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> | |
5a0e3ad6 | 13 | #include <linux/slab.h> |
8f184f27 | 14 | #include <linux/rbtree.h> |
dbd0b4b3 | 15 | #include <linux/debugfs.h> |
002bb86d | 16 | #include "trace_stat.h" |
dbd0b4b3 FW |
17 | #include "trace.h" |
18 | ||
19 | ||
8f184f27 FW |
20 | /* |
21 | * List of stat red-black nodes from a tracer | |
22 | * We use a such tree to sort quickly the stat | |
23 | * entries from the tracer. | |
24 | */ | |
25 | struct stat_node { | |
26 | struct rb_node node; | |
55922173 | 27 | void *stat; |
dbd0b4b3 FW |
28 | }; |
29 | ||
034939b6 | 30 | /* A stat session is the stats output in one file */ |
0d64f834 | 31 | struct stat_session { |
002bb86d | 32 | struct list_head session_list; |
55922173 | 33 | struct tracer_stat *ts; |
8f184f27 | 34 | struct rb_root stat_root; |
55922173 | 35 | struct mutex stat_mutex; |
002bb86d | 36 | struct dentry *file; |
034939b6 | 37 | }; |
dbd0b4b3 | 38 | |
73d8b8bc | 39 | /* All of the sessions currently in use. Each stat file embed one session */ |
002bb86d FW |
40 | static LIST_HEAD(all_stat_sessions); |
41 | static DEFINE_MUTEX(all_stat_sessions_mutex); | |
42 | ||
43 | /* The root directory for all stat files */ | |
55922173 | 44 | static struct dentry *stat_dir; |
dbd0b4b3 | 45 | |
9cd804ac | 46 | static void __reset_stat_session(struct stat_session *session) |
8f184f27 | 47 | { |
9cd804ac | 48 | struct stat_node *snode, *n; |
8f184f27 | 49 | |
9cd804ac CS |
50 | rbtree_postorder_for_each_entry_safe(snode, n, &session->stat_root, node) { |
51 | if (session->ts->stat_release) | |
52 | session->ts->stat_release(snode->stat); | |
8f184f27 | 53 | kfree(snode); |
8f184f27 | 54 | } |
dbd0b4b3 | 55 | |
8f184f27 | 56 | session->stat_root = RB_ROOT; |
dbd0b4b3 FW |
57 | } |
58 | ||
636eacee LZ |
59 | static void reset_stat_session(struct stat_session *session) |
60 | { | |
61 | mutex_lock(&session->stat_mutex); | |
62 | __reset_stat_session(session); | |
63 | mutex_unlock(&session->stat_mutex); | |
64 | } | |
65 | ||
0d64f834 | 66 | static void destroy_session(struct stat_session *session) |
dbd0b4b3 | 67 | { |
002bb86d | 68 | debugfs_remove(session->file); |
636eacee | 69 | __reset_stat_session(session); |
002bb86d FW |
70 | mutex_destroy(&session->stat_mutex); |
71 | kfree(session); | |
72 | } | |
034939b6 | 73 | |
8f184f27 FW |
74 | typedef int (*cmp_stat_t)(void *, void *); |
75 | ||
dbd3fbdf | 76 | static int insert_stat(struct rb_root *root, void *stat, cmp_stat_t cmp) |
8f184f27 FW |
77 | { |
78 | struct rb_node **new = &(root->rb_node), *parent = NULL; | |
dbd3fbdf LZ |
79 | struct stat_node *data; |
80 | ||
81 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
82 | if (!data) | |
83 | return -ENOMEM; | |
84 | data->stat = stat; | |
8f184f27 FW |
85 | |
86 | /* | |
87 | * Figure out where to put new node | |
88 | * This is a descendent sorting | |
89 | */ | |
90 | while (*new) { | |
91 | struct stat_node *this; | |
92 | int result; | |
93 | ||
94 | this = container_of(*new, struct stat_node, node); | |
95 | result = cmp(data->stat, this->stat); | |
96 | ||
97 | parent = *new; | |
98 | if (result >= 0) | |
99 | new = &((*new)->rb_left); | |
100 | else | |
101 | new = &((*new)->rb_right); | |
102 | } | |
103 | ||
104 | rb_link_node(&data->node, parent, new); | |
105 | rb_insert_color(&data->node, root); | |
dbd3fbdf | 106 | return 0; |
8f184f27 FW |
107 | } |
108 | ||
dbd0b4b3 FW |
109 | /* |
110 | * For tracers that don't provide a stat_cmp callback. | |
dbd3fbdf LZ |
111 | * This one will force an insertion as right-most node |
112 | * in the rbtree. | |
dbd0b4b3 FW |
113 | */ |
114 | static int dummy_cmp(void *p1, void *p2) | |
115 | { | |
b3dd7ba7 | 116 | return -1; |
dbd0b4b3 FW |
117 | } |
118 | ||
119 | /* | |
dbd3fbdf | 120 | * Initialize the stat rbtree at each trace_stat file opening. |
dbd0b4b3 FW |
121 | * All of these copies and sorting are required on all opening |
122 | * since the stats could have changed between two file sessions. | |
123 | */ | |
0d64f834 | 124 | static int stat_seq_init(struct stat_session *session) |
dbd0b4b3 | 125 | { |
034939b6 | 126 | struct tracer_stat *ts = session->ts; |
dbd3fbdf | 127 | struct rb_root *root = &session->stat_root; |
09833521 | 128 | void *stat; |
dbd0b4b3 FW |
129 | int ret = 0; |
130 | int i; | |
131 | ||
034939b6 | 132 | mutex_lock(&session->stat_mutex); |
636eacee | 133 | __reset_stat_session(session); |
dbd0b4b3 | 134 | |
034939b6 FW |
135 | if (!ts->stat_cmp) |
136 | ts->stat_cmp = dummy_cmp; | |
dbd0b4b3 | 137 | |
42548008 | 138 | stat = ts->stat_start(ts); |
09833521 SR |
139 | if (!stat) |
140 | goto exit; | |
141 | ||
dbd3fbdf LZ |
142 | ret = insert_stat(root, stat, ts->stat_cmp); |
143 | if (ret) | |
dbd0b4b3 | 144 | goto exit; |
dbd0b4b3 FW |
145 | |
146 | /* | |
dbd3fbdf | 147 | * Iterate over the tracer stat entries and store them in an rbtree. |
dbd0b4b3 FW |
148 | */ |
149 | for (i = 1; ; i++) { | |
09833521 SR |
150 | stat = ts->stat_next(stat, i); |
151 | ||
152 | /* End of insertion */ | |
153 | if (!stat) | |
154 | break; | |
155 | ||
dbd3fbdf LZ |
156 | ret = insert_stat(root, stat, ts->stat_cmp); |
157 | if (ret) | |
158 | goto exit_free_rbtree; | |
dbd0b4b3 | 159 | } |
8f184f27 | 160 | |
dbd0b4b3 | 161 | exit: |
034939b6 | 162 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
163 | return ret; |
164 | ||
dbd3fbdf | 165 | exit_free_rbtree: |
636eacee | 166 | __reset_stat_session(session); |
034939b6 | 167 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
168 | return ret; |
169 | } | |
170 | ||
171 | ||
172 | static void *stat_seq_start(struct seq_file *s, loff_t *pos) | |
173 | { | |
0d64f834 | 174 | struct stat_session *session = s->private; |
8f184f27 | 175 | struct rb_node *node; |
97d53202 | 176 | int n = *pos; |
8f184f27 | 177 | int i; |
dbd0b4b3 | 178 | |
dbd3fbdf | 179 | /* Prevent from tracer switch or rbtree modification */ |
034939b6 | 180 | mutex_lock(&session->stat_mutex); |
dbd0b4b3 FW |
181 | |
182 | /* If we are in the beginning of the file, print the headers */ | |
97d53202 LZ |
183 | if (session->ts->stat_headers) { |
184 | if (n == 0) | |
185 | return SEQ_START_TOKEN; | |
186 | n--; | |
187 | } | |
dbd0b4b3 | 188 | |
8f184f27 | 189 | node = rb_first(&session->stat_root); |
97d53202 | 190 | for (i = 0; node && i < n; i++) |
8f184f27 FW |
191 | node = rb_next(node); |
192 | ||
8f184f27 | 193 | return node; |
dbd0b4b3 FW |
194 | } |
195 | ||
196 | static void *stat_seq_next(struct seq_file *s, void *p, loff_t *pos) | |
197 | { | |
0d64f834 | 198 | struct stat_session *session = s->private; |
8f184f27 FW |
199 | struct rb_node *node = p; |
200 | ||
201 | (*pos)++; | |
dbd0b4b3 | 202 | |
e6f48901 | 203 | if (p == SEQ_START_TOKEN) |
8f184f27 | 204 | return rb_first(&session->stat_root); |
e6f48901 | 205 | |
8f184f27 | 206 | return rb_next(node); |
dbd0b4b3 FW |
207 | } |
208 | ||
034939b6 | 209 | static void stat_seq_stop(struct seq_file *s, void *p) |
dbd0b4b3 | 210 | { |
0d64f834 | 211 | struct stat_session *session = s->private; |
034939b6 | 212 | mutex_unlock(&session->stat_mutex); |
dbd0b4b3 FW |
213 | } |
214 | ||
215 | static int stat_seq_show(struct seq_file *s, void *v) | |
216 | { | |
0d64f834 | 217 | struct stat_session *session = s->private; |
8f184f27 | 218 | struct stat_node *l = container_of(v, struct stat_node, node); |
ff288b27 | 219 | |
e6f48901 LJ |
220 | if (v == SEQ_START_TOKEN) |
221 | return session->ts->stat_headers(s); | |
222 | ||
034939b6 | 223 | return session->ts->stat_show(s, l->stat); |
dbd0b4b3 FW |
224 | } |
225 | ||
226 | static const struct seq_operations trace_stat_seq_ops = { | |
55922173 IM |
227 | .start = stat_seq_start, |
228 | .next = stat_seq_next, | |
229 | .stop = stat_seq_stop, | |
230 | .show = stat_seq_show | |
dbd0b4b3 FW |
231 | }; |
232 | ||
034939b6 | 233 | /* The session stat is refilled and resorted at each stat file opening */ |
dbd0b4b3 FW |
234 | static int tracing_stat_open(struct inode *inode, struct file *file) |
235 | { | |
236 | int ret; | |
636eacee | 237 | struct seq_file *m; |
0d64f834 | 238 | struct stat_session *session = inode->i_private; |
034939b6 | 239 | |
636eacee LZ |
240 | ret = stat_seq_init(session); |
241 | if (ret) | |
242 | return ret; | |
243 | ||
dbd0b4b3 | 244 | ret = seq_open(file, &trace_stat_seq_ops); |
636eacee LZ |
245 | if (ret) { |
246 | reset_stat_session(session); | |
247 | return ret; | |
dbd0b4b3 FW |
248 | } |
249 | ||
636eacee LZ |
250 | m = file->private_data; |
251 | m->private = session; | |
dbd0b4b3 FW |
252 | return ret; |
253 | } | |
254 | ||
dbd0b4b3 | 255 | /* |
dbd3fbdf | 256 | * Avoid consuming memory with our now useless rbtree. |
dbd0b4b3 FW |
257 | */ |
258 | static int tracing_stat_release(struct inode *i, struct file *f) | |
259 | { | |
0d64f834 | 260 | struct stat_session *session = i->i_private; |
034939b6 | 261 | |
034939b6 | 262 | reset_stat_session(session); |
034939b6 | 263 | |
636eacee | 264 | return seq_release(i, f); |
dbd0b4b3 FW |
265 | } |
266 | ||
267 | static const struct file_operations tracing_stat_fops = { | |
268 | .open = tracing_stat_open, | |
269 | .read = seq_read, | |
270 | .llseek = seq_lseek, | |
271 | .release = tracing_stat_release | |
272 | }; | |
273 | ||
002bb86d | 274 | static int tracing_stat_init(void) |
dbd0b4b3 FW |
275 | { |
276 | struct dentry *d_tracing; | |
dbd0b4b3 | 277 | |
dbd0b4b3 | 278 | d_tracing = tracing_init_dentry(); |
ed6f1c99 NK |
279 | if (!d_tracing) |
280 | return 0; | |
dbd0b4b3 | 281 | |
034939b6 FW |
282 | stat_dir = debugfs_create_dir("trace_stat", d_tracing); |
283 | if (!stat_dir) | |
dbd0b4b3 FW |
284 | pr_warning("Could not create debugfs " |
285 | "'trace_stat' entry\n"); | |
286 | return 0; | |
287 | } | |
002bb86d | 288 | |
0d64f834 | 289 | static int init_stat_file(struct stat_session *session) |
002bb86d FW |
290 | { |
291 | if (!stat_dir && tracing_stat_init()) | |
292 | return -ENODEV; | |
293 | ||
294 | session->file = debugfs_create_file(session->ts->name, 0644, | |
295 | stat_dir, | |
296 | session, &tracing_stat_fops); | |
297 | if (!session->file) | |
298 | return -ENOMEM; | |
299 | return 0; | |
300 | } | |
55922173 IM |
301 | |
302 | int register_stat_tracer(struct tracer_stat *trace) | |
303 | { | |
43bd1236 | 304 | struct stat_session *session, *node; |
55922173 IM |
305 | int ret; |
306 | ||
307 | if (!trace) | |
308 | return -EINVAL; | |
309 | ||
310 | if (!trace->stat_start || !trace->stat_next || !trace->stat_show) | |
311 | return -EINVAL; | |
312 | ||
313 | /* Already registered? */ | |
314 | mutex_lock(&all_stat_sessions_mutex); | |
43bd1236 | 315 | list_for_each_entry(node, &all_stat_sessions, session_list) { |
55922173 IM |
316 | if (node->ts == trace) { |
317 | mutex_unlock(&all_stat_sessions_mutex); | |
318 | return -EINVAL; | |
319 | } | |
320 | } | |
321 | mutex_unlock(&all_stat_sessions_mutex); | |
322 | ||
323 | /* Init the session */ | |
8f184f27 | 324 | session = kzalloc(sizeof(*session), GFP_KERNEL); |
55922173 IM |
325 | if (!session) |
326 | return -ENOMEM; | |
327 | ||
328 | session->ts = trace; | |
329 | INIT_LIST_HEAD(&session->session_list); | |
55922173 | 330 | mutex_init(&session->stat_mutex); |
55922173 IM |
331 | |
332 | ret = init_stat_file(session); | |
333 | if (ret) { | |
334 | destroy_session(session); | |
335 | return ret; | |
336 | } | |
337 | ||
338 | /* Register */ | |
339 | mutex_lock(&all_stat_sessions_mutex); | |
340 | list_add_tail(&session->session_list, &all_stat_sessions); | |
341 | mutex_unlock(&all_stat_sessions_mutex); | |
342 | ||
343 | return 0; | |
344 | } | |
345 | ||
346 | void unregister_stat_tracer(struct tracer_stat *trace) | |
347 | { | |
0d64f834 | 348 | struct stat_session *node, *tmp; |
55922173 IM |
349 | |
350 | mutex_lock(&all_stat_sessions_mutex); | |
351 | list_for_each_entry_safe(node, tmp, &all_stat_sessions, session_list) { | |
352 | if (node->ts == trace) { | |
353 | list_del(&node->session_list); | |
354 | destroy_session(node); | |
355 | break; | |
356 | } | |
357 | } | |
358 | mutex_unlock(&all_stat_sessions_mutex); | |
359 | } |