1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* delayacct.c - per-task delay accounting
  3 *
  4 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
  5 */
  6
  7#include <linux/sched.h>
  8#include <linux/sched/task.h>
  9#include <linux/sched/cputime.h>
 
 10#include <linux/slab.h>
 11#include <linux/taskstats.h>
 12#include <linux/time.h>
 13#include <linux/sysctl.h>
 14#include <linux/delayacct.h>
 15#include <linux/module.h>
 16
 17int delayacct_on __read_mostly = 1;	/* Delay accounting turned on/off */
 18EXPORT_SYMBOL_GPL(delayacct_on);
 19struct kmem_cache *delayacct_cache;
 20
 21static int __init delayacct_setup_disable(char *str)
 22{
 23	delayacct_on = 0;
 
 
 
 
 
 
 
 
 
 
 
 24	return 1;
 25}
 26__setup("nodelayacct", delayacct_setup_disable);
 27
 28void delayacct_init(void)
 29{
 30	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
 31	delayacct_tsk_init(&init_task);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 32}
 
 
 33
 34void __delayacct_tsk_init(struct task_struct *tsk)
 35{
 36	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
 37	if (tsk->delays)
 38		raw_spin_lock_init(&tsk->delays->lock);
 39}
 40
 41/*
 42 * Finish delay accounting for a statistic using its timestamps (@start),
 43 * accumalator (@total) and @count
 44 */
 45static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total,
 46			  u32 *count)
 47{
 48	s64 ns = ktime_get_ns() - *start;
 49	unsigned long flags;
 50
 51	if (ns > 0) {
 52		raw_spin_lock_irqsave(lock, flags);
 53		*total += ns;
 54		(*count)++;
 55		raw_spin_unlock_irqrestore(lock, flags);
 56	}
 57}
 58
 59void __delayacct_blkio_start(void)
 60{
 61	current->delays->blkio_start = ktime_get_ns();
 62}
 63
 64/*
 65 * We cannot rely on the `current` macro, as we haven't yet switched back to
 66 * the process being woken.
 67 */
 68void __delayacct_blkio_end(struct task_struct *p)
 69{
 70	struct task_delay_info *delays = p->delays;
 71	u64 *total;
 72	u32 *count;
 73
 74	if (p->delays->flags & DELAYACCT_PF_SWAPIN) {
 75		total = &delays->swapin_delay;
 76		count = &delays->swapin_count;
 77	} else {
 78		total = &delays->blkio_delay;
 79		count = &delays->blkio_count;
 80	}
 81
 82	delayacct_end(&delays->lock, &delays->blkio_start, total, count);
 83}
 84
 85int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
 86{
 87	u64 utime, stime, stimescaled, utimescaled;
 88	unsigned long long t2, t3;
 89	unsigned long flags, t1;
 90	s64 tmp;
 91
 92	task_cputime(tsk, &utime, &stime);
 93	tmp = (s64)d->cpu_run_real_total;
 94	tmp += utime + stime;
 95	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
 96
 97	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
 98	tmp = (s64)d->cpu_scaled_run_real_total;
 99	tmp += utimescaled + stimescaled;
100	d->cpu_scaled_run_real_total =
101		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
102
103	/*
104	 * No locking available for sched_info (and too expensive to add one)
105	 * Mitigate by taking snapshot of values
106	 */
107	t1 = tsk->sched_info.pcount;
108	t2 = tsk->sched_info.run_delay;
109	t3 = tsk->se.sum_exec_runtime;
110
111	d->cpu_count += t1;
112
113	tmp = (s64)d->cpu_delay_total + t2;
114	d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
115
116	tmp = (s64)d->cpu_run_virtual_total + t3;
117	d->cpu_run_virtual_total =
118		(tmp < (s64)d->cpu_run_virtual_total) ?	0 : tmp;
119
 
 
 
120	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
121
122	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
123	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
124	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
125	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
126	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
127	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
128	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
129	tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
130	d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
 
 
 
 
131	d->blkio_count += tsk->delays->blkio_count;
132	d->swapin_count += tsk->delays->swapin_count;
133	d->freepages_count += tsk->delays->freepages_count;
134	d->thrashing_count += tsk->delays->thrashing_count;
 
 
135	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
136
137	return 0;
138}
139
140__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
141{
142	__u64 ret;
143	unsigned long flags;
144
145	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
146	ret = nsec_to_clock_t(tsk->delays->blkio_delay +
147				tsk->delays->swapin_delay);
148	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
149	return ret;
150}
151
152void __delayacct_freepages_start(void)
153{
154	current->delays->freepages_start = ktime_get_ns();
155}
156
157void __delayacct_freepages_end(void)
158{
159	delayacct_end(
160		&current->delays->lock,
161		&current->delays->freepages_start,
162		&current->delays->freepages_delay,
163		&current->delays->freepages_count);
164}
165
166void __delayacct_thrashing_start(void)
167{
168	current->delays->thrashing_start = ktime_get_ns();
 
 
 
 
 
169}
170
171void __delayacct_thrashing_end(void)
172{
 
 
 
 
173	delayacct_end(&current->delays->lock,
174		      &current->delays->thrashing_start,
175		      &current->delays->thrashing_delay,
176		      &current->delays->thrashing_count);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
177}

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* delayacct.c - per-task delay accounting
  3 *
  4 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
  5 */
  6
  7#include <linux/sched.h>
  8#include <linux/sched/task.h>
  9#include <linux/sched/cputime.h>
 10#include <linux/sched/clock.h>
 11#include <linux/slab.h>
 12#include <linux/taskstats.h>
 
 13#include <linux/sysctl.h>
 14#include <linux/delayacct.h>
 15#include <linux/module.h>
 16
 17DEFINE_STATIC_KEY_FALSE(delayacct_key);
 18int delayacct_on __read_mostly;	/* Delay accounting turned on/off */
 19struct kmem_cache *delayacct_cache;
 20
 21static void set_delayacct(bool enabled)
 22{
 23	if (enabled) {
 24		static_branch_enable(&delayacct_key);
 25		delayacct_on = 1;
 26	} else {
 27		delayacct_on = 0;
 28		static_branch_disable(&delayacct_key);
 29	}
 30}
 31
 32static int __init delayacct_setup_enable(char *str)
 33{
 34	delayacct_on = 1;
 35	return 1;
 36}
 37__setup("delayacct", delayacct_setup_enable);
 38
 39void delayacct_init(void)
 40{
 41	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
 42	delayacct_tsk_init(&init_task);
 43	set_delayacct(delayacct_on);
 44}
 45
 46#ifdef CONFIG_PROC_SYSCTL
 47static int sysctl_delayacct(struct ctl_table *table, int write, void *buffer,
 48		     size_t *lenp, loff_t *ppos)
 49{
 50	int state = delayacct_on;
 51	struct ctl_table t;
 52	int err;
 53
 54	if (write && !capable(CAP_SYS_ADMIN))
 55		return -EPERM;
 56
 57	t = *table;
 58	t.data = &state;
 59	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
 60	if (err < 0)
 61		return err;
 62	if (write)
 63		set_delayacct(state);
 64	return err;
 65}
 66
 67static struct ctl_table kern_delayacct_table[] = {
 68	{
 69		.procname       = "task_delayacct",
 70		.data           = NULL,
 71		.maxlen         = sizeof(unsigned int),
 72		.mode           = 0644,
 73		.proc_handler   = sysctl_delayacct,
 74		.extra1         = SYSCTL_ZERO,
 75		.extra2         = SYSCTL_ONE,
 76	},
 77	{ }
 78};
 79
 80static __init int kernel_delayacct_sysctls_init(void)
 81{
 82	register_sysctl_init("kernel", kern_delayacct_table);
 83	return 0;
 84}
 85late_initcall(kernel_delayacct_sysctls_init);
 86#endif
 87
 88void __delayacct_tsk_init(struct task_struct *tsk)
 89{
 90	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
 91	if (tsk->delays)
 92		raw_spin_lock_init(&tsk->delays->lock);
 93}
 94
 95/*
 96 * Finish delay accounting for a statistic using its timestamps (@start),
 97 * accumalator (@total) and @count
 98 */
 99static void delayacct_end(raw_spinlock_t *lock, u64 *start, u64 *total, u32 *count)
 
100{
101	s64 ns = local_clock() - *start;
102	unsigned long flags;
103
104	if (ns > 0) {
105		raw_spin_lock_irqsave(lock, flags);
106		*total += ns;
107		(*count)++;
108		raw_spin_unlock_irqrestore(lock, flags);
109	}
110}
111
112void __delayacct_blkio_start(void)
113{
114	current->delays->blkio_start = local_clock();
115}
116
117/*
118 * We cannot rely on the `current` macro, as we haven't yet switched back to
119 * the process being woken.
120 */
121void __delayacct_blkio_end(struct task_struct *p)
122{
123	delayacct_end(&p->delays->lock,
124		      &p->delays->blkio_start,
125		      &p->delays->blkio_delay,
126		      &p->delays->blkio_count);
 
 
 
 
 
 
 
 
 
127}
128
129int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
130{
131	u64 utime, stime, stimescaled, utimescaled;
132	unsigned long long t2, t3;
133	unsigned long flags, t1;
134	s64 tmp;
135
136	task_cputime(tsk, &utime, &stime);
137	tmp = (s64)d->cpu_run_real_total;
138	tmp += utime + stime;
139	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
140
141	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
142	tmp = (s64)d->cpu_scaled_run_real_total;
143	tmp += utimescaled + stimescaled;
144	d->cpu_scaled_run_real_total =
145		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
146
147	/*
148	 * No locking available for sched_info (and too expensive to add one)
149	 * Mitigate by taking snapshot of values
150	 */
151	t1 = tsk->sched_info.pcount;
152	t2 = tsk->sched_info.run_delay;
153	t3 = tsk->se.sum_exec_runtime;
154
155	d->cpu_count += t1;
156
157	tmp = (s64)d->cpu_delay_total + t2;
158	d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
159
160	tmp = (s64)d->cpu_run_virtual_total + t3;
161	d->cpu_run_virtual_total =
162		(tmp < (s64)d->cpu_run_virtual_total) ?	0 : tmp;
163
164	if (!tsk->delays)
165		return 0;
166
167	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
168
169	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
170	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
171	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
172	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
173	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
174	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
175	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
176	tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
177	d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
178	tmp = d->compact_delay_total + tsk->delays->compact_delay;
179	d->compact_delay_total = (tmp < d->compact_delay_total) ? 0 : tmp;
180	tmp = d->wpcopy_delay_total + tsk->delays->wpcopy_delay;
181	d->wpcopy_delay_total = (tmp < d->wpcopy_delay_total) ? 0 : tmp;
182	d->blkio_count += tsk->delays->blkio_count;
183	d->swapin_count += tsk->delays->swapin_count;
184	d->freepages_count += tsk->delays->freepages_count;
185	d->thrashing_count += tsk->delays->thrashing_count;
186	d->compact_count += tsk->delays->compact_count;
187	d->wpcopy_count += tsk->delays->wpcopy_count;
188	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
189
190	return 0;
191}
192
193__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
194{
195	__u64 ret;
196	unsigned long flags;
197
198	raw_spin_lock_irqsave(&tsk->delays->lock, flags);
199	ret = nsec_to_clock_t(tsk->delays->blkio_delay);
 
200	raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
201	return ret;
202}
203
204void __delayacct_freepages_start(void)
205{
206	current->delays->freepages_start = local_clock();
207}
208
209void __delayacct_freepages_end(void)
210{
211	delayacct_end(&current->delays->lock,
212		      &current->delays->freepages_start,
213		      &current->delays->freepages_delay,
214		      &current->delays->freepages_count);
 
215}
216
217void __delayacct_thrashing_start(bool *in_thrashing)
218{
219	*in_thrashing = !!current->in_thrashing;
220	if (*in_thrashing)
221		return;
222
223	current->in_thrashing = 1;
224	current->delays->thrashing_start = local_clock();
225}
226
227void __delayacct_thrashing_end(bool *in_thrashing)
228{
229	if (*in_thrashing)
230		return;
231
232	current->in_thrashing = 0;
233	delayacct_end(&current->delays->lock,
234		      &current->delays->thrashing_start,
235		      &current->delays->thrashing_delay,
236		      &current->delays->thrashing_count);
237}
238
239void __delayacct_swapin_start(void)
240{
241	current->delays->swapin_start = local_clock();
242}
243
244void __delayacct_swapin_end(void)
245{
246	delayacct_end(&current->delays->lock,
247		      &current->delays->swapin_start,
248		      &current->delays->swapin_delay,
249		      &current->delays->swapin_count);
250}
251
252void __delayacct_compact_start(void)
253{
254	current->delays->compact_start = local_clock();
255}
256
257void __delayacct_compact_end(void)
258{
259	delayacct_end(&current->delays->lock,
260		      &current->delays->compact_start,
261		      &current->delays->compact_delay,
262		      &current->delays->compact_count);
263}
264
265void __delayacct_wpcopy_start(void)
266{
267	current->delays->wpcopy_start = local_clock();
268}
269
270void __delayacct_wpcopy_end(void)
271{
272	delayacct_end(&current->delays->lock,
273		      &current->delays->wpcopy_start,
274		      &current->delays->wpcopy_delay,
275		      &current->delays->wpcopy_count);
276}