xref: /linux/include/linux/sched/cputime.h (revision 71e2f4dd5a65bd8dbca0b77661e75eea471168f8)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SCHED_CPUTIME_H
3 #define _LINUX_SCHED_CPUTIME_H
4 
5 #include <linux/sched/signal.h>
6 
7 /*
8  * cputime accounting APIs:
9  */
10 
11 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
12 #include <asm/cputime.h>
13 
14 #ifndef cputime_to_nsecs
15 # define cputime_to_nsecs(__ct)	\
16 	(cputime_to_usecs(__ct) * NSEC_PER_USEC)
17 #endif
18 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
19 
20 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
21 extern void task_cputime(struct task_struct *t,
22 			 u64 *utime, u64 *stime);
23 extern u64 task_gtime(struct task_struct *t);
24 #else
25 static inline void task_cputime(struct task_struct *t,
26 				u64 *utime, u64 *stime)
27 {
28 	*utime = t->utime;
29 	*stime = t->stime;
30 }
31 
32 static inline u64 task_gtime(struct task_struct *t)
33 {
34 	return t->gtime;
35 }
36 #endif
37 
38 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
39 static inline void task_cputime_scaled(struct task_struct *t,
40 				       u64 *utimescaled,
41 				       u64 *stimescaled)
42 {
43 	*utimescaled = t->utimescaled;
44 	*stimescaled = t->stimescaled;
45 }
46 #else
47 static inline void task_cputime_scaled(struct task_struct *t,
48 				       u64 *utimescaled,
49 				       u64 *stimescaled)
50 {
51 	task_cputime(t, utimescaled, stimescaled);
52 }
53 #endif
54 
55 extern void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st);
56 extern void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st);
57 extern void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
58 			   u64 *ut, u64 *st);
59 
60 /*
61  * Thread group CPU time accounting.
62  */
63 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times);
64 void thread_group_sample_cputime(struct task_struct *tsk, u64 *samples);
65 
66 /*
67  * The following are functions that support scheduler-internal time accounting.
68  * These functions are generally called at the timer tick.  None of this depends
69  * on CONFIG_SCHEDSTATS.
70  */
71 
72 /**
73  * get_running_cputimer - return &tsk->signal->cputimer if cputimers are active
74  *
75  * @tsk:	Pointer to target task.
76  */
77 #ifdef CONFIG_POSIX_TIMERS
78 static inline
79 struct thread_group_cputimer *get_running_cputimer(struct task_struct *tsk)
80 {
81 	struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
82 
83 	/*
84 	 * Check whether posix CPU timers are active. If not the thread
85 	 * group accounting is not active either. Lockless check.
86 	 */
87 	if (!READ_ONCE(tsk->signal->posix_cputimers.timers_active))
88 		return NULL;
89 
90 	/*
91 	 * After we flush the task's sum_exec_runtime to sig->sum_sched_runtime
92 	 * in __exit_signal(), we won't account to the signal struct further
93 	 * cputime consumed by that task, even though the task can still be
94 	 * ticking after __exit_signal().
95 	 *
96 	 * In order to keep a consistent behaviour between thread group cputime
97 	 * and thread group cputimer accounting, lets also ignore the cputime
98 	 * elapsing after __exit_signal() in any thread group timer running.
99 	 *
100 	 * This makes sure that POSIX CPU clocks and timers are synchronized, so
101 	 * that a POSIX CPU timer won't expire while the corresponding POSIX CPU
102 	 * clock delta is behind the expiring timer value.
103 	 */
104 	if (unlikely(!tsk->sighand))
105 		return NULL;
106 
107 	return cputimer;
108 }
109 #else
110 static inline
111 struct thread_group_cputimer *get_running_cputimer(struct task_struct *tsk)
112 {
113 	return NULL;
114 }
115 #endif
116 
117 /**
118  * account_group_user_time - Maintain utime for a thread group.
119  *
120  * @tsk:	Pointer to task structure.
121  * @cputime:	Time value by which to increment the utime field of the
122  *		thread_group_cputime structure.
123  *
124  * If thread group time is being maintained, get the structure for the
125  * running CPU and update the utime field there.
126  */
127 static inline void account_group_user_time(struct task_struct *tsk,
128 					   u64 cputime)
129 {
130 	struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
131 
132 	if (!cputimer)
133 		return;
134 
135 	atomic64_add(cputime, &cputimer->cputime_atomic.utime);
136 }
137 
138 /**
139  * account_group_system_time - Maintain stime for a thread group.
140  *
141  * @tsk:	Pointer to task structure.
142  * @cputime:	Time value by which to increment the stime field of the
143  *		thread_group_cputime structure.
144  *
145  * If thread group time is being maintained, get the structure for the
146  * running CPU and update the stime field there.
147  */
148 static inline void account_group_system_time(struct task_struct *tsk,
149 					     u64 cputime)
150 {
151 	struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
152 
153 	if (!cputimer)
154 		return;
155 
156 	atomic64_add(cputime, &cputimer->cputime_atomic.stime);
157 }
158 
159 /**
160  * account_group_exec_runtime - Maintain exec runtime for a thread group.
161  *
162  * @tsk:	Pointer to task structure.
163  * @ns:		Time value by which to increment the sum_exec_runtime field
164  *		of the thread_group_cputime structure.
165  *
166  * If thread group time is being maintained, get the structure for the
167  * running CPU and update the sum_exec_runtime field there.
168  */
169 static inline void account_group_exec_runtime(struct task_struct *tsk,
170 					      unsigned long long ns)
171 {
172 	struct thread_group_cputimer *cputimer = get_running_cputimer(tsk);
173 
174 	if (!cputimer)
175 		return;
176 
177 	atomic64_add(ns, &cputimer->cputime_atomic.sum_exec_runtime);
178 }
179 
180 static inline void prev_cputime_init(struct prev_cputime *prev)
181 {
182 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
183 	prev->utime = prev->stime = 0;
184 	raw_spin_lock_init(&prev->lock);
185 #endif
186 }
187 
188 extern unsigned long long
189 task_sched_runtime(struct task_struct *task);
190 
191 #endif /* _LINUX_SCHED_CPUTIME_H */
192