Commit | Line | Data |
---|---|---|
dbd0b4b3 FW |
1 | /* |
2 | * Infrastructure for statistic tracing (histogram output). | |
3 | * | |
8f184f27 | 4 | * Copyright (C) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com> |
dbd0b4b3 FW |
5 | * |
6 | * Based on the code from trace_branch.c which is | |
7 | * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com> | |
8 | * | |
9 | */ | |
10 | ||
11 | ||
12 | #include <linux/list.h> | |
8f184f27 | 13 | #include <linux/rbtree.h> |
dbd0b4b3 | 14 | #include <linux/debugfs.h> |
002bb86d | 15 | #include "trace_stat.h" |
dbd0b4b3 FW |
16 | #include "trace.h" |
17 | ||
18 | ||
8f184f27 FW |
19 | /* |
20 | * List of stat red-black nodes from a tracer | |
21 | * We use a such tree to sort quickly the stat | |
22 | * entries from the tracer. | |
23 | */ | |
24 | struct stat_node { | |
25 | struct rb_node node; | |
55922173 | 26 | void *stat; |
dbd0b4b3 FW |
27 | }; |
28 | ||
034939b6 | 29 | /* A stat session is the stats output in one file */ |
0d64f834 | 30 | struct stat_session { |
002bb86d | 31 | struct list_head session_list; |
55922173 | 32 | struct tracer_stat *ts; |
8f184f27 | 33 | struct rb_root stat_root; |
55922173 | 34 | struct mutex stat_mutex; |
002bb86d | 35 | struct dentry *file; |
034939b6 | 36 | }; |
dbd0b4b3 | 37 | |
73d8b8bc | 38 | /* All of the sessions currently in use. Each stat file embed one session */ |
002bb86d FW |
39 | static LIST_HEAD(all_stat_sessions); |
40 | static DEFINE_MUTEX(all_stat_sessions_mutex); | |
41 | ||
42 | /* The root directory for all stat files */ | |
55922173 | 43 | static struct dentry *stat_dir; |
dbd0b4b3 | 44 | |
8f184f27 FW |
45 | /* |
46 | * Iterate through the rbtree using a post order traversal path | |
47 | * to release the next node. | |
48 | * It won't necessary release one at each iteration | |
49 | * but it will at least advance closer to the next one | |
50 | * to be released. | |
51 | */ | |
52 | static struct rb_node *release_next(struct rb_node *node) | |
53 | { | |
54 | struct stat_node *snode; | |
55 | struct rb_node *parent = rb_parent(node); | |
56 | ||
57 | if (node->rb_left) | |
58 | return node->rb_left; | |
59 | else if (node->rb_right) | |
60 | return node->rb_right; | |
61 | else { | |
62 | if (!parent) | |
e1622806 LZ |
63 | ; |
64 | else if (parent->rb_left == node) | |
8f184f27 FW |
65 | parent->rb_left = NULL; |
66 | else | |
67 | parent->rb_right = NULL; | |
68 | ||
69 | snode = container_of(node, struct stat_node, node); | |
70 | kfree(snode); | |
71 | ||
72 | return parent; | |
73 | } | |
74 | } | |
dbd0b4b3 | 75 | |
0d64f834 | 76 | static void reset_stat_session(struct stat_session *session) |
dbd0b4b3 | 77 | { |
8f184f27 | 78 | struct rb_node *node = session->stat_root.rb_node; |
dbd0b4b3 | 79 | |
8f184f27 FW |
80 | while (node) |
81 | node = release_next(node); | |
dbd0b4b3 | 82 | |
8f184f27 | 83 | session->stat_root = RB_ROOT; |
dbd0b4b3 FW |
84 | } |
85 | ||
0d64f834 | 86 | static void destroy_session(struct stat_session *session) |
dbd0b4b3 | 87 | { |
002bb86d FW |
88 | debugfs_remove(session->file); |
89 | reset_stat_session(session); | |
90 | mutex_destroy(&session->stat_mutex); | |
91 | kfree(session); | |
92 | } | |
034939b6 | 93 | |
8f184f27 FW |
94 | typedef int (*cmp_stat_t)(void *, void *); |
95 | ||
dbd3fbdf | 96 | static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp) |
8f184f27 FW |
97 | { |
98 | struct rb_node **new = &(root->rb_node), *parent = NULL; | |
dbd3fbdf LZ |
99 | struct stat_node *data; |
100 | ||
101 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
102 | if (!data) | |
103 | return -ENOMEM; | |
104 | data->stat = stat; | |
8f184f27 FW |
105 | |
106 | /* | |
107 | * Figure out where to put new node | |
108 | * This is a descendent sorting | |
109 | */ | |
110 | while (*new) { | |
111 | struct stat_node *this; | |
112 | int result; | |
113 | ||
114 | this = container_of(*new, struct stat_node, node); | |
115 | result = cmp(data->stat, this->stat); | |
116 | ||
117 | parent = *new; | |
118 | if (result >= 0) | |
119 | new = &((*new)->rb_left); | |
120 | else | |
121 | new = &((*new)->rb_right); | |
122 | } | |
123 | ||
124 | rb_link_node(&data->node, parent, new); | |
125 | rb_insert_color(&data->node, root); | |
dbd3fbdf | 126 | return 0; |
8f184f27 FW |
127 | } |
128 | ||
dbd0b4b3 FW |
129 | /* |
130 | * For tracers that don't provide a stat_cmp callback. | |
dbd3fbdf LZ |
131 | * This one will force an insertion as right-most node |
132 | * in the rbtree. | |
dbd0b4b3 FW |
133 | */ |
134 | static int dummy_cmp(void *p1, void *p2) | |
135 | { | |
b3dd7ba7 | 136 | return -1; |
dbd0b4b3 FW |
137 | } |
138 | ||
139 | /* | |
dbd3fbdf | 140 | * Initialize the stat rbtree at each trace_stat file opening. |
dbd0b4b3 FW |
141 | * All of these copies and sorting are required on all opening |
142 | * since the stats could have changed between two file sessions. | |
143 | */ | |
0d64f834 | 144 | static int stat_seq_init(struct stat_session *session) |
dbd0b4b3 | 145 | { |
034939b6 | 146 | struct tracer_stat *ts = session->ts; |
dbd3fbdf | 147 | struct rb_root *root = &session->stat_root; |
09833521 | 148 | void *stat; |
dbd0b4b3 FW |
149 | int ret = 0; |
150 | int i; | |
151 | ||
034939b6 FW |
152 | mutex_lock(&session->stat_mutex); |
153 | reset_stat_session(session); | |
dbd0b4b3 | 154 | |
034939b6 FW |
155 | if (!ts->stat_cmp) |
156 | ts->stat_cmp = dummy_cmp; | |
dbd0b4b3 | 157 | |
42548008 | 158 | stat = ts->stat_start(ts); |
09833521 SR |
159 | if (!stat) |
160 | goto exit; | |
161 | ||
dbd3fbdf LZ |
162 | ret = insert_stat(root, stat, ts->stat_cmp); |
163 | if (ret) | |
dbd0b4b3 | 164 | goto exit; |
dbd0b4b3 FW |
165 | |
166 | /* | |
dbd3fbdf | 167 | * Iterate over the tracer stat entries and store them in an rbtree. |
dbd0b4b3 FW |
168 | */ |
169 | for (i = 1; ; i++) { | |
09833521 SR |
170 | stat = ts->stat_next(stat, i); |
171 | ||
172 | /* End of insertion */ | |
173 | if (!stat) | |
174 | break; | |
175 | ||
dbd3fbdf LZ |
176 | ret = insert_stat(root, stat, ts->stat_cmp); |
177 | if (ret) | |
178 | goto exit_free_rbtree; | |
dbd0b4b3 | 179 | } |
8f184f27 | 180 | |
dbd0b4b3 | 181 | exit: |
034939b6 | 182 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
183 | return ret; |
184 | ||
dbd3fbdf | 185 | exit_free_rbtree: |
034939b6 FW |
186 | reset_stat_session(session); |
187 | mutex_unlock(&session->stat_mutex); | |
dbd0b4b3 FW |
188 | return ret; |
189 | } | |
190 | ||
191 | ||
192 | static void *stat_seq_start(struct seq_file *s, loff_t *pos) | |
193 | { | |
0d64f834 | 194 | struct stat_session *session = s->private; |
8f184f27 FW |
195 | struct rb_node *node; |
196 | int i; | |
dbd0b4b3 | 197 | |
dbd3fbdf | 198 | /* Prevent from tracer switch or rbtree modification */ |
034939b6 | 199 | mutex_lock(&session->stat_mutex); |
dbd0b4b3 FW |
200 | |
201 | /* If we are in the beginning of the file, print the headers */ | |
8f184f27 FW |
202 | if (!*pos && session->ts->stat_headers) { |
203 | (*pos)++; | |
e6f48901 | 204 | return SEQ_START_TOKEN; |
8f184f27 | 205 | } |
dbd0b4b3 | 206 | |
8f184f27 FW |
207 | node = rb_first(&session->stat_root); |
208 | for (i = 0; node && i < *pos; i++) | |
209 | node = rb_next(node); | |
210 | ||
211 | (*pos)++; | |
212 | ||
213 | return node; | |
dbd0b4b3 FW |
214 | } |
215 | ||
216 | static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos) | |
217 | { | |
0d64f834 | 218 | struct stat_session *session = s->private; |
8f184f27 FW |
219 | struct rb_node *node = p; |
220 | ||
221 | (*pos)++; | |
dbd0b4b3 | 222 | |
e6f48901 | 223 | if (p == SEQ_START_TOKEN) |
8f184f27 | 224 | return rb_first(&session->stat_root); |
e6f48901 | 225 | |
8f184f27 | 226 | return rb_next(node); |
dbd0b4b3 FW |
227 | } |
228 | ||
034939b6 | 229 | static void stat_seq_stop(struct seq_file *s, void *p) |
dbd0b4b3 | 230 | { |
0d64f834 | 231 | struct stat_session *session = s->private; |
034939b6 | 232 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
233 | } |
234 | ||
235 | static int stat_seq_show(struct seq_file *s, void *v) | |
236 | { | |
0d64f834 | 237 | struct stat_session *session = s->private; |
8f184f27 | 238 | struct stat_node *l = container_of(v, struct stat_node, node); |
ff288b27 | 239 | |
e6f48901 LJ |
240 | if (v == SEQ_START_TOKEN) |
241 | return session->ts->stat_headers(s); | |
242 | ||
034939b6 | 243 | return session->ts->stat_show(s, l->stat); |
dbd0b4b3 FW |
244 | } |
245 | ||
246 | static const struct seq_operations trace_stat_seq_ops = { | |
55922173 IM |
247 | .start = stat_seq_start, |
248 | .next = stat_seq_next, | |
249 | .stop = stat_seq_stop, | |
250 | .show = stat_seq_show | |
dbd0b4b3 FW |
251 | }; |
252 | ||
034939b6 | 253 | /* The session stat is refilled and resorted at each stat file opening */ |
dbd0b4b3 FW |
254 | static int tracing_stat_open(struct inode *inode, struct file *file) |
255 | { | |
256 | int ret; | |
257 | ||
0d64f834 | 258 | struct stat_session *session = inode->i_private; |
034939b6 | 259 | |
dbd0b4b3 FW |
260 | ret = seq_open(file, &trace_stat_seq_ops); |
261 | if (!ret) { | |
262 | struct seq_file *m = file->private_data; | |
034939b6 FW |
263 | m->private = session; |
264 | ret = stat_seq_init(session); | |
dbd0b4b3 FW |
265 | } |
266 | ||
267 | return ret; | |
268 | } | |
269 | ||
dbd0b4b3 | 270 | /* |
dbd3fbdf | 271 | * Avoid consuming memory with our now useless rbtree. |
dbd0b4b3 FW |
272 | */ |
273 | static int tracing_stat_release(struct inode *i, struct file *f) | |
274 | { | |
0d64f834 | 275 | struct stat_session *session = i->i_private; |
034939b6 FW |
276 | |
277 | mutex_lock(&session->stat_mutex); | |
278 | reset_stat_session(session); | |
279 | mutex_unlock(&session->stat_mutex); | |
280 | ||
dbd0b4b3 FW |
281 | return 0; |
282 | } | |
283 | ||
284 | static const struct file_operations tracing_stat_fops = { | |
285 | .open = tracing_stat_open, | |
286 | .read = seq_read, | |
287 | .llseek = seq_lseek, | |
288 | .release = tracing_stat_release | |
289 | }; | |
290 | ||
002bb86d | 291 | static int tracing_stat_init(void) |
dbd0b4b3 FW |
292 | { |
293 | struct dentry *d_tracing; | |
dbd0b4b3 | 294 | |
dbd0b4b3 FW |
295 | d_tracing = tracing_init_dentry(); |
296 | ||
034939b6 FW |
297 | stat_dir = debugfs_create_dir("trace_stat", d_tracing); |
298 | if (!stat_dir) | |
dbd0b4b3 FW |
299 | pr_warning("Could not create debugfs " |
300 | "'trace_stat' entry\n"); | |
301 | return 0; | |
302 | } | |
002bb86d | 303 | |
0d64f834 | 304 | static int init_stat_file(struct stat_session *session) |
002bb86d FW |
305 | { |
306 | if (!stat_dir && tracing_stat_init()) | |
307 | return -ENODEV; | |
308 | ||
309 | session->file = debugfs_create_file(session->ts->name, 0644, | |
310 | stat_dir, | |
311 | session, &tracing_stat_fops); | |
312 | if (!session->file) | |
313 | return -ENOMEM; | |
314 | return 0; | |
315 | } | |
55922173 IM |
316 | |
317 | int register_stat_tracer(struct tracer_stat *trace) | |
318 | { | |
0d64f834 | 319 | struct stat_session *session, *node, *tmp; |
55922173 IM |
320 | int ret; |
321 | ||
322 | if (!trace) | |
323 | return -EINVAL; | |
324 | ||
325 | if (!trace->stat_start || !trace->stat_next || !trace->stat_show) | |
326 | return -EINVAL; | |
327 | ||
328 | /* Already registered? */ | |
329 | mutex_lock(&all_stat_sessions_mutex); | |
330 | list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) { | |
331 | if (node->ts == trace) { | |
332 | mutex_unlock(&all_stat_sessions_mutex); | |
333 | return -EINVAL; | |
334 | } | |
335 | } | |
336 | mutex_unlock(&all_stat_sessions_mutex); | |
337 | ||
338 | /* Init the session */ | |
8f184f27 | 339 | session = kzalloc(sizeof(*session), GFP_KERNEL); |
55922173 IM |
340 | if (!session) |
341 | return -ENOMEM; | |
342 | ||
343 | session->ts = trace; | |
344 | INIT_LIST_HEAD(&session->session_list); | |
55922173 | 345 | mutex_init(&session->stat_mutex); |
55922173 IM |
346 | |
347 | ret = init_stat_file(session); | |
348 | if (ret) { | |
349 | destroy_session(session); | |
350 | return ret; | |
351 | } | |
352 | ||
353 | /* Register */ | |
354 | mutex_lock(&all_stat_sessions_mutex); | |
355 | list_add_tail(&session->session_list, &all_stat_sessions); | |
356 | mutex_unlock(&all_stat_sessions_mutex); | |
357 | ||
358 | return 0; | |
359 | } | |
360 | ||
361 | void unregister_stat_tracer(struct tracer_stat *trace) | |
362 | { | |
0d64f834 | 363 | struct stat_session *node, *tmp; |
55922173 IM |
364 | |
365 | mutex_lock(&all_stat_sessions_mutex); | |
366 | list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) { | |
367 | if (node->ts == trace) { | |
368 | list_del(&node->session_list); | |
369 | destroy_session(node); | |
370 | break; | |
371 | } | |
372 | } | |
373 | mutex_unlock(&all_stat_sessions_mutex); | |
374 | } |