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1
2#ifdef CONFIG_SCHEDSTATS
3/*
4 * bump this up when changing the output format or the meaning of an existing
5 * format, so that tools can adapt (or abort)
6 */
7#define SCHEDSTAT_VERSION 15
8
9static int show_schedstat(struct seq_file *seq, void *v)
10{
11 int cpu;
12 int mask_len = DIV_ROUND_UP(NR_CPUS, 32) * 9;
13 char *mask_str = kmalloc(mask_len, GFP_KERNEL);
14
15 if (mask_str == NULL)
16 return -ENOMEM;
17
18 seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
19 seq_printf(seq, "timestamp %lu\n", jiffies);
20 for_each_online_cpu(cpu) {
21 struct rq *rq = cpu_rq(cpu);
22#ifdef CONFIG_SMP
23 struct sched_domain *sd;
24 int dcount = 0;
25#endif
26
27 /* runqueue-specific stats */
28 seq_printf(seq,
29 "cpu%d %u %u %u %u %u %u %llu %llu %lu",
30 cpu, rq->yld_count,
31 rq->sched_switch, rq->sched_count, rq->sched_goidle,
32 rq->ttwu_count, rq->ttwu_local,
33 rq->rq_cpu_time,
34 rq->rq_sched_info.run_delay, rq->rq_sched_info.pcount);
35
36 seq_printf(seq, "\n");
37
38#ifdef CONFIG_SMP
39 /* domain-specific stats */
40 rcu_read_lock();
41 for_each_domain(cpu, sd) {
42 enum cpu_idle_type itype;
43
44 cpumask_scnprintf(mask_str, mask_len,
45 sched_domain_span(sd));
46 seq_printf(seq, "domain%d %s", dcount++, mask_str);
47 for (itype = CPU_IDLE; itype < CPU_MAX_IDLE_TYPES;
48 itype++) {
49 seq_printf(seq, " %u %u %u %u %u %u %u %u",
50 sd->lb_count[itype],
51 sd->lb_balanced[itype],
52 sd->lb_failed[itype],
53 sd->lb_imbalance[itype],
54 sd->lb_gained[itype],
55 sd->lb_hot_gained[itype],
56 sd->lb_nobusyq[itype],
57 sd->lb_nobusyg[itype]);
58 }
59 seq_printf(seq,
60 " %u %u %u %u %u %u %u %u %u %u %u %u\n",
61 sd->alb_count, sd->alb_failed, sd->alb_pushed,
62 sd->sbe_count, sd->sbe_balanced, sd->sbe_pushed,
63 sd->sbf_count, sd->sbf_balanced, sd->sbf_pushed,
64 sd->ttwu_wake_remote, sd->ttwu_move_affine,
65 sd->ttwu_move_balance);
66 }
67 rcu_read_unlock();
68#endif
69 }
70 kfree(mask_str);
71 return 0;
72}
73
74static int schedstat_open(struct inode *inode, struct file *file)
75{
76 unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
77 char *buf = kmalloc(size, GFP_KERNEL);
78 struct seq_file *m;
79 int res;
80
81 if (!buf)
82 return -ENOMEM;
83 res = single_open(file, show_schedstat, NULL);
84 if (!res) {
85 m = file->private_data;
86 m->buf = buf;
87 m->size = size;
88 } else
89 kfree(buf);
90 return res;
91}
92
93static const struct file_operations proc_schedstat_operations = {
94 .open = schedstat_open,
95 .read = seq_read,
96 .llseek = seq_lseek,
97 .release = single_release,
98};
99
100static int __init proc_schedstat_init(void)
101{
102 proc_create("schedstat", 0, NULL, &proc_schedstat_operations);
103 return 0;
104}
105module_init(proc_schedstat_init);
106
107/*
108 * Expects runqueue lock to be held for atomicity of update
109 */
110static inline void
111rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
112{
113 if (rq) {
114 rq->rq_sched_info.run_delay += delta;
115 rq->rq_sched_info.pcount++;
116 }
117}
118
119/*
120 * Expects runqueue lock to be held for atomicity of update
121 */
122static inline void
123rq_sched_info_depart(struct rq *rq, unsigned long long delta)
124{
125 if (rq)
126 rq->rq_cpu_time += delta;
127}
128
129static inline void
130rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
131{
132 if (rq)
133 rq->rq_sched_info.run_delay += delta;
134}
135# define schedstat_inc(rq, field) do { (rq)->field++; } while (0)
136# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0)
137# define schedstat_set(var, val) do { var = (val); } while (0)
138#else /* !CONFIG_SCHEDSTATS */
139static inline void
140rq_sched_info_arrive(struct rq *rq, unsigned long long delta)
141{}
142static inline void
143rq_sched_info_dequeued(struct rq *rq, unsigned long long delta)
144{}
145static inline void
146rq_sched_info_depart(struct rq *rq, unsigned long long delta)
147{}
148# define schedstat_inc(rq, field) do { } while (0)
149# define schedstat_add(rq, field, amt) do { } while (0)
150# define schedstat_set(var, val) do { } while (0)
151#endif
152
153#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
154static inline void sched_info_reset_dequeued(struct task_struct *t)
155{
156 t->sched_info.last_queued = 0;
157}
158
159/*
160 * We are interested in knowing how long it was from the *first* time a
161 * task was queued to the time that it finally hit a cpu, we call this routine
162 * from dequeue_task() to account for possible rq->clock skew across cpus. The
163 * delta taken on each cpu would annul the skew.
164 */
165static inline void sched_info_dequeued(struct task_struct *t)
166{
167 unsigned long long now = task_rq(t)->clock, delta = 0;
168
169 if (unlikely(sched_info_on()))
170 if (t->sched_info.last_queued)
171 delta = now - t->sched_info.last_queued;
172 sched_info_reset_dequeued(t);
173 t->sched_info.run_delay += delta;
174
175 rq_sched_info_dequeued(task_rq(t), delta);
176}
177
178/*
179 * Called when a task finally hits the cpu. We can now calculate how
180 * long it was waiting to run. We also note when it began so that we
181 * can keep stats on how long its timeslice is.
182 */
183static void sched_info_arrive(struct task_struct *t)
184{
185 unsigned long long now = task_rq(t)->clock, delta = 0;
186
187 if (t->sched_info.last_queued)
188 delta = now - t->sched_info.last_queued;
189 sched_info_reset_dequeued(t);
190 t->sched_info.run_delay += delta;
191 t->sched_info.last_arrival = now;
192 t->sched_info.pcount++;
193
194 rq_sched_info_arrive(task_rq(t), delta);
195}
196
197/*
198 * This function is only called from enqueue_task(), but also only updates
199 * the timestamp if it is already not set. It's assumed that
200 * sched_info_dequeued() will clear that stamp when appropriate.
201 */
202static inline void sched_info_queued(struct task_struct *t)
203{
204 if (unlikely(sched_info_on()))
205 if (!t->sched_info.last_queued)
206 t->sched_info.last_queued = task_rq(t)->clock;
207}
208
209/*
210 * Called when a process ceases being the active-running process, either
211 * voluntarily or involuntarily. Now we can calculate how long we ran.
212 * Also, if the process is still in the TASK_RUNNING state, call
213 * sched_info_queued() to mark that it has now again started waiting on
214 * the runqueue.
215 */
216static inline void sched_info_depart(struct task_struct *t)
217{
218 unsigned long long delta = task_rq(t)->clock -
219 t->sched_info.last_arrival;
220
221 rq_sched_info_depart(task_rq(t), delta);
222
223 if (t->state == TASK_RUNNING)
224 sched_info_queued(t);
225}
226
227/*
228 * Called when tasks are switched involuntarily due, typically, to expiring
229 * their time slice. (This may also be called when switching to or from
230 * the idle task.) We are only called when prev != next.
231 */
232static inline void
233__sched_info_switch(struct task_struct *prev, struct task_struct *next)
234{
235 struct rq *rq = task_rq(prev);
236
237 /*
238 * prev now departs the cpu. It's not interesting to record
239 * stats about how efficient we were at scheduling the idle
240 * process, however.
241 */
242 if (prev != rq->idle)
243 sched_info_depart(prev);
244
245 if (next != rq->idle)
246 sched_info_arrive(next);
247}
248static inline void
249sched_info_switch(struct task_struct *prev, struct task_struct *next)
250{
251 if (unlikely(sched_info_on()))
252 __sched_info_switch(prev, next);
253}
254#else
255#define sched_info_queued(t) do { } while (0)
256#define sched_info_reset_dequeued(t) do { } while (0)
257#define sched_info_dequeued(t) do { } while (0)
258#define sched_info_switch(t, next) do { } while (0)
259#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
260
261/*
262 * The following are functions that support scheduler-internal time accounting.
263 * These functions are generally called at the timer tick. None of this depends
264 * on CONFIG_SCHEDSTATS.
265 */
266
267/**
268 * account_group_user_time - Maintain utime for a thread group.
269 *
270 * @tsk: Pointer to task structure.
271 * @cputime: Time value by which to increment the utime field of the
272 * thread_group_cputime structure.
273 *
274 * If thread group time is being maintained, get the structure for the
275 * running CPU and update the utime field there.
276 */
277static inline void account_group_user_time(struct task_struct *tsk,
278 cputime_t cputime)
279{
280 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
281
282 if (!cputimer->running)
283 return;
284
285 spin_lock(&cputimer->lock);
286 cputimer->cputime.utime =
287 cputime_add(cputimer->cputime.utime, cputime);
288 spin_unlock(&cputimer->lock);
289}
290
291/**
292 * account_group_system_time - Maintain stime for a thread group.
293 *
294 * @tsk: Pointer to task structure.
295 * @cputime: Time value by which to increment the stime field of the
296 * thread_group_cputime structure.
297 *
298 * If thread group time is being maintained, get the structure for the
299 * running CPU and update the stime field there.
300 */
301static inline void account_group_system_time(struct task_struct *tsk,
302 cputime_t cputime)
303{
304 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
305
306 if (!cputimer->running)
307 return;
308
309 spin_lock(&cputimer->lock);
310 cputimer->cputime.stime =
311 cputime_add(cputimer->cputime.stime, cputime);
312 spin_unlock(&cputimer->lock);
313}
314
315/**
316 * account_group_exec_runtime - Maintain exec runtime for a thread group.
317 *
318 * @tsk: Pointer to task structure.
319 * @ns: Time value by which to increment the sum_exec_runtime field
320 * of the thread_group_cputime structure.
321 *
322 * If thread group time is being maintained, get the structure for the
323 * running CPU and update the sum_exec_runtime field there.
324 */
325static inline void account_group_exec_runtime(struct task_struct *tsk,
326 unsigned long long ns)
327{
328 struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
329
330 if (!cputimer->running)
331 return;
332
333 spin_lock(&cputimer->lock);
334 cputimer->cputime.sum_exec_runtime += ns;
335 spin_unlock(&cputimer->lock);
336}