/*
* 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>
#include <linux/list.h>
-#include <linux/seq_file.h>
+#include <linux/slab.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 LIST_HEAD(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, *next;
+ struct rb_node *node = session->stat_root.rb_node;
- list_for_each_entry_safe(node, next, &stat_list, list)
- kfree(node);
+ while (node)
+ node = release_next(session->ts, node);
- INIT_LIST_HEAD(&stat_list);
+ session->stat_root = RB_ROOT;
}
-void init_tracer_stat(struct tracer *trace)
+static void reset_stat_session(struct stat_session *session)
{
- mutex_lock(&stat_list_mutex);
- current_tracer = *trace;
- mutex_unlock(&stat_list_mutex);
+ mutex_lock(&session->stat_mutex);
+ __reset_stat_session(session);
+ mutex_unlock(&session->stat_mutex);
+}
+
+static void destroy_session(struct stat_session *session)
+{
+ debugfs_remove(session->file);
+ __reset_stat_session(session);
+ mutex_destroy(&session->stat_mutex);
+ 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(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();
+ mutex_lock(&session->stat_mutex);
+ __reset_stat_session(session);
- if (!current_tracer.stat_start || !current_tracer.stat_next ||
- !current_tracer.stat_show)
- goto exit;
+ if (!ts->stat_cmp)
+ ts->stat_cmp = dummy_cmp;
- if (!current_tracer.stat_cmp)
- current_tracer.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);
- 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) {
- /* 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_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 list_head *l = (struct list_head *)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, *pos);
+ return node;
}
static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos)
{
- struct list_head *l = (struct list_head *)s->private;
+ struct stat_session *session = s->private;
+ struct rb_node *node = p;
+
+ (*pos)++;
+
+ if (p == SEQ_START_TOKEN)
+ return rb_first(&session->stat_root);
- return seq_list_next(p, l, pos);
+ 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 *entry =
- 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);
- return current_tracer.stat_show(s, entry->stat);
+ 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 = {
.release = tracing_stat_release
};
-static int __init tracing_stat_init(void)
+static int tracing_stat_init(void)
{
struct dentry *d_tracing;
- struct dentry *entry;
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);
+}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff