cputime.h

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