projects/linux·blob v2.6.18 · refs

564 lines · 12.9 KiB

1/*
2 * taskstats.c - Export per-task statistics to userland
3 *
4 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
5 * (C) Balbir Singh, IBM Corp. 2006
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 */
18
19#include <linux/kernel.h>
20#include <linux/taskstats_kern.h>
21#include <linux/delayacct.h>
22#include <linux/cpumask.h>
23#include <linux/percpu.h>
24#include <net/genetlink.h>
25#include <asm/atomic.h>
26
27/*
28 * Maximum length of a cpumask that can be specified in
29 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
30 */
31#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
32
33static DEFINE_PER_CPU(__u32, taskstats_seqnum) = { 0 };
34static int family_registered;
35kmem_cache_t *taskstats_cache;
36
37static struct genl_family family = {
38 .id = GENL_ID_GENERATE,
39 .name = TASKSTATS_GENL_NAME,
40 .version = TASKSTATS_GENL_VERSION,
41 .maxattr = TASKSTATS_CMD_ATTR_MAX,
42};
43
44static struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1]
45__read_mostly = {
46 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
47 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
48 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
49 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
50
51struct listener {
52 struct list_head list;
53 pid_t pid;
54 char valid;
55};
56
57struct listener_list {
58 struct rw_semaphore sem;
59 struct list_head list;
60};
61static DEFINE_PER_CPU(struct listener_list, listener_array);
62
63enum actions {
64 REGISTER,
65 DEREGISTER,
66 CPU_DONT_CARE
67};
68
69static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
70 void **replyp, size_t size)
71{
72 struct sk_buff *skb;
73 void *reply;
74
75 /*
76 * If new attributes are added, please revisit this allocation
77 */
78 skb = nlmsg_new(size);
79 if (!skb)
80 return -ENOMEM;
81
82 if (!info) {
83 int seq = get_cpu_var(taskstats_seqnum)++;
84 put_cpu_var(taskstats_seqnum);
85
86 reply = genlmsg_put(skb, 0, seq,
87 family.id, 0, 0,
88 cmd, family.version);
89 } else
90 reply = genlmsg_put(skb, info->snd_pid, info->snd_seq,
91 family.id, 0, 0,
92 cmd, family.version);
93 if (reply == NULL) {
94 nlmsg_free(skb);
95 return -EINVAL;
96 }
97
98 *skbp = skb;
99 *replyp = reply;
100 return 0;
101}
102
103/*
104 * Send taskstats data in @skb to listener with nl_pid @pid
105 */
106static int send_reply(struct sk_buff *skb, pid_t pid)
107{
108 struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
109 void *reply = genlmsg_data(genlhdr);
110 int rc;
111
112 rc = genlmsg_end(skb, reply);
113 if (rc < 0) {
114 nlmsg_free(skb);
115 return rc;
116 }
117
118 return genlmsg_unicast(skb, pid);
119}
120
121/*
122 * Send taskstats data in @skb to listeners registered for @cpu's exit data
123 */
124static void send_cpu_listeners(struct sk_buff *skb, unsigned int cpu)
125{
126 struct genlmsghdr *genlhdr = nlmsg_data((struct nlmsghdr *)skb->data);
127 struct listener_list *listeners;
128 struct listener *s, *tmp;
129 struct sk_buff *skb_next, *skb_cur = skb;
130 void *reply = genlmsg_data(genlhdr);
131 int rc, delcount = 0;
132
133 rc = genlmsg_end(skb, reply);
134 if (rc < 0) {
135 nlmsg_free(skb);
136 return;
137 }
138
139 rc = 0;
140 listeners = &per_cpu(listener_array, cpu);
141 down_read(&listeners->sem);
142 list_for_each_entry(s, &listeners->list, list) {
143 skb_next = NULL;
144 if (!list_is_last(&s->list, &listeners->list)) {
145 skb_next = skb_clone(skb_cur, GFP_KERNEL);
146 if (!skb_next)
147 break;
148 }
149 rc = genlmsg_unicast(skb_cur, s->pid);
150 if (rc == -ECONNREFUSED) {
151 s->valid = 0;
152 delcount++;
153 }
154 skb_cur = skb_next;
155 }
156 up_read(&listeners->sem);
157
158 if (skb_cur)
159 nlmsg_free(skb_cur);
160
161 if (!delcount)
162 return;
163
164 /* Delete invalidated entries */
165 down_write(&listeners->sem);
166 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
167 if (!s->valid) {
168 list_del(&s->list);
169 kfree(s);
170 }
171 }
172 up_write(&listeners->sem);
173}
174
175static int fill_pid(pid_t pid, struct task_struct *pidtsk,
176 struct taskstats *stats)
177{
178 int rc = 0;
179 struct task_struct *tsk = pidtsk;
180
181 if (!pidtsk) {
182 read_lock(&tasklist_lock);
183 tsk = find_task_by_pid(pid);
184 if (!tsk) {
185 read_unlock(&tasklist_lock);
186 return -ESRCH;
187 }
188 get_task_struct(tsk);
189 read_unlock(&tasklist_lock);
190 } else
191 get_task_struct(tsk);
192
193 /*
194 * Each accounting subsystem adds calls to its functions to
195 * fill in relevant parts of struct taskstsats as follows
196 *
197 * per-task-foo(stats, tsk);
198 */
199
200 delayacct_add_tsk(stats, tsk);
201 stats->version = TASKSTATS_VERSION;
202
203 /* Define err: label here if needed */
204 put_task_struct(tsk);
205 return rc;
206
207}
208
209static int fill_tgid(pid_t tgid, struct task_struct *tgidtsk,
210 struct taskstats *stats)
211{
212 struct task_struct *tsk, *first;
213 unsigned long flags;
214
215 /*
216 * Add additional stats from live tasks except zombie thread group
217 * leaders who are already counted with the dead tasks
218 */
219 first = tgidtsk;
220 if (!first) {
221 read_lock(&tasklist_lock);
222 first = find_task_by_pid(tgid);
223 if (!first) {
224 read_unlock(&tasklist_lock);
225 return -ESRCH;
226 }
227 get_task_struct(first);
228 read_unlock(&tasklist_lock);
229 } else
230 get_task_struct(first);
231
232 /* Start with stats from dead tasks */
233 spin_lock_irqsave(&first->signal->stats_lock, flags);
234 if (first->signal->stats)
235 memcpy(stats, first->signal->stats, sizeof(*stats));
236 spin_unlock_irqrestore(&first->signal->stats_lock, flags);
237
238 tsk = first;
239 read_lock(&tasklist_lock);
240 do {
241 if (tsk->exit_state == EXIT_ZOMBIE && thread_group_leader(tsk))
242 continue;
243 /*
244 * Accounting subsystem can call its functions here to
245 * fill in relevant parts of struct taskstsats as follows
246 *
247 * per-task-foo(stats, tsk);
248 */
249 delayacct_add_tsk(stats, tsk);
250
251 } while_each_thread(first, tsk);
252 read_unlock(&tasklist_lock);
253 stats->version = TASKSTATS_VERSION;
254
255 /*
256 * Accounting subsytems can also add calls here to modify
257 * fields of taskstats.
258 */
259
260 return 0;
261}
262
263
264static void fill_tgid_exit(struct task_struct *tsk)
265{
266 unsigned long flags;
267
268 spin_lock_irqsave(&tsk->signal->stats_lock, flags);
269 if (!tsk->signal->stats)
270 goto ret;
271
272 /*
273 * Each accounting subsystem calls its functions here to
274 * accumalate its per-task stats for tsk, into the per-tgid structure
275 *
276 * per-task-foo(tsk->signal->stats, tsk);
277 */
278 delayacct_add_tsk(tsk->signal->stats, tsk);
279ret:
280 spin_unlock_irqrestore(&tsk->signal->stats_lock, flags);
281 return;
282}
283
284static int add_del_listener(pid_t pid, cpumask_t *maskp, int isadd)
285{
286 struct listener_list *listeners;
287 struct listener *s, *tmp;
288 unsigned int cpu;
289 cpumask_t mask = *maskp;
290
291 if (!cpus_subset(mask, cpu_possible_map))
292 return -EINVAL;
293
294 if (isadd == REGISTER) {
295 for_each_cpu_mask(cpu, mask) {
296 s = kmalloc_node(sizeof(struct listener), GFP_KERNEL,
297 cpu_to_node(cpu));
298 if (!s)
299 goto cleanup;
300 s->pid = pid;
301 INIT_LIST_HEAD(&s->list);
302 s->valid = 1;
303
304 listeners = &per_cpu(listener_array, cpu);
305 down_write(&listeners->sem);
306 list_add(&s->list, &listeners->list);
307 up_write(&listeners->sem);
308 }
309 return 0;
310 }
311
312 /* Deregister or cleanup */
313cleanup:
314 for_each_cpu_mask(cpu, mask) {
315 listeners = &per_cpu(listener_array, cpu);
316 down_write(&listeners->sem);
317 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
318 if (s->pid == pid) {
319 list_del(&s->list);
320 kfree(s);
321 break;
322 }
323 }
324 up_write(&listeners->sem);
325 }
326 return 0;
327}
328
329static int parse(struct nlattr *na, cpumask_t *mask)
330{
331 char *data;
332 int len;
333 int ret;
334
335 if (na == NULL)
336 return 1;
337 len = nla_len(na);
338 if (len > TASKSTATS_CPUMASK_MAXLEN)
339 return -E2BIG;
340 if (len < 1)
341 return -EINVAL;
342 data = kmalloc(len, GFP_KERNEL);
343 if (!data)
344 return -ENOMEM;
345 nla_strlcpy(data, na, len);
346 ret = cpulist_parse(data, *mask);
347 kfree(data);
348 return ret;
349}
350
351static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
352{
353 int rc = 0;
354 struct sk_buff *rep_skb;
355 struct taskstats stats;
356 void *reply;
357 size_t size;
358 struct nlattr *na;
359 cpumask_t mask;
360
361 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], &mask);
362 if (rc < 0)
363 return rc;
364 if (rc == 0)
365 return add_del_listener(info->snd_pid, &mask, REGISTER);
366
367 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], &mask);
368 if (rc < 0)
369 return rc;
370 if (rc == 0)
371 return add_del_listener(info->snd_pid, &mask, DEREGISTER);
372
373 /*
374 * Size includes space for nested attributes
375 */
376 size = nla_total_size(sizeof(u32)) +
377 nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
378
379 memset(&stats, 0, sizeof(stats));
380 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
381 if (rc < 0)
382 return rc;
383
384 if (info->attrs[TASKSTATS_CMD_ATTR_PID]) {
385 u32 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
386 rc = fill_pid(pid, NULL, &stats);
387 if (rc < 0)
388 goto err;
389
390 na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_PID);
391 NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_PID, pid);
392 NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
393 stats);
394 } else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) {
395 u32 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
396 rc = fill_tgid(tgid, NULL, &stats);
397 if (rc < 0)
398 goto err;
399
400 na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_TGID);
401 NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_TGID, tgid);
402 NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
403 stats);
404 } else {
405 rc = -EINVAL;
406 goto err;
407 }
408
409 nla_nest_end(rep_skb, na);
410
411 return send_reply(rep_skb, info->snd_pid);
412
413nla_put_failure:
414 return genlmsg_cancel(rep_skb, reply);
415err:
416 nlmsg_free(rep_skb);
417 return rc;
418}
419
420void taskstats_exit_alloc(struct taskstats **ptidstats, unsigned int *mycpu)
421{
422 struct listener_list *listeners;
423 struct taskstats *tmp;
424 /*
425 * This is the cpu on which the task is exiting currently and will
426 * be the one for which the exit event is sent, even if the cpu
427 * on which this function is running changes later.
428 */
429 *mycpu = raw_smp_processor_id();
430
431 *ptidstats = NULL;
432 tmp = kmem_cache_zalloc(taskstats_cache, SLAB_KERNEL);
433 if (!tmp)
434 return;
435
436 listeners = &per_cpu(listener_array, *mycpu);
437 down_read(&listeners->sem);
438 if (!list_empty(&listeners->list)) {
439 *ptidstats = tmp;
440 tmp = NULL;
441 }
442 up_read(&listeners->sem);
443 kfree(tmp);
444}
445
446/* Send pid data out on exit */
447void taskstats_exit_send(struct task_struct *tsk, struct taskstats *tidstats,
448 int group_dead, unsigned int mycpu)
449{
450 int rc;
451 struct sk_buff *rep_skb;
452 void *reply;
453 size_t size;
454 int is_thread_group;
455 struct nlattr *na;
456 unsigned long flags;
457
458 if (!family_registered || !tidstats)
459 return;
460
461 spin_lock_irqsave(&tsk->signal->stats_lock, flags);
462 is_thread_group = tsk->signal->stats ? 1 : 0;
463 spin_unlock_irqrestore(&tsk->signal->stats_lock, flags);
464
465 rc = 0;
466 /*
467 * Size includes space for nested attributes
468 */
469 size = nla_total_size(sizeof(u32)) +
470 nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
471
472 if (is_thread_group)
473 size = 2 * size; /* PID + STATS + TGID + STATS */
474
475 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, &reply, size);
476 if (rc < 0)
477 goto ret;
478
479 rc = fill_pid(tsk->pid, tsk, tidstats);
480 if (rc < 0)
481 goto err_skb;
482
483 na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_PID);
484 NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_PID, (u32)tsk->pid);
485 NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
486 *tidstats);
487 nla_nest_end(rep_skb, na);
488
489 if (!is_thread_group)
490 goto send;
491
492 /*
493 * tsk has/had a thread group so fill the tsk->signal->stats structure
494 * Doesn't matter if tsk is the leader or the last group member leaving
495 */
496
497 fill_tgid_exit(tsk);
498 if (!group_dead)
499 goto send;
500
501 na = nla_nest_start(rep_skb, TASKSTATS_TYPE_AGGR_TGID);
502 NLA_PUT_U32(rep_skb, TASKSTATS_TYPE_TGID, (u32)tsk->tgid);
503 /* No locking needed for tsk->signal->stats since group is dead */
504 NLA_PUT_TYPE(rep_skb, struct taskstats, TASKSTATS_TYPE_STATS,
505 *tsk->signal->stats);
506 nla_nest_end(rep_skb, na);
507
508send:
509 send_cpu_listeners(rep_skb, mycpu);
510 return;
511
512nla_put_failure:
513 genlmsg_cancel(rep_skb, reply);
514 goto ret;
515err_skb:
516 nlmsg_free(rep_skb);
517ret:
518 return;
519}
520
521static struct genl_ops taskstats_ops = {
522 .cmd = TASKSTATS_CMD_GET,
523 .doit = taskstats_user_cmd,
524 .policy = taskstats_cmd_get_policy,
525};
526
527/* Needed early in initialization */
528void __init taskstats_init_early(void)
529{
530 unsigned int i;
531
532 taskstats_cache = kmem_cache_create("taskstats_cache",
533 sizeof(struct taskstats),
534 0, SLAB_PANIC, NULL, NULL);
535 for_each_possible_cpu(i) {
536 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
537 init_rwsem(&(per_cpu(listener_array, i).sem));
538 }
539}
540
541static int __init taskstats_init(void)
542{
543 int rc;
544
545 rc = genl_register_family(&family);
546 if (rc)
547 return rc;
548
549 rc = genl_register_ops(&family, &taskstats_ops);
550 if (rc < 0)
551 goto err;
552
553 family_registered = 1;
554 return 0;
555err:
556 genl_unregister_family(&family);
557 return rc;
558}
559
560/*
561 * late initcall ensures initialization of statistics collection
562 * mechanisms precedes initialization of the taskstats interface
563 */
564late_initcall(taskstats_init);