projects/linux·blob v2.6.34-rc6 · refs

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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/tsacct_kern.h>
22#include <linux/delayacct.h>
23#include <linux/cpumask.h>
24#include <linux/percpu.h>
25#include <linux/slab.h>
26#include <linux/cgroupstats.h>
27#include <linux/cgroup.h>
28#include <linux/fs.h>
29#include <linux/file.h>
30#include <net/genetlink.h>
31#include <asm/atomic.h>
32
33/*
34 * Maximum length of a cpumask that can be specified in
35 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
36 */
37#define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
38
39static DEFINE_PER_CPU(__u32, taskstats_seqnum);
40static int family_registered;
41struct kmem_cache *taskstats_cache;
42
43static struct genl_family family = {
44 .id = GENL_ID_GENERATE,
45 .name = TASKSTATS_GENL_NAME,
46 .version = TASKSTATS_GENL_VERSION,
47 .maxattr = TASKSTATS_CMD_ATTR_MAX,
48};
49
50static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
51 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
52 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
53 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
54 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
55
56static const struct nla_policy cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] = {
57 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
58};
59
60struct listener {
61 struct list_head list;
62 pid_t pid;
63 char valid;
64};
65
66struct listener_list {
67 struct rw_semaphore sem;
68 struct list_head list;
69};
70static DEFINE_PER_CPU(struct listener_list, listener_array);
71
72enum actions {
73 REGISTER,
74 DEREGISTER,
75 CPU_DONT_CARE
76};
77
78static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
79 size_t size)
80{
81 struct sk_buff *skb;
82 void *reply;
83
84 /*
85 * If new attributes are added, please revisit this allocation
86 */
87 skb = genlmsg_new(size, GFP_KERNEL);
88 if (!skb)
89 return -ENOMEM;
90
91 if (!info) {
92 int seq = get_cpu_var(taskstats_seqnum)++;
93 put_cpu_var(taskstats_seqnum);
94
95 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
96 } else
97 reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
98 if (reply == NULL) {
99 nlmsg_free(skb);
100 return -EINVAL;
101 }
102
103 *skbp = skb;
104 return 0;
105}
106
107/*
108 * Send taskstats data in @skb to listener with nl_pid @pid
109 */
110static int send_reply(struct sk_buff *skb, struct genl_info *info)
111{
112 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
113 void *reply = genlmsg_data(genlhdr);
114 int rc;
115
116 rc = genlmsg_end(skb, reply);
117 if (rc < 0) {
118 nlmsg_free(skb);
119 return rc;
120 }
121
122 return genlmsg_reply(skb, info);
123}
124
125/*
126 * Send taskstats data in @skb to listeners registered for @cpu's exit data
127 */
128static void send_cpu_listeners(struct sk_buff *skb,
129 struct listener_list *listeners)
130{
131 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
132 struct listener *s, *tmp;
133 struct sk_buff *skb_next, *skb_cur = skb;
134 void *reply = genlmsg_data(genlhdr);
135 int rc, delcount = 0;
136
137 rc = genlmsg_end(skb, reply);
138 if (rc < 0) {
139 nlmsg_free(skb);
140 return;
141 }
142
143 rc = 0;
144 down_read(&listeners->sem);
145 list_for_each_entry(s, &listeners->list, list) {
146 skb_next = NULL;
147 if (!list_is_last(&s->list, &listeners->list)) {
148 skb_next = skb_clone(skb_cur, GFP_KERNEL);
149 if (!skb_next)
150 break;
151 }
152 rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
153 if (rc == -ECONNREFUSED) {
154 s->valid = 0;
155 delcount++;
156 }
157 skb_cur = skb_next;
158 }
159 up_read(&listeners->sem);
160
161 if (skb_cur)
162 nlmsg_free(skb_cur);
163
164 if (!delcount)
165 return;
166
167 /* Delete invalidated entries */
168 down_write(&listeners->sem);
169 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
170 if (!s->valid) {
171 list_del(&s->list);
172 kfree(s);
173 }
174 }
175 up_write(&listeners->sem);
176}
177
178static int fill_pid(pid_t pid, struct task_struct *tsk,
179 struct taskstats *stats)
180{
181 int rc = 0;
182
183 if (!tsk) {
184 rcu_read_lock();
185 tsk = find_task_by_vpid(pid);
186 if (tsk)
187 get_task_struct(tsk);
188 rcu_read_unlock();
189 if (!tsk)
190 return -ESRCH;
191 } else
192 get_task_struct(tsk);
193
194 memset(stats, 0, sizeof(*stats));
195 /*
196 * Each accounting subsystem adds calls to its functions to
197 * fill in relevant parts of struct taskstsats as follows
198 *
199 * per-task-foo(stats, tsk);
200 */
201
202 delayacct_add_tsk(stats, tsk);
203
204 /* fill in basic acct fields */
205 stats->version = TASKSTATS_VERSION;
206 stats->nvcsw = tsk->nvcsw;
207 stats->nivcsw = tsk->nivcsw;
208 bacct_add_tsk(stats, tsk);
209
210 /* fill in extended acct fields */
211 xacct_add_tsk(stats, tsk);
212
213 /* Define err: label here if needed */
214 put_task_struct(tsk);
215 return rc;
216
217}
218
219static int fill_tgid(pid_t tgid, struct task_struct *first,
220 struct taskstats *stats)
221{
222 struct task_struct *tsk;
223 unsigned long flags;
224 int rc = -ESRCH;
225
226 /*
227 * Add additional stats from live tasks except zombie thread group
228 * leaders who are already counted with the dead tasks
229 */
230 rcu_read_lock();
231 if (!first)
232 first = find_task_by_vpid(tgid);
233
234 if (!first || !lock_task_sighand(first, &flags))
235 goto out;
236
237 if (first->signal->stats)
238 memcpy(stats, first->signal->stats, sizeof(*stats));
239 else
240 memset(stats, 0, sizeof(*stats));
241
242 tsk = first;
243 do {
244 if (tsk->exit_state)
245 continue;
246 /*
247 * Accounting subsystem can call its functions here to
248 * fill in relevant parts of struct taskstsats as follows
249 *
250 * per-task-foo(stats, tsk);
251 */
252 delayacct_add_tsk(stats, tsk);
253
254 stats->nvcsw += tsk->nvcsw;
255 stats->nivcsw += tsk->nivcsw;
256 } while_each_thread(first, tsk);
257
258 unlock_task_sighand(first, &flags);
259 rc = 0;
260out:
261 rcu_read_unlock();
262
263 stats->version = TASKSTATS_VERSION;
264 /*
265 * Accounting subsystems can also add calls here to modify
266 * fields of taskstats.
267 */
268 return rc;
269}
270
271
272static void fill_tgid_exit(struct task_struct *tsk)
273{
274 unsigned long flags;
275
276 spin_lock_irqsave(&tsk->sighand->siglock, flags);
277 if (!tsk->signal->stats)
278 goto ret;
279
280 /*
281 * Each accounting subsystem calls its functions here to
282 * accumalate its per-task stats for tsk, into the per-tgid structure
283 *
284 * per-task-foo(tsk->signal->stats, tsk);
285 */
286 delayacct_add_tsk(tsk->signal->stats, tsk);
287ret:
288 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
289 return;
290}
291
292static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
293{
294 struct listener_list *listeners;
295 struct listener *s, *tmp;
296 unsigned int cpu;
297
298 if (!cpumask_subset(mask, cpu_possible_mask))
299 return -EINVAL;
300
301 if (isadd == REGISTER) {
302 for_each_cpu(cpu, mask) {
303 s = kmalloc_node(sizeof(struct listener), GFP_KERNEL,
304 cpu_to_node(cpu));
305 if (!s)
306 goto cleanup;
307 s->pid = pid;
308 INIT_LIST_HEAD(&s->list);
309 s->valid = 1;
310
311 listeners = &per_cpu(listener_array, cpu);
312 down_write(&listeners->sem);
313 list_add(&s->list, &listeners->list);
314 up_write(&listeners->sem);
315 }
316 return 0;
317 }
318
319 /* Deregister or cleanup */
320cleanup:
321 for_each_cpu(cpu, mask) {
322 listeners = &per_cpu(listener_array, cpu);
323 down_write(&listeners->sem);
324 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
325 if (s->pid == pid) {
326 list_del(&s->list);
327 kfree(s);
328 break;
329 }
330 }
331 up_write(&listeners->sem);
332 }
333 return 0;
334}
335
336static int parse(struct nlattr *na, struct cpumask *mask)
337{
338 char *data;
339 int len;
340 int ret;
341
342 if (na == NULL)
343 return 1;
344 len = nla_len(na);
345 if (len > TASKSTATS_CPUMASK_MAXLEN)
346 return -E2BIG;
347 if (len < 1)
348 return -EINVAL;
349 data = kmalloc(len, GFP_KERNEL);
350 if (!data)
351 return -ENOMEM;
352 nla_strlcpy(data, na, len);
353 ret = cpulist_parse(data, mask);
354 kfree(data);
355 return ret;
356}
357
358static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
359{
360 struct nlattr *na, *ret;
361 int aggr;
362
363 aggr = (type == TASKSTATS_TYPE_PID)
364 ? TASKSTATS_TYPE_AGGR_PID
365 : TASKSTATS_TYPE_AGGR_TGID;
366
367 na = nla_nest_start(skb, aggr);
368 if (!na)
369 goto err;
370 if (nla_put(skb, type, sizeof(pid), &pid) < 0)
371 goto err;
372 ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));
373 if (!ret)
374 goto err;
375 nla_nest_end(skb, na);
376
377 return nla_data(ret);
378err:
379 return NULL;
380}
381
382static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
383{
384 int rc = 0;
385 struct sk_buff *rep_skb;
386 struct cgroupstats *stats;
387 struct nlattr *na;
388 size_t size;
389 u32 fd;
390 struct file *file;
391 int fput_needed;
392
393 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
394 if (!na)
395 return -EINVAL;
396
397 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
398 file = fget_light(fd, &fput_needed);
399 if (!file)
400 return 0;
401
402 size = nla_total_size(sizeof(struct cgroupstats));
403
404 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
405 size);
406 if (rc < 0)
407 goto err;
408
409 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
410 sizeof(struct cgroupstats));
411 stats = nla_data(na);
412 memset(stats, 0, sizeof(*stats));
413
414 rc = cgroupstats_build(stats, file->f_dentry);
415 if (rc < 0) {
416 nlmsg_free(rep_skb);
417 goto err;
418 }
419
420 rc = send_reply(rep_skb, info);
421
422err:
423 fput_light(file, fput_needed);
424 return rc;
425}
426
427static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
428{
429 int rc;
430 struct sk_buff *rep_skb;
431 struct taskstats *stats;
432 size_t size;
433 cpumask_var_t mask;
434
435 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
436 return -ENOMEM;
437
438 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
439 if (rc < 0)
440 goto free_return_rc;
441 if (rc == 0) {
442 rc = add_del_listener(info->snd_pid, mask, REGISTER);
443 goto free_return_rc;
444 }
445
446 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
447 if (rc < 0)
448 goto free_return_rc;
449 if (rc == 0) {
450 rc = add_del_listener(info->snd_pid, mask, DEREGISTER);
451free_return_rc:
452 free_cpumask_var(mask);
453 return rc;
454 }
455 free_cpumask_var(mask);
456
457 /*
458 * Size includes space for nested attributes
459 */
460 size = nla_total_size(sizeof(u32)) +
461 nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
462
463 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
464 if (rc < 0)
465 return rc;
466
467 rc = -EINVAL;
468 if (info->attrs[TASKSTATS_CMD_ATTR_PID]) {
469 u32 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
470 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
471 if (!stats)
472 goto err;
473
474 rc = fill_pid(pid, NULL, stats);
475 if (rc < 0)
476 goto err;
477 } else if (info->attrs[TASKSTATS_CMD_ATTR_TGID]) {
478 u32 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
479 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
480 if (!stats)
481 goto err;
482
483 rc = fill_tgid(tgid, NULL, stats);
484 if (rc < 0)
485 goto err;
486 } else
487 goto err;
488
489 return send_reply(rep_skb, info);
490err:
491 nlmsg_free(rep_skb);
492 return rc;
493}
494
495static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
496{
497 struct signal_struct *sig = tsk->signal;
498 struct taskstats *stats;
499
500 if (sig->stats || thread_group_empty(tsk))
501 goto ret;
502
503 /* No problem if kmem_cache_zalloc() fails */
504 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
505
506 spin_lock_irq(&tsk->sighand->siglock);
507 if (!sig->stats) {
508 sig->stats = stats;
509 stats = NULL;
510 }
511 spin_unlock_irq(&tsk->sighand->siglock);
512
513 if (stats)
514 kmem_cache_free(taskstats_cache, stats);
515ret:
516 return sig->stats;
517}
518
519/* Send pid data out on exit */
520void taskstats_exit(struct task_struct *tsk, int group_dead)
521{
522 int rc;
523 struct listener_list *listeners;
524 struct taskstats *stats;
525 struct sk_buff *rep_skb;
526 size_t size;
527 int is_thread_group;
528
529 if (!family_registered)
530 return;
531
532 /*
533 * Size includes space for nested attributes
534 */
535 size = nla_total_size(sizeof(u32)) +
536 nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
537
538 is_thread_group = !!taskstats_tgid_alloc(tsk);
539 if (is_thread_group) {
540 /* PID + STATS + TGID + STATS */
541 size = 2 * size;
542 /* fill the tsk->signal->stats structure */
543 fill_tgid_exit(tsk);
544 }
545
546 listeners = &__raw_get_cpu_var(listener_array);
547 if (list_empty(&listeners->list))
548 return;
549
550 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
551 if (rc < 0)
552 return;
553
554 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, tsk->pid);
555 if (!stats)
556 goto err;
557
558 rc = fill_pid(-1, tsk, stats);
559 if (rc < 0)
560 goto err;
561
562 /*
563 * Doesn't matter if tsk is the leader or the last group member leaving
564 */
565 if (!is_thread_group || !group_dead)
566 goto send;
567
568 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tsk->tgid);
569 if (!stats)
570 goto err;
571
572 memcpy(stats, tsk->signal->stats, sizeof(*stats));
573
574send:
575 send_cpu_listeners(rep_skb, listeners);
576 return;
577err:
578 nlmsg_free(rep_skb);
579}
580
581static struct genl_ops taskstats_ops = {
582 .cmd = TASKSTATS_CMD_GET,
583 .doit = taskstats_user_cmd,
584 .policy = taskstats_cmd_get_policy,
585};
586
587static struct genl_ops cgroupstats_ops = {
588 .cmd = CGROUPSTATS_CMD_GET,
589 .doit = cgroupstats_user_cmd,
590 .policy = cgroupstats_cmd_get_policy,
591};
592
593/* Needed early in initialization */
594void __init taskstats_init_early(void)
595{
596 unsigned int i;
597
598 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
599 for_each_possible_cpu(i) {
600 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
601 init_rwsem(&(per_cpu(listener_array, i).sem));
602 }
603}
604
605static int __init taskstats_init(void)
606{
607 int rc;
608
609 rc = genl_register_family(&family);
610 if (rc)
611 return rc;
612
613 rc = genl_register_ops(&family, &taskstats_ops);
614 if (rc < 0)
615 goto err;
616
617 rc = genl_register_ops(&family, &cgroupstats_ops);
618 if (rc < 0)
619 goto err_cgroup_ops;
620
621 family_registered = 1;
622 printk("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
623 return 0;
624err_cgroup_ops:
625 genl_unregister_ops(&family, &taskstats_ops);
626err:
627 genl_unregister_family(&family);
628 return rc;
629}
630
631/*
632 * late initcall ensures initialization of statistics collection
633 * mechanisms precedes initialization of the taskstats interface
634 */
635late_initcall(taskstats_init);