Commit | Line | Data |
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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 | ||
96 | static void | |
97 | insert_stat(struct rb_root *root, struct stat_node *data, cmp_stat_t cmp) | |
98 | { | |
99 | struct rb_node **new = &(root->rb_node), *parent = NULL; | |
100 | ||
101 | /* | |
102 | * Figure out where to put new node | |
103 | * This is a descendent sorting | |
104 | */ | |
105 | while (*new) { | |
106 | struct stat_node *this; | |
107 | int result; | |
108 | ||
109 | this = container_of(*new, struct stat_node, node); | |
110 | result = cmp(data->stat, this->stat); | |
111 | ||
112 | parent = *new; | |
113 | if (result >= 0) | |
114 | new = &((*new)->rb_left); | |
115 | else | |
116 | new = &((*new)->rb_right); | |
117 | } | |
118 | ||
119 | rb_link_node(&data->node, parent, new); | |
120 | rb_insert_color(&data->node, root); | |
121 | } | |
122 | ||
dbd0b4b3 FW |
123 | /* |
124 | * For tracers that don't provide a stat_cmp callback. | |
125 | * This one will force an immediate insertion on tail of | |
126 | * the list. | |
127 | */ | |
128 | static int dummy_cmp(void *p1, void *p2) | |
129 | { | |
b3dd7ba7 | 130 | return -1; |
dbd0b4b3 FW |
131 | } |
132 | ||
133 | /* | |
134 | * Initialize the stat list at each trace_stat file opening. | |
135 | * All of these copies and sorting are required on all opening | |
136 | * since the stats could have changed between two file sessions. | |
137 | */ | |
0d64f834 | 138 | static int stat_seq_init(struct stat_session *session) |
dbd0b4b3 | 139 | { |
034939b6 | 140 | struct tracer_stat *ts = session->ts; |
8f184f27 FW |
141 | struct stat_node *new_entry; |
142 | struct rb_root *root; | |
09833521 | 143 | void *stat; |
dbd0b4b3 FW |
144 | int ret = 0; |
145 | int i; | |
146 | ||
034939b6 FW |
147 | mutex_lock(&session->stat_mutex); |
148 | reset_stat_session(session); | |
dbd0b4b3 | 149 | |
034939b6 FW |
150 | if (!ts->stat_cmp) |
151 | ts->stat_cmp = dummy_cmp; | |
dbd0b4b3 | 152 | |
42548008 | 153 | stat = ts->stat_start(ts); |
09833521 SR |
154 | if (!stat) |
155 | goto exit; | |
156 | ||
dbd0b4b3 FW |
157 | /* |
158 | * The first entry. Actually this is the second, but the first | |
159 | * one (the stat_list head) is pointless. | |
160 | */ | |
8f184f27 | 161 | new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL); |
dbd0b4b3 FW |
162 | if (!new_entry) { |
163 | ret = -ENOMEM; | |
164 | goto exit; | |
165 | } | |
8f184f27 FW |
166 | root = &session->stat_root; |
167 | insert_stat(root, new_entry, dummy_cmp); | |
034939b6 | 168 | |
09833521 | 169 | new_entry->stat = stat; |
dbd0b4b3 FW |
170 | |
171 | /* | |
172 | * Iterate over the tracer stat entries and store them in a sorted | |
173 | * list. | |
174 | */ | |
175 | for (i = 1; ; i++) { | |
09833521 SR |
176 | stat = ts->stat_next(stat, i); |
177 | ||
178 | /* End of insertion */ | |
179 | if (!stat) | |
180 | break; | |
181 | ||
8f184f27 | 182 | new_entry = kzalloc(sizeof(*new_entry), GFP_KERNEL); |
dbd0b4b3 FW |
183 | if (!new_entry) { |
184 | ret = -ENOMEM; | |
185 | goto exit_free_list; | |
186 | } | |
187 | ||
09833521 | 188 | new_entry->stat = stat; |
dbd0b4b3 | 189 | |
8f184f27 | 190 | insert_stat(root, new_entry, ts->stat_cmp); |
dbd0b4b3 | 191 | } |
8f184f27 | 192 | |
dbd0b4b3 | 193 | exit: |
034939b6 | 194 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
195 | return ret; |
196 | ||
197 | exit_free_list: | |
034939b6 FW |
198 | reset_stat_session(session); |
199 | mutex_unlock(&session->stat_mutex); | |
dbd0b4b3 FW |
200 | return ret; |
201 | } | |
202 | ||
203 | ||
204 | static void *stat_seq_start(struct seq_file *s, loff_t *pos) | |
205 | { | |
0d64f834 | 206 | struct stat_session *session = s->private; |
8f184f27 FW |
207 | struct rb_node *node; |
208 | int i; | |
dbd0b4b3 FW |
209 | |
210 | /* Prevent from tracer switch or stat_list modification */ | |
034939b6 | 211 | mutex_lock(&session->stat_mutex); |
dbd0b4b3 FW |
212 | |
213 | /* If we are in the beginning of the file, print the headers */ | |
8f184f27 FW |
214 | if (!*pos && session->ts->stat_headers) { |
215 | (*pos)++; | |
e6f48901 | 216 | return SEQ_START_TOKEN; |
8f184f27 | 217 | } |
dbd0b4b3 | 218 | |
8f184f27 FW |
219 | node = rb_first(&session->stat_root); |
220 | for (i = 0; node && i < *pos; i++) | |
221 | node = rb_next(node); | |
222 | ||
223 | (*pos)++; | |
224 | ||
225 | return node; | |
dbd0b4b3 FW |
226 | } |
227 | ||
228 | static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos) | |
229 | { | |
0d64f834 | 230 | struct stat_session *session = s->private; |
8f184f27 FW |
231 | struct rb_node *node = p; |
232 | ||
233 | (*pos)++; | |
dbd0b4b3 | 234 | |
e6f48901 | 235 | if (p == SEQ_START_TOKEN) |
8f184f27 | 236 | return rb_first(&session->stat_root); |
e6f48901 | 237 | |
8f184f27 | 238 | return rb_next(node); |
dbd0b4b3 FW |
239 | } |
240 | ||
034939b6 | 241 | static void stat_seq_stop(struct seq_file *s, void *p) |
dbd0b4b3 | 242 | { |
0d64f834 | 243 | struct stat_session *session = s->private; |
034939b6 | 244 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
245 | } |
246 | ||
247 | static int stat_seq_show(struct seq_file *s, void *v) | |
248 | { | |
0d64f834 | 249 | struct stat_session *session = s->private; |
8f184f27 | 250 | struct stat_node *l = container_of(v, struct stat_node, node); |
ff288b27 | 251 | |
e6f48901 LJ |
252 | if (v == SEQ_START_TOKEN) |
253 | return session->ts->stat_headers(s); | |
254 | ||
034939b6 | 255 | return session->ts->stat_show(s, l->stat); |
dbd0b4b3 FW |
256 | } |
257 | ||
258 | static const struct seq_operations trace_stat_seq_ops = { | |
55922173 IM |
259 | .start = stat_seq_start, |
260 | .next = stat_seq_next, | |
261 | .stop = stat_seq_stop, | |
262 | .show = stat_seq_show | |
dbd0b4b3 FW |
263 | }; |
264 | ||
034939b6 | 265 | /* The session stat is refilled and resorted at each stat file opening */ |
dbd0b4b3 FW |
266 | static int tracing_stat_open(struct inode *inode, struct file *file) |
267 | { | |
268 | int ret; | |
269 | ||
0d64f834 | 270 | struct stat_session *session = inode->i_private; |
034939b6 | 271 | |
dbd0b4b3 FW |
272 | ret = seq_open(file, &trace_stat_seq_ops); |
273 | if (!ret) { | |
274 | struct seq_file *m = file->private_data; | |
034939b6 FW |
275 | m->private = session; |
276 | ret = stat_seq_init(session); | |
dbd0b4b3 FW |
277 | } |
278 | ||
279 | return ret; | |
280 | } | |
281 | ||
dbd0b4b3 FW |
282 | /* |
283 | * Avoid consuming memory with our now useless list. | |
284 | */ | |
285 | static int tracing_stat_release(struct inode *i, struct file *f) | |
286 | { | |
0d64f834 | 287 | struct stat_session *session = i->i_private; |
034939b6 FW |
288 | |
289 | mutex_lock(&session->stat_mutex); | |
290 | reset_stat_session(session); | |
291 | mutex_unlock(&session->stat_mutex); | |
292 | ||
dbd0b4b3 FW |
293 | return 0; |
294 | } | |
295 | ||
296 | static const struct file_operations tracing_stat_fops = { | |
297 | .open = tracing_stat_open, | |
298 | .read = seq_read, | |
299 | .llseek = seq_lseek, | |
300 | .release = tracing_stat_release | |
301 | }; | |
302 | ||
002bb86d | 303 | static int tracing_stat_init(void) |
dbd0b4b3 FW |
304 | { |
305 | struct dentry *d_tracing; | |
dbd0b4b3 | 306 | |
dbd0b4b3 FW |
307 | d_tracing = tracing_init_dentry(); |
308 | ||
034939b6 FW |
309 | stat_dir = debugfs_create_dir("trace_stat", d_tracing); |
310 | if (!stat_dir) | |
dbd0b4b3 FW |
311 | pr_warning("Could not create debugfs " |
312 | "'trace_stat' entry\n"); | |
313 | return 0; | |
314 | } | |
002bb86d | 315 | |
0d64f834 | 316 | static int init_stat_file(struct stat_session *session) |
002bb86d FW |
317 | { |
318 | if (!stat_dir && tracing_stat_init()) | |
319 | return -ENODEV; | |
320 | ||
321 | session->file = debugfs_create_file(session->ts->name, 0644, | |
322 | stat_dir, | |
323 | session, &tracing_stat_fops); | |
324 | if (!session->file) | |
325 | return -ENOMEM; | |
326 | return 0; | |
327 | } | |
55922173 IM |
328 | |
329 | int register_stat_tracer(struct tracer_stat *trace) | |
330 | { | |
0d64f834 | 331 | struct stat_session *session, *node, *tmp; |
55922173 IM |
332 | int ret; |
333 | ||
334 | if (!trace) | |
335 | return -EINVAL; | |
336 | ||
337 | if (!trace->stat_start || !trace->stat_next || !trace->stat_show) | |
338 | return -EINVAL; | |
339 | ||
340 | /* Already registered? */ | |
341 | mutex_lock(&all_stat_sessions_mutex); | |
342 | list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) { | |
343 | if (node->ts == trace) { | |
344 | mutex_unlock(&all_stat_sessions_mutex); | |
345 | return -EINVAL; | |
346 | } | |
347 | } | |
348 | mutex_unlock(&all_stat_sessions_mutex); | |
349 | ||
350 | /* Init the session */ | |
8f184f27 | 351 | session = kzalloc(sizeof(*session), GFP_KERNEL); |
55922173 IM |
352 | if (!session) |
353 | return -ENOMEM; | |
354 | ||
355 | session->ts = trace; | |
356 | INIT_LIST_HEAD(&session->session_list); | |
55922173 | 357 | mutex_init(&session->stat_mutex); |
55922173 IM |
358 | |
359 | ret = init_stat_file(session); | |
360 | if (ret) { | |
361 | destroy_session(session); | |
362 | return ret; | |
363 | } | |
364 | ||
365 | /* Register */ | |
366 | mutex_lock(&all_stat_sessions_mutex); | |
367 | list_add_tail(&session->session_list, &all_stat_sessions); | |
368 | mutex_unlock(&all_stat_sessions_mutex); | |
369 | ||
370 | return 0; | |
371 | } | |
372 | ||
373 | void unregister_stat_tracer(struct tracer_stat *trace) | |
374 | { | |
0d64f834 | 375 | struct stat_session *node, *tmp; |
55922173 IM |
376 | |
377 | mutex_lock(&all_stat_sessions_mutex); | |
378 | list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) { | |
379 | if (node->ts == trace) { | |
380 | list_del(&node->session_list); | |
381 | destroy_session(node); | |
382 | break; | |
383 | } | |
384 | } | |
385 | mutex_unlock(&all_stat_sessions_mutex); | |
386 | } |