1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * taskstats.c - Export per-task statistics to userland
5 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
6 * (C) Balbir Singh, IBM Corp. 2006
9 #include <linux/kernel.h>
10 #include <linux/taskstats_kern.h>
11 #include <linux/tsacct_kern.h>
12 #include <linux/delayacct.h>
13 #include <linux/cpumask.h>
14 #include <linux/percpu.h>
15 #include <linux/slab.h>
16 #include <linux/cgroupstats.h>
17 #include <linux/cgroup.h>
19 #include <linux/file.h>
20 #include <linux/pid_namespace.h>
21 #include <net/genetlink.h>
22 #include <linux/atomic.h>
23 #include <linux/sched/cputime.h>
26 * Maximum length of a cpumask that can be specified in
27 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
29 #define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
31 static DEFINE_PER_CPU(__u32
, taskstats_seqnum
);
32 static int family_registered
;
33 struct kmem_cache
*taskstats_cache
;
35 static struct genl_family family
;
37 static const struct nla_policy taskstats_cmd_get_policy
[] = {
38 [TASKSTATS_CMD_ATTR_PID
] = { .type
= NLA_U32
},
39 [TASKSTATS_CMD_ATTR_TGID
] = { .type
= NLA_U32
},
40 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK
] = { .type
= NLA_STRING
},
41 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK
] = { .type
= NLA_STRING
},};
43 static const struct nla_policy cgroupstats_cmd_get_policy
[] = {
44 [CGROUPSTATS_CMD_ATTR_FD
] = { .type
= NLA_U32
},
48 struct list_head list
;
53 struct listener_list
{
54 struct rw_semaphore sem
;
55 struct list_head list
;
57 static DEFINE_PER_CPU(struct listener_list
, listener_array
);
65 static int prepare_reply(struct genl_info
*info
, u8 cmd
, struct sk_buff
**skbp
,
72 * If new attributes are added, please revisit this allocation
74 skb
= genlmsg_new(size
, GFP_KERNEL
);
79 int seq
= this_cpu_inc_return(taskstats_seqnum
) - 1;
81 reply
= genlmsg_put(skb
, 0, seq
, &family
, 0, cmd
);
83 reply
= genlmsg_put_reply(skb
, info
, &family
, 0, cmd
);
94 * Send taskstats data in @skb to listener with nl_pid @pid
96 static int send_reply(struct sk_buff
*skb
, struct genl_info
*info
)
98 struct genlmsghdr
*genlhdr
= nlmsg_data(nlmsg_hdr(skb
));
99 void *reply
= genlmsg_data(genlhdr
);
101 genlmsg_end(skb
, reply
);
103 return genlmsg_reply(skb
, info
);
107 * Send taskstats data in @skb to listeners registered for @cpu's exit data
109 static void send_cpu_listeners(struct sk_buff
*skb
,
110 struct listener_list
*listeners
)
112 struct genlmsghdr
*genlhdr
= nlmsg_data(nlmsg_hdr(skb
));
113 struct listener
*s
, *tmp
;
114 struct sk_buff
*skb_next
, *skb_cur
= skb
;
115 void *reply
= genlmsg_data(genlhdr
);
116 int rc
, delcount
= 0;
118 genlmsg_end(skb
, reply
);
121 down_read(&listeners
->sem
);
122 list_for_each_entry(s
, &listeners
->list
, list
) {
124 if (!list_is_last(&s
->list
, &listeners
->list
)) {
125 skb_next
= skb_clone(skb_cur
, GFP_KERNEL
);
129 rc
= genlmsg_unicast(&init_net
, skb_cur
, s
->pid
);
130 if (rc
== -ECONNREFUSED
) {
136 up_read(&listeners
->sem
);
144 /* Delete invalidated entries */
145 down_write(&listeners
->sem
);
146 list_for_each_entry_safe(s
, tmp
, &listeners
->list
, list
) {
152 up_write(&listeners
->sem
);
155 static void fill_stats(struct user_namespace
*user_ns
,
156 struct pid_namespace
*pid_ns
,
157 struct task_struct
*tsk
, struct taskstats
*stats
)
159 memset(stats
, 0, sizeof(*stats
));
161 * Each accounting subsystem adds calls to its functions to
162 * fill in relevant parts of struct taskstsats as follows
164 * per-task-foo(stats, tsk);
167 delayacct_add_tsk(stats
, tsk
);
169 /* fill in basic acct fields */
170 stats
->version
= TASKSTATS_VERSION
;
171 stats
->nvcsw
= tsk
->nvcsw
;
172 stats
->nivcsw
= tsk
->nivcsw
;
173 bacct_add_tsk(user_ns
, pid_ns
, stats
, tsk
);
175 /* fill in extended acct fields */
176 xacct_add_tsk(stats
, tsk
);
179 static int fill_stats_for_pid(pid_t pid
, struct taskstats
*stats
)
181 struct task_struct
*tsk
;
183 tsk
= find_get_task_by_vpid(pid
);
186 fill_stats(current_user_ns(), task_active_pid_ns(current
), tsk
, stats
);
187 put_task_struct(tsk
);
191 static int fill_stats_for_tgid(pid_t tgid
, struct taskstats
*stats
)
193 struct task_struct
*tsk
, *first
;
196 u64 delta
, utime
, stime
;
200 * Add additional stats from live tasks except zombie thread group
201 * leaders who are already counted with the dead tasks
204 first
= find_task_by_vpid(tgid
);
206 if (!first
|| !lock_task_sighand(first
, &flags
))
209 if (first
->signal
->stats
)
210 memcpy(stats
, first
->signal
->stats
, sizeof(*stats
));
212 memset(stats
, 0, sizeof(*stats
));
215 start_time
= ktime_get_ns();
220 * Accounting subsystem can call its functions here to
221 * fill in relevant parts of struct taskstsats as follows
223 * per-task-foo(stats, tsk);
225 delayacct_add_tsk(stats
, tsk
);
227 /* calculate task elapsed time in nsec */
228 delta
= start_time
- tsk
->start_time
;
229 /* Convert to micro seconds */
230 do_div(delta
, NSEC_PER_USEC
);
231 stats
->ac_etime
+= delta
;
233 task_cputime(tsk
, &utime
, &stime
);
234 stats
->ac_utime
+= div_u64(utime
, NSEC_PER_USEC
);
235 stats
->ac_stime
+= div_u64(stime
, NSEC_PER_USEC
);
237 stats
->nvcsw
+= tsk
->nvcsw
;
238 stats
->nivcsw
+= tsk
->nivcsw
;
239 } while_each_thread(first
, tsk
);
241 unlock_task_sighand(first
, &flags
);
246 stats
->version
= TASKSTATS_VERSION
;
248 * Accounting subsystems can also add calls here to modify
249 * fields of taskstats.
254 static void fill_tgid_exit(struct task_struct
*tsk
)
258 spin_lock_irqsave(&tsk
->sighand
->siglock
, flags
);
259 if (!tsk
->signal
->stats
)
263 * Each accounting subsystem calls its functions here to
264 * accumalate its per-task stats for tsk, into the per-tgid structure
266 * per-task-foo(tsk->signal->stats, tsk);
268 delayacct_add_tsk(tsk
->signal
->stats
, tsk
);
270 spin_unlock_irqrestore(&tsk
->sighand
->siglock
, flags
);
274 static int add_del_listener(pid_t pid
, const struct cpumask
*mask
, int isadd
)
276 struct listener_list
*listeners
;
277 struct listener
*s
, *tmp
, *s2
;
281 if (!cpumask_subset(mask
, cpu_possible_mask
))
284 if (current_user_ns() != &init_user_ns
)
287 if (task_active_pid_ns(current
) != &init_pid_ns
)
290 if (isadd
== REGISTER
) {
291 for_each_cpu(cpu
, mask
) {
292 s
= kmalloc_node(sizeof(struct listener
),
293 GFP_KERNEL
, cpu_to_node(cpu
));
301 listeners
= &per_cpu(listener_array
, cpu
);
302 down_write(&listeners
->sem
);
303 list_for_each_entry(s2
, &listeners
->list
, list
) {
304 if (s2
->pid
== pid
&& s2
->valid
)
307 list_add(&s
->list
, &listeners
->list
);
310 up_write(&listeners
->sem
);
311 kfree(s
); /* nop if NULL */
316 /* Deregister or cleanup */
318 for_each_cpu(cpu
, mask
) {
319 listeners
= &per_cpu(listener_array
, cpu
);
320 down_write(&listeners
->sem
);
321 list_for_each_entry_safe(s
, tmp
, &listeners
->list
, list
) {
328 up_write(&listeners
->sem
);
333 static int parse(struct nlattr
*na
, struct cpumask
*mask
)
342 if (len
> TASKSTATS_CPUMASK_MAXLEN
)
346 data
= kmalloc(len
, GFP_KERNEL
);
349 nla_strscpy(data
, na
, len
);
350 ret
= cpulist_parse(data
, mask
);
355 static struct taskstats
*mk_reply(struct sk_buff
*skb
, int type
, u32 pid
)
357 struct nlattr
*na
, *ret
;
360 aggr
= (type
== TASKSTATS_TYPE_PID
)
361 ? TASKSTATS_TYPE_AGGR_PID
362 : TASKSTATS_TYPE_AGGR_TGID
;
364 na
= nla_nest_start_noflag(skb
, aggr
);
368 if (nla_put(skb
, type
, sizeof(pid
), &pid
) < 0) {
369 nla_nest_cancel(skb
, na
);
372 ret
= nla_reserve_64bit(skb
, TASKSTATS_TYPE_STATS
,
373 sizeof(struct taskstats
), TASKSTATS_TYPE_NULL
);
375 nla_nest_cancel(skb
, na
);
378 nla_nest_end(skb
, na
);
380 return nla_data(ret
);
385 static int cgroupstats_user_cmd(struct sk_buff
*skb
, struct genl_info
*info
)
388 struct sk_buff
*rep_skb
;
389 struct cgroupstats
*stats
;
395 na
= info
->attrs
[CGROUPSTATS_CMD_ATTR_FD
];
399 fd
= nla_get_u32(info
->attrs
[CGROUPSTATS_CMD_ATTR_FD
]);
404 size
= nla_total_size(sizeof(struct cgroupstats
));
406 rc
= prepare_reply(info
, CGROUPSTATS_CMD_NEW
, &rep_skb
,
411 na
= nla_reserve(rep_skb
, CGROUPSTATS_TYPE_CGROUP_STATS
,
412 sizeof(struct cgroupstats
));
419 stats
= nla_data(na
);
420 memset(stats
, 0, sizeof(*stats
));
422 rc
= cgroupstats_build(stats
, f
.file
->f_path
.dentry
);
428 rc
= send_reply(rep_skb
, info
);
435 static int cmd_attr_register_cpumask(struct genl_info
*info
)
440 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
442 rc
= parse(info
->attrs
[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK
], mask
);
445 rc
= add_del_listener(info
->snd_portid
, mask
, REGISTER
);
447 free_cpumask_var(mask
);
451 static int cmd_attr_deregister_cpumask(struct genl_info
*info
)
456 if (!alloc_cpumask_var(&mask
, GFP_KERNEL
))
458 rc
= parse(info
->attrs
[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK
], mask
);
461 rc
= add_del_listener(info
->snd_portid
, mask
, DEREGISTER
);
463 free_cpumask_var(mask
);
467 static size_t taskstats_packet_size(void)
471 size
= nla_total_size(sizeof(u32
)) +
472 nla_total_size_64bit(sizeof(struct taskstats
)) +
478 static int cmd_attr_pid(struct genl_info
*info
)
480 struct taskstats
*stats
;
481 struct sk_buff
*rep_skb
;
486 size
= taskstats_packet_size();
488 rc
= prepare_reply(info
, TASKSTATS_CMD_NEW
, &rep_skb
, size
);
493 pid
= nla_get_u32(info
->attrs
[TASKSTATS_CMD_ATTR_PID
]);
494 stats
= mk_reply(rep_skb
, TASKSTATS_TYPE_PID
, pid
);
498 rc
= fill_stats_for_pid(pid
, stats
);
501 return send_reply(rep_skb
, info
);
507 static int cmd_attr_tgid(struct genl_info
*info
)
509 struct taskstats
*stats
;
510 struct sk_buff
*rep_skb
;
515 size
= taskstats_packet_size();
517 rc
= prepare_reply(info
, TASKSTATS_CMD_NEW
, &rep_skb
, size
);
522 tgid
= nla_get_u32(info
->attrs
[TASKSTATS_CMD_ATTR_TGID
]);
523 stats
= mk_reply(rep_skb
, TASKSTATS_TYPE_TGID
, tgid
);
527 rc
= fill_stats_for_tgid(tgid
, stats
);
530 return send_reply(rep_skb
, info
);
536 static int taskstats_user_cmd(struct sk_buff
*skb
, struct genl_info
*info
)
538 if (info
->attrs
[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK
])
539 return cmd_attr_register_cpumask(info
);
540 else if (info
->attrs
[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK
])
541 return cmd_attr_deregister_cpumask(info
);
542 else if (info
->attrs
[TASKSTATS_CMD_ATTR_PID
])
543 return cmd_attr_pid(info
);
544 else if (info
->attrs
[TASKSTATS_CMD_ATTR_TGID
])
545 return cmd_attr_tgid(info
);
550 static struct taskstats
*taskstats_tgid_alloc(struct task_struct
*tsk
)
552 struct signal_struct
*sig
= tsk
->signal
;
553 struct taskstats
*stats_new
, *stats
;
555 /* Pairs with smp_store_release() below. */
556 stats
= smp_load_acquire(&sig
->stats
);
557 if (stats
|| thread_group_empty(tsk
))
560 /* No problem if kmem_cache_zalloc() fails */
561 stats_new
= kmem_cache_zalloc(taskstats_cache
, GFP_KERNEL
);
563 spin_lock_irq(&tsk
->sighand
->siglock
);
567 * Pairs with smp_store_release() above and order the
568 * kmem_cache_zalloc().
570 smp_store_release(&sig
->stats
, stats_new
);
574 spin_unlock_irq(&tsk
->sighand
->siglock
);
577 kmem_cache_free(taskstats_cache
, stats_new
);
582 /* Send pid data out on exit */
583 void taskstats_exit(struct task_struct
*tsk
, int group_dead
)
586 struct listener_list
*listeners
;
587 struct taskstats
*stats
;
588 struct sk_buff
*rep_skb
;
592 if (!family_registered
)
596 * Size includes space for nested attributes
598 size
= taskstats_packet_size();
600 is_thread_group
= !!taskstats_tgid_alloc(tsk
);
601 if (is_thread_group
) {
602 /* PID + STATS + TGID + STATS */
604 /* fill the tsk->signal->stats structure */
608 listeners
= raw_cpu_ptr(&listener_array
);
609 if (list_empty(&listeners
->list
))
612 rc
= prepare_reply(NULL
, TASKSTATS_CMD_NEW
, &rep_skb
, size
);
616 stats
= mk_reply(rep_skb
, TASKSTATS_TYPE_PID
,
617 task_pid_nr_ns(tsk
, &init_pid_ns
));
621 fill_stats(&init_user_ns
, &init_pid_ns
, tsk
, stats
);
624 * Doesn't matter if tsk is the leader or the last group member leaving
626 if (!is_thread_group
|| !group_dead
)
629 stats
= mk_reply(rep_skb
, TASKSTATS_TYPE_TGID
,
630 task_tgid_nr_ns(tsk
, &init_pid_ns
));
634 memcpy(stats
, tsk
->signal
->stats
, sizeof(*stats
));
637 send_cpu_listeners(rep_skb
, listeners
);
643 static const struct genl_ops taskstats_ops
[] = {
645 .cmd
= TASKSTATS_CMD_GET
,
646 .validate
= GENL_DONT_VALIDATE_STRICT
| GENL_DONT_VALIDATE_DUMP
,
647 .doit
= taskstats_user_cmd
,
648 .policy
= taskstats_cmd_get_policy
,
649 .maxattr
= ARRAY_SIZE(taskstats_cmd_get_policy
) - 1,
650 .flags
= GENL_ADMIN_PERM
,
653 .cmd
= CGROUPSTATS_CMD_GET
,
654 .validate
= GENL_DONT_VALIDATE_STRICT
| GENL_DONT_VALIDATE_DUMP
,
655 .doit
= cgroupstats_user_cmd
,
656 .policy
= cgroupstats_cmd_get_policy
,
657 .maxattr
= ARRAY_SIZE(cgroupstats_cmd_get_policy
) - 1,
661 static struct genl_family family __ro_after_init
= {
662 .name
= TASKSTATS_GENL_NAME
,
663 .version
= TASKSTATS_GENL_VERSION
,
664 .module
= THIS_MODULE
,
665 .ops
= taskstats_ops
,
666 .n_ops
= ARRAY_SIZE(taskstats_ops
),
669 /* Needed early in initialization */
670 void __init
taskstats_init_early(void)
674 taskstats_cache
= KMEM_CACHE(taskstats
, SLAB_PANIC
);
675 for_each_possible_cpu(i
) {
676 INIT_LIST_HEAD(&(per_cpu(listener_array
, i
).list
));
677 init_rwsem(&(per_cpu(listener_array
, i
).sem
));
681 static int __init
taskstats_init(void)
685 rc
= genl_register_family(&family
);
689 family_registered
= 1;
690 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION
);
695 * late initcall ensures initialization of statistics collection
696 * mechanisms precedes initialization of the taskstats interface
698 late_initcall(taskstats_init
);