trace_stat.rar_trace

/* * Infrastructure for statistic tracing (histogram output). * * */ #include <linux/list.h> #include <linux/slab.h> #include <linux/rbtree.h> #include <linux/debugfs.h> #include "trace_stat.h" #include "trace.h" /* * 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 stat_session { struct list_head session_list; struct tracer_stat *ts; struct rb_root stat_root; 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; /* * 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 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_session(struct stat_session *session) { struct rb_node *node = session->stat_root.rb_node; while (node) node = release_next(session->ts, node); session->stat_root = RB_ROOT; } static void reset_stat_session(struct stat_session *session) { 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 insertion as right-most node * in the rbtree. */ static int dummy_cmp(void *p1, void *p2) { return -1; } /* * 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 stat_session *session) { struct tracer_stat *ts = session->ts; struct rb_root *root = &session->stat_root; 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(ts); if (!stat) goto exit; ret = insert_stat(root, stat, ts->stat_cmp); if (ret) goto exit; /* * Iterate over the tracer stat entries and store them in an rbtree. */ for (i = 1; ; i++) { stat = ts->stat_next(stat, i); /* End of insertion */ if (!stat) break; ret = insert_stat(root, stat, ts->stat_cmp); if (ret) goto exit_free_rbtree; } exit: mutex_unlock(&session->stat_mutex); return ret; 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 stat_session *session = s->private; struct rb_node *node; int n = *pos; int i; /* 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 (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 node; } static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos) { struct stat_session *session = s->private; struct rb_node *node = p; (*pos)++; if (p == SEQ_START_TOKEN) return rb_first(&session->stat_root); return rb_next(node); } static void stat_seq_stop(struct seq_file *s, void *p) { struct stat_session *session = s->private; mutex_unlock(&session->stat_mutex); } static int stat_seq_show(struct seq_file *s, void *v) { 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 }; /* 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) { reset_stat_session(session); return ret; } m = file->private_data; m->private = session; return ret; } /* * Avoid consuming memory with our now useless rbtree. */ static int tracing_stat_release(struct inode *i, struct file *f) { struct stat_session *session = i->i_private; reset_stat_session(session); return seq_release(i, f); } 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 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_fo