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/* delayacct.c - per-task delay accounting
  2 *
  3 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
  4 *
  5 * This program is free software;  you can redistribute it and/or modify
  6 * it under the terms of the GNU General Public License as published by
  7 * the Free Software Foundation; either version 2 of the License, or
  8 * (at your option) any later version.
  9 *
 10 * This program is distributed in the hope that it would be useful, but
 11 * WITHOUT ANY WARRANTY; without even the implied warranty of
 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 13 * the GNU General Public License for more details.
 14 */
 15
 16#include <linux/sched.h>
 17#include <linux/sched/task.h>
 18#include <linux/sched/cputime.h>
 19#include <linux/slab.h>
 20#include <linux/taskstats.h>
 21#include <linux/time.h>
 22#include <linux/sysctl.h>
 23#include <linux/delayacct.h>
 24#include <linux/module.h>
 25
 26int delayacct_on __read_mostly = 1;	/* Delay accounting turned on/off */
 27EXPORT_SYMBOL_GPL(delayacct_on);
 28struct kmem_cache *delayacct_cache;
 29
 30static int __init delayacct_setup_disable(char *str)
 31{
 32	delayacct_on = 0;
 33	return 1;
 34}
 35__setup("nodelayacct", delayacct_setup_disable);
 36
 37void delayacct_init(void)
 38{
 39	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
 40	delayacct_tsk_init(&init_task);
 41}
 42
 43void __delayacct_tsk_init(struct task_struct *tsk)
 44{
 45	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
 46	if (tsk->delays)
 47		spin_lock_init(&tsk->delays->lock);
 48}
 49
 50/*
 51 * Finish delay accounting for a statistic using its timestamps (@start),
 52 * accumalator (@total) and @count
 53 */
 54static void delayacct_end(spinlock_t *lock, u64 *start, u64 *total, u32 *count)
 
 55{
 56	s64 ns = ktime_get_ns() - *start;
 57	unsigned long flags;
 58
 59	if (ns > 0) {
 60		spin_lock_irqsave(lock, flags);
 61		*total += ns;
 62		(*count)++;
 63		spin_unlock_irqrestore(lock, flags);
 64	}
 65}
 66
 67void __delayacct_blkio_start(void)
 68{
 69	current->delays->blkio_start = ktime_get_ns();
 70}
 71
 72/*
 73 * We cannot rely on the `current` macro, as we haven't yet switched back to
 74 * the process being woken.
 75 */
 76void __delayacct_blkio_end(struct task_struct *p)
 77{
 78	struct task_delay_info *delays = p->delays;
 79	u64 *total;
 80	u32 *count;
 81
 82	if (p->delays->flags & DELAYACCT_PF_SWAPIN) {
 83		total = &delays->swapin_delay;
 84		count = &delays->swapin_count;
 85	} else {
 86		total = &delays->blkio_delay;
 87		count = &delays->blkio_count;
 88	}
 89
 90	delayacct_end(&delays->lock, &delays->blkio_start, total, count);
 91}
 92
 93int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
 94{
 95	u64 utime, stime, stimescaled, utimescaled;
 96	unsigned long long t2, t3;
 97	unsigned long flags, t1;
 98	s64 tmp;
 99
100	task_cputime(tsk, &utime, &stime);
101	tmp = (s64)d->cpu_run_real_total;
102	tmp += utime + stime;
103	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
104
105	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
106	tmp = (s64)d->cpu_scaled_run_real_total;
107	tmp += utimescaled + stimescaled;
108	d->cpu_scaled_run_real_total =
109		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
110
111	/*
112	 * No locking available for sched_info (and too expensive to add one)
113	 * Mitigate by taking snapshot of values
114	 */
115	t1 = tsk->sched_info.pcount;
116	t2 = tsk->sched_info.run_delay;
117	t3 = tsk->se.sum_exec_runtime;
118
119	d->cpu_count += t1;
120
121	tmp = (s64)d->cpu_delay_total + t2;
122	d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
123
124	tmp = (s64)d->cpu_run_virtual_total + t3;
125	d->cpu_run_virtual_total =
126		(tmp < (s64)d->cpu_run_virtual_total) ?	0 : tmp;
127
128	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
129
130	spin_lock_irqsave(&tsk->delays->lock, flags);
131	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
132	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
133	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
134	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
135	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
136	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
 
 
137	d->blkio_count += tsk->delays->blkio_count;
138	d->swapin_count += tsk->delays->swapin_count;
139	d->freepages_count += tsk->delays->freepages_count;
140	spin_unlock_irqrestore(&tsk->delays->lock, flags);
 
141
142	return 0;
143}
144
145__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
146{
147	__u64 ret;
148	unsigned long flags;
149
150	spin_lock_irqsave(&tsk->delays->lock, flags);
151	ret = nsec_to_clock_t(tsk->delays->blkio_delay +
152				tsk->delays->swapin_delay);
153	spin_unlock_irqrestore(&tsk->delays->lock, flags);
154	return ret;
155}
156
157void __delayacct_freepages_start(void)
158{
159	current->delays->freepages_start = ktime_get_ns();
160}
161
162void __delayacct_freepages_end(void)
163{
164	delayacct_end(
165		&current->delays->lock,
166		&current->delays->freepages_start,
167		&current->delays->freepages_delay,
168		&current->delays->freepages_count);
169}
170