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 | */ | |
d8ea37d5 LJ |
52 | static struct rb_node *release_next(struct tracer_stat *ts, |
53 | struct rb_node *node) | |
8f184f27 FW |
54 | { |
55 | struct stat_node *snode; | |
56 | struct rb_node *parent = rb_parent(node); | |
57 | ||
58 | if (node->rb_left) | |
59 | return node->rb_left; | |
60 | else if (node->rb_right) | |
61 | return node->rb_right; | |
62 | else { | |
63 | if (!parent) | |
e1622806 LZ |
64 | ; |
65 | else if (parent->rb_left == node) | |
8f184f27 FW |
66 | parent->rb_left = NULL; |
67 | else | |
68 | parent->rb_right = NULL; | |
69 | ||
70 | snode = container_of(node, struct stat_node, node); | |
d8ea37d5 LJ |
71 | if (ts->stat_release) |
72 | ts->stat_release(snode->stat); | |
8f184f27 FW |
73 | kfree(snode); |
74 | ||
75 | return parent; | |
76 | } | |
77 | } | |
dbd0b4b3 | 78 | |
636eacee | 79 | static void __reset_stat_session(struct stat_session *session) |
dbd0b4b3 | 80 | { |
8f184f27 | 81 | struct rb_node *node = session->stat_root.rb_node; |
dbd0b4b3 | 82 | |
8f184f27 | 83 | while (node) |
d8ea37d5 | 84 | node = release_next(session->ts, node); |
dbd0b4b3 | 85 | |
8f184f27 | 86 | session->stat_root = RB_ROOT; |
dbd0b4b3 FW |
87 | } |
88 | ||
636eacee LZ |
89 | static void reset_stat_session(struct stat_session *session) |
90 | { | |
91 | mutex_lock(&session->stat_mutex); | |
92 | __reset_stat_session(session); | |
93 | mutex_unlock(&session->stat_mutex); | |
94 | } | |
95 | ||
0d64f834 | 96 | static void destroy_session(struct stat_session *session) |
dbd0b4b3 | 97 | { |
002bb86d | 98 | debugfs_remove(session->file); |
636eacee | 99 | __reset_stat_session(session); |
002bb86d FW |
100 | mutex_destroy(&session->stat_mutex); |
101 | kfree(session); | |
102 | } | |
034939b6 | 103 | |
8f184f27 FW |
104 | typedef int (*cmp_stat_t)(void *, void *); |
105 | ||
dbd3fbdf | 106 | static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp) |
8f184f27 FW |
107 | { |
108 | struct rb_node **new = &(root->rb_node), *parent = NULL; | |
dbd3fbdf LZ |
109 | struct stat_node *data; |
110 | ||
111 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
112 | if (!data) | |
113 | return -ENOMEM; | |
114 | data->stat = stat; | |
8f184f27 FW |
115 | |
116 | /* | |
117 | * Figure out where to put new node | |
118 | * This is a descendent sorting | |
119 | */ | |
120 | while (*new) { | |
121 | struct stat_node *this; | |
122 | int result; | |
123 | ||
124 | this = container_of(*new, struct stat_node, node); | |
125 | result = cmp(data->stat, this->stat); | |
126 | ||
127 | parent = *new; | |
128 | if (result >= 0) | |
129 | new = &((*new)->rb_left); | |
130 | else | |
131 | new = &((*new)->rb_right); | |
132 | } | |
133 | ||
134 | rb_link_node(&data->node, parent, new); | |
135 | rb_insert_color(&data->node, root); | |
dbd3fbdf | 136 | return 0; |
8f184f27 FW |
137 | } |
138 | ||
dbd0b4b3 FW |
139 | /* |
140 | * For tracers that don't provide a stat_cmp callback. | |
dbd3fbdf LZ |
141 | * This one will force an insertion as right-most node |
142 | * in the rbtree. | |
dbd0b4b3 FW |
143 | */ |
144 | static int dummy_cmp(void *p1, void *p2) | |
145 | { | |
b3dd7ba7 | 146 | return -1; |
dbd0b4b3 FW |
147 | } |
148 | ||
149 | /* | |
dbd3fbdf | 150 | * Initialize the stat rbtree at each trace_stat file opening. |
dbd0b4b3 FW |
151 | * All of these copies and sorting are required on all opening |
152 | * since the stats could have changed between two file sessions. | |
153 | */ | |
0d64f834 | 154 | static int stat_seq_init(struct stat_session *session) |
dbd0b4b3 | 155 | { |
034939b6 | 156 | struct tracer_stat *ts = session->ts; |
dbd3fbdf | 157 | struct rb_root *root = &session->stat_root; |
09833521 | 158 | void *stat; |
dbd0b4b3 FW |
159 | int ret = 0; |
160 | int i; | |
161 | ||
034939b6 | 162 | mutex_lock(&session->stat_mutex); |
636eacee | 163 | __reset_stat_session(session); |
dbd0b4b3 | 164 | |
034939b6 FW |
165 | if (!ts->stat_cmp) |
166 | ts->stat_cmp = dummy_cmp; | |
dbd0b4b3 | 167 | |
42548008 | 168 | stat = ts->stat_start(ts); |
09833521 SR |
169 | if (!stat) |
170 | goto exit; | |
171 | ||
dbd3fbdf LZ |
172 | ret = insert_stat(root, stat, ts->stat_cmp); |
173 | if (ret) | |
dbd0b4b3 | 174 | goto exit; |
dbd0b4b3 FW |
175 | |
176 | /* | |
dbd3fbdf | 177 | * Iterate over the tracer stat entries and store them in an rbtree. |
dbd0b4b3 FW |
178 | */ |
179 | for (i = 1; ; i++) { | |
09833521 SR |
180 | stat = ts->stat_next(stat, i); |
181 | ||
182 | /* End of insertion */ | |
183 | if (!stat) | |
184 | break; | |
185 | ||
dbd3fbdf LZ |
186 | ret = insert_stat(root, stat, ts->stat_cmp); |
187 | if (ret) | |
188 | goto exit_free_rbtree; | |
dbd0b4b3 | 189 | } |
8f184f27 | 190 | |
dbd0b4b3 | 191 | exit: |
034939b6 | 192 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
193 | return ret; |
194 | ||
dbd3fbdf | 195 | exit_free_rbtree: |
636eacee | 196 | __reset_stat_session(session); |
034939b6 | 197 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
198 | return ret; |
199 | } | |
200 | ||
201 | ||
202 | static void *stat_seq_start(struct seq_file *s, loff_t *pos) | |
203 | { | |
0d64f834 | 204 | struct stat_session *session = s->private; |
8f184f27 FW |
205 | struct rb_node *node; |
206 | int i; | |
dbd0b4b3 | 207 | |
dbd3fbdf | 208 | /* Prevent from tracer switch or rbtree modification */ |
034939b6 | 209 | mutex_lock(&session->stat_mutex); |
dbd0b4b3 FW |
210 | |
211 | /* If we are in the beginning of the file, print the headers */ | |
2961bf34 | 212 | if (!*pos && session->ts->stat_headers) |
e6f48901 | 213 | return SEQ_START_TOKEN; |
dbd0b4b3 | 214 | |
8f184f27 FW |
215 | node = rb_first(&session->stat_root); |
216 | for (i = 0; node && i < *pos; i++) | |
217 | node = rb_next(node); | |
218 | ||
8f184f27 | 219 | return node; |
dbd0b4b3 FW |
220 | } |
221 | ||
222 | static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos) | |
223 | { | |
0d64f834 | 224 | struct stat_session *session = s->private; |
8f184f27 FW |
225 | struct rb_node *node = p; |
226 | ||
227 | (*pos)++; | |
dbd0b4b3 | 228 | |
e6f48901 | 229 | if (p == SEQ_START_TOKEN) |
8f184f27 | 230 | return rb_first(&session->stat_root); |
e6f48901 | 231 | |
8f184f27 | 232 | return rb_next(node); |
dbd0b4b3 FW |
233 | } |
234 | ||
034939b6 | 235 | static void stat_seq_stop(struct seq_file *s, void *p) |
dbd0b4b3 | 236 | { |
0d64f834 | 237 | struct stat_session *session = s->private; |
034939b6 | 238 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
239 | } |
240 | ||
241 | static int stat_seq_show(struct seq_file *s, void *v) | |
242 | { | |
0d64f834 | 243 | struct stat_session *session = s->private; |
8f184f27 | 244 | struct stat_node *l = container_of(v, struct stat_node, node); |
ff288b27 | 245 | |
e6f48901 LJ |
246 | if (v == SEQ_START_TOKEN) |
247 | return session->ts->stat_headers(s); | |
248 | ||
034939b6 | 249 | return session->ts->stat_show(s, l->stat); |
dbd0b4b3 FW |
250 | } |
251 | ||
252 | static const struct seq_operations trace_stat_seq_ops = { | |
55922173 IM |
253 | .start = stat_seq_start, |
254 | .next = stat_seq_next, | |
255 | .stop = stat_seq_stop, | |
256 | .show = stat_seq_show | |
dbd0b4b3 FW |
257 | }; |
258 | ||
034939b6 | 259 | /* The session stat is refilled and resorted at each stat file opening */ |
dbd0b4b3 FW |
260 | static int tracing_stat_open(struct inode *inode, struct file *file) |
261 | { | |
262 | int ret; | |
636eacee | 263 | struct seq_file *m; |
0d64f834 | 264 | struct stat_session *session = inode->i_private; |
034939b6 | 265 | |
636eacee LZ |
266 | ret = stat_seq_init(session); |
267 | if (ret) | |
268 | return ret; | |
269 | ||
dbd0b4b3 | 270 | ret = seq_open(file, &trace_stat_seq_ops); |
636eacee LZ |
271 | if (ret) { |
272 | reset_stat_session(session); | |
273 | return ret; | |
dbd0b4b3 FW |
274 | } |
275 | ||
636eacee LZ |
276 | m = file->private_data; |
277 | m->private = session; | |
dbd0b4b3 FW |
278 | return ret; |
279 | } | |
280 | ||
dbd0b4b3 | 281 | /* |
dbd3fbdf | 282 | * Avoid consuming memory with our now useless rbtree. |
dbd0b4b3 FW |
283 | */ |
284 | static int tracing_stat_release(struct inode *i, struct file *f) | |
285 | { | |
0d64f834 | 286 | struct stat_session *session = i->i_private; |
034939b6 | 287 | |
034939b6 | 288 | reset_stat_session(session); |
034939b6 | 289 | |
636eacee | 290 | return seq_release(i, f); |
dbd0b4b3 FW |
291 | } |
292 | ||
293 | static const struct file_operations tracing_stat_fops = { | |
294 | .open = tracing_stat_open, | |
295 | .read = seq_read, | |
296 | .llseek = seq_lseek, | |
297 | .release = tracing_stat_release | |
298 | }; | |
299 | ||
002bb86d | 300 | static int tracing_stat_init(void) |
dbd0b4b3 FW |
301 | { |
302 | struct dentry *d_tracing; | |
dbd0b4b3 | 303 | |
dbd0b4b3 FW |
304 | d_tracing = tracing_init_dentry(); |
305 | ||
034939b6 FW |
306 | stat_dir = debugfs_create_dir("trace_stat", d_tracing); |
307 | if (!stat_dir) | |
dbd0b4b3 FW |
308 | pr_warning("Could not create debugfs " |
309 | "'trace_stat' entry\n"); | |
310 | return 0; | |
311 | } | |
002bb86d | 312 | |
0d64f834 | 313 | static int init_stat_file(struct stat_session *session) |
002bb86d FW |
314 | { |
315 | if (!stat_dir && tracing_stat_init()) | |
316 | return -ENODEV; | |
317 | ||
318 | session->file = debugfs_create_file(session->ts->name, 0644, | |
319 | stat_dir, | |
320 | session, &tracing_stat_fops); | |
321 | if (!session->file) | |
322 | return -ENOMEM; | |
323 | return 0; | |
324 | } | |
55922173 IM |
325 | |
326 | int register_stat_tracer(struct tracer_stat *trace) | |
327 | { | |
43bd1236 | 328 | struct stat_session *session, *node; |
55922173 IM |
329 | int ret; |
330 | ||
331 | if (!trace) | |
332 | return -EINVAL; | |
333 | ||
334 | if (!trace->stat_start || !trace->stat_next || !trace->stat_show) | |
335 | return -EINVAL; | |
336 | ||
337 | /* Already registered? */ | |
338 | mutex_lock(&all_stat_sessions_mutex); | |
43bd1236 | 339 | list_for_each_entry(node, &all_stat_sessions, session_list) { |
55922173 IM |
340 | if (node->ts == trace) { |
341 | mutex_unlock(&all_stat_sessions_mutex); | |
342 | return -EINVAL; | |
343 | } | |
344 | } | |
345 | mutex_unlock(&all_stat_sessions_mutex); | |
346 | ||
347 | /* Init the session */ | |
8f184f27 | 348 | session = kzalloc(sizeof(*session), GFP_KERNEL); |
55922173 IM |
349 | if (!session) |
350 | return -ENOMEM; | |
351 | ||
352 | session->ts = trace; | |
353 | INIT_LIST_HEAD(&session->session_list); | |
55922173 | 354 | mutex_init(&session->stat_mutex); |
55922173 IM |
355 | |
356 | ret = init_stat_file(session); | |
357 | if (ret) { | |
358 | destroy_session(session); | |
359 | return ret; | |
360 | } | |
361 | ||
362 | /* Register */ | |
363 | mutex_lock(&all_stat_sessions_mutex); | |
364 | list_add_tail(&session->session_list, &all_stat_sessions); | |
365 | mutex_unlock(&all_stat_sessions_mutex); | |
366 | ||
367 | return 0; | |
368 | } | |
369 | ||
370 | void unregister_stat_tracer(struct tracer_stat *trace) | |
371 | { | |
0d64f834 | 372 | struct stat_session *node, *tmp; |
55922173 IM |
373 | |
374 | mutex_lock(&all_stat_sessions_mutex); | |
375 | list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) { | |
376 | if (node->ts == trace) { | |
377 | list_del(&node->session_list); | |
378 | destroy_session(node); | |
379 | break; | |
380 | } | |
381 | } | |
382 | mutex_unlock(&all_stat_sessions_mutex); | |
383 | } |