session), GFP_KERNEL);
         if (!session)
                 return -ENOMEM;
 
         session->ts = trace;
         INIT_LIST_HEAD(&session->session_list);
-        INIT_LIST_HEAD(&session->stat_list);
         mutex_init(&session->stat_mutex);
-        session->file = NULL;
 
         ret = init_stat_file(session);
         if (ret) {
@@ -312,7 +360,7 @@ int register_stat_tracer(struct tracer_stat *trace)
 
 void unregister_stat_tracer(struct tracer_stat *trace)
 {
-        struct tracer_stat_session *node, *tmp;
+        struct stat_session *node, *tmp;
 
         mutex_lock(&all_stat_sessions_mutex);
         list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) {