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-rw-r--r--kernel/trace/trace_stat.c326
1 files changed, 326 insertions, 0 deletions
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
new file mode 100644
index 000000000000..acdebd771a93
--- /dev/null
+++ b/kernel/trace/trace_stat.c
@@ -0,0 +1,326 @@
+/*
+ * Infrastructure for statistic tracing (histogram output).
+ *
+ * Copyright (C) 2008 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/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;
+};
+
+/* A stat session is the stats output in one file */
+struct tracer_stat_session {
+ struct list_head session_list;
+ struct tracer_stat *ts;
+ struct list_head stat_list;
+ struct mutex stat_mutex;
+ struct dentry *file;
+};
+
+/* 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;
+
+
+static void reset_stat_session(struct tracer_stat_session *session)
+{
+ struct trace_stat_list *node, *next;
+
+ list_for_each_entry_safe(node, next, &session->stat_list, list)
+ kfree(node);
+
+ INIT_LIST_HEAD(&session->stat_list);
+}
+
+static void destroy_session(struct tracer_stat_session *session)
+{
+ debugfs_remove(session->file);
+ reset_stat_session(session);
+ mutex_destroy(&session->stat_mutex);
+ kfree(session);
+}
+
+/*
+ * For tracers that don't provide a stat_cmp callback.
+ * This one will force an immediate insertion on tail of
+ * the list.
+ */
+static int dummy_cmp(void *p1, void *p2)
+{
+ return 1;
+}
+
+/*
+ * Initialize the stat list 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)
+{
+ struct trace_stat_list *iter_entry, *new_entry;
+ struct tracer_stat *ts = session->ts;
+ void *stat;
+ int ret = 0;
+ int i;
+
+ mutex_lock(&session->stat_mutex);
+ reset_stat_session(session);
+
+ if (!ts->stat_cmp)
+ ts->stat_cmp = dummy_cmp;
+
+ stat = ts->stat_start();
+ 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;
+ 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.
+ */
+ for (i = 1; ; i++) {
+ stat = ts->stat_next(stat, i);
+
+ /* End of insertion */
+ 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);
+ }
+exit:
+ mutex_unlock(&session->stat_mutex);
+ return ret;
+
+exit_free_list:
+ reset_stat_session(session);
+ mutex_unlock(&session->stat_mutex);
+ return ret;
+}
+
+
+static void *stat_seq_start(struct seq_file *s, loff_t *pos)
+{
+ struct tracer_stat_session *session = s->private;
+
+ /* Prevent from tracer switch or stat_list modification */
+ mutex_lock(&session->stat_mutex);
+
+ /* If we are in the beginning of the file, print the headers */
+ if (!*pos && session->ts->stat_headers)
+ return SEQ_START_TOKEN;
+
+ return seq_list_start(&session->stat_list, *pos);
+}
+
+static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos)
+{
+ struct tracer_stat_session *session = s->private;
+
+ if (p == SEQ_START_TOKEN)
+ return seq_list_start(&session->stat_list, *pos);
+
+ return seq_list_next(p, &session->stat_list, pos);
+}
+
+static void stat_seq_stop(struct seq_file *s, void *p)
+{
+ struct tracer_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);
+
+ 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
+};
+
+/* 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 tracer_stat_session *session = inode->i_private;
+
+ ret = seq_open(file, &trace_stat_seq_ops);
+ if (!ret) {
+ struct seq_file *m = file->private_data;
+ m->private = session;
+ ret = stat_seq_init(session);
+ }
+
+ return ret;
+}
+
+/*
+ * Avoid consuming memory with our now useless list.
+ */
+static int tracing_stat_release(struct inode *i, struct file *f)
+{
+ struct tracer_stat_session *session = i->i_private;
+
+ mutex_lock(&session->stat_mutex);
+ reset_stat_session(session);
+ mutex_unlock(&session->stat_mutex);
+
+ return 0;
+}
+
+static const struct file_operations tracing_stat_fops = {
+ .open = tracing_stat_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = tracing_stat_release
+};
+
+static int tracing_stat_init(void)
+{
+ struct dentry *d_tracing;
+
+ d_tracing = tracing_init_dentry();
+
+ stat_dir = debugfs_create_dir("trace_stat", d_tracing);
+ if (!stat_dir)
+ pr_warning("Could not create debugfs "
+ "'trace_stat' entry\n");
+ return 0;
+}
+
+static int init_stat_file(struct tracer_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 tracer_stat_session *session, *node, *tmp;
+ 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_safe(node, tmp, &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 = kmalloc(sizeof(struct tracer_stat_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) {
+ 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 tracer_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);
+}