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/slab.h>
 18#include <linux/taskstats.h>
 19#include <linux/time.h>
 20#include <linux/sysctl.h>
 21#include <linux/delayacct.h>
 22#include <linux/module.h>
 23
 24int delayacct_on __read_mostly = 1;	/* Delay accounting turned on/off */
 25EXPORT_SYMBOL_GPL(delayacct_on);
 26struct kmem_cache *delayacct_cache;
 27
 28static int __init delayacct_setup_disable(char *str)
 29{
 30	delayacct_on = 0;
 31	return 1;
 32}
 33__setup("nodelayacct", delayacct_setup_disable);
 34
 35void delayacct_init(void)
 36{
 37	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
 38	delayacct_tsk_init(&init_task);
 39}
 40
 41void __delayacct_tsk_init(struct task_struct *tsk)
 42{
 43	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
 44	if (tsk->delays)
 45		spin_lock_init(&tsk->delays->lock);
 46}
 47
 48/*
 49 * Finish delay accounting for a statistic using its timestamps (@start),
 50 * accumalator (@total) and @count
 51 */
 52static void delayacct_end(u64 *start, u64 *total, u32 *count)
 
 
 
 
 
 
 
 
 
 
 
 
 53{
 54	s64 ns = ktime_get_ns() - *start;
 
 55	unsigned long flags;
 56
 57	if (ns > 0) {
 58		spin_lock_irqsave(&current->delays->lock, flags);
 59		*total += ns;
 60		(*count)++;
 61		spin_unlock_irqrestore(&current->delays->lock, flags);
 62	}
 
 
 
 
 63}
 64
 65void __delayacct_blkio_start(void)
 66{
 67	current->delays->blkio_start = ktime_get_ns();
 68}
 69
 70void __delayacct_blkio_end(void)
 71{
 72	if (current->delays->flags & DELAYACCT_PF_SWAPIN)
 73		/* Swapin block I/O */
 74		delayacct_end(&current->delays->blkio_start,
 
 75			&current->delays->swapin_delay,
 76			&current->delays->swapin_count);
 77	else	/* Other block I/O */
 78		delayacct_end(&current->delays->blkio_start,
 
 79			&current->delays->blkio_delay,
 80			&current->delays->blkio_count);
 81}
 82
 83int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
 84{
 85	cputime_t utime, stime, stimescaled, utimescaled;
 86	unsigned long long t2, t3;
 87	unsigned long flags, t1;
 88	s64 tmp;
 
 
 
 
 
 
 
 
 
 
 89
 90	task_cputime(tsk, &utime, &stime);
 91	tmp = (s64)d->cpu_run_real_total;
 92	tmp += cputime_to_nsecs(utime + stime);
 
 93	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
 94
 95	task_cputime_scaled(tsk, &utimescaled, &stimescaled);
 96	tmp = (s64)d->cpu_scaled_run_real_total;
 97	tmp += cputime_to_nsecs(utimescaled + stimescaled);
 
 98	d->cpu_scaled_run_real_total =
 99		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
100
101	/*
102	 * No locking available for sched_info (and too expensive to add one)
103	 * Mitigate by taking snapshot of values
104	 */
105	t1 = tsk->sched_info.pcount;
106	t2 = tsk->sched_info.run_delay;
107	t3 = tsk->se.sum_exec_runtime;
108
109	d->cpu_count += t1;
110
111	tmp = (s64)d->cpu_delay_total + t2;
112	d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
113
114	tmp = (s64)d->cpu_run_virtual_total + t3;
115	d->cpu_run_virtual_total =
116		(tmp < (s64)d->cpu_run_virtual_total) ?	0 : tmp;
117
118	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
119
120	spin_lock_irqsave(&tsk->delays->lock, flags);
121	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
122	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
123	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
124	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
125	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
126	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
127	d->blkio_count += tsk->delays->blkio_count;
128	d->swapin_count += tsk->delays->swapin_count;
129	d->freepages_count += tsk->delays->freepages_count;
130	spin_unlock_irqrestore(&tsk->delays->lock, flags);
131
 
132	return 0;
133}
134
135__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
136{
137	__u64 ret;
138	unsigned long flags;
139
140	spin_lock_irqsave(&tsk->delays->lock, flags);
141	ret = nsec_to_clock_t(tsk->delays->blkio_delay +
142				tsk->delays->swapin_delay);
143	spin_unlock_irqrestore(&tsk->delays->lock, flags);
144	return ret;
145}
146
147void __delayacct_freepages_start(void)
148{
149	current->delays->freepages_start = ktime_get_ns();
150}
151
152void __delayacct_freepages_end(void)
153{
154	delayacct_end(&current->delays->freepages_start,
 
155			&current->delays->freepages_delay,
156			&current->delays->freepages_count);
157}
158

  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/slab.h>
 18#include <linux/taskstats.h>
 19#include <linux/time.h>
 20#include <linux/sysctl.h>
 21#include <linux/delayacct.h>
 22#include <linux/module.h>
 23
 24int delayacct_on __read_mostly = 1;	/* Delay accounting turned on/off */
 25EXPORT_SYMBOL_GPL(delayacct_on);
 26struct kmem_cache *delayacct_cache;
 27
 28static int __init delayacct_setup_disable(char *str)
 29{
 30	delayacct_on = 0;
 31	return 1;
 32}
 33__setup("nodelayacct", delayacct_setup_disable);
 34
 35void delayacct_init(void)
 36{
 37	delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC);
 38	delayacct_tsk_init(&init_task);
 39}
 40
 41void __delayacct_tsk_init(struct task_struct *tsk)
 42{
 43	tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
 44	if (tsk->delays)
 45		spin_lock_init(&tsk->delays->lock);
 46}
 47
 48/*
 49 * Start accounting for a delay statistic using
 50 * its starting timestamp (@start)
 51 */
 52
 53static inline void delayacct_start(struct timespec *start)
 54{
 55	do_posix_clock_monotonic_gettime(start);
 56}
 57
 58/*
 59 * Finish delay accounting for a statistic using
 60 * its timestamps (@start, @end), accumalator (@total) and @count
 61 */
 62
 63static void delayacct_end(struct timespec *start, struct timespec *end,
 64				u64 *total, u32 *count)
 65{
 66	struct timespec ts;
 67	s64 ns;
 68	unsigned long flags;
 69
 70	do_posix_clock_monotonic_gettime(end);
 71	ts = timespec_sub(*end, *start);
 72	ns = timespec_to_ns(&ts);
 73	if (ns < 0)
 74		return;
 75
 76	spin_lock_irqsave(&current->delays->lock, flags);
 77	*total += ns;
 78	(*count)++;
 79	spin_unlock_irqrestore(&current->delays->lock, flags);
 80}
 81
 82void __delayacct_blkio_start(void)
 83{
 84	delayacct_start(&current->delays->blkio_start);
 85}
 86
 87void __delayacct_blkio_end(void)
 88{
 89	if (current->delays->flags & DELAYACCT_PF_SWAPIN)
 90		/* Swapin block I/O */
 91		delayacct_end(&current->delays->blkio_start,
 92			&current->delays->blkio_end,
 93			&current->delays->swapin_delay,
 94			&current->delays->swapin_count);
 95	else	/* Other block I/O */
 96		delayacct_end(&current->delays->blkio_start,
 97			&current->delays->blkio_end,
 98			&current->delays->blkio_delay,
 99			&current->delays->blkio_count);
100}
101
102int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
103{
 
 
 
104	s64 tmp;
105	unsigned long t1;
106	unsigned long long t2, t3;
107	unsigned long flags;
108	struct timespec ts;
109
110	/* Though tsk->delays accessed later, early exit avoids
111	 * unnecessary returning of other data
112	 */
113	if (!tsk->delays)
114		goto done;
115
 
116	tmp = (s64)d->cpu_run_real_total;
117	cputime_to_timespec(tsk->utime + tsk->stime, &ts);
118	tmp += timespec_to_ns(&ts);
119	d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
120
 
121	tmp = (s64)d->cpu_scaled_run_real_total;
122	cputime_to_timespec(tsk->utimescaled + tsk->stimescaled, &ts);
123	tmp += timespec_to_ns(&ts);
124	d->cpu_scaled_run_real_total =
125		(tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
126
127	/*
128	 * No locking available for sched_info (and too expensive to add one)
129	 * Mitigate by taking snapshot of values
130	 */
131	t1 = tsk->sched_info.pcount;
132	t2 = tsk->sched_info.run_delay;
133	t3 = tsk->se.sum_exec_runtime;
134
135	d->cpu_count += t1;
136
137	tmp = (s64)d->cpu_delay_total + t2;
138	d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
139
140	tmp = (s64)d->cpu_run_virtual_total + t3;
141	d->cpu_run_virtual_total =
142		(tmp < (s64)d->cpu_run_virtual_total) ?	0 : tmp;
143
144	/* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
145
146	spin_lock_irqsave(&tsk->delays->lock, flags);
147	tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
148	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
149	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
150	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
151	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
152	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
153	d->blkio_count += tsk->delays->blkio_count;
154	d->swapin_count += tsk->delays->swapin_count;
155	d->freepages_count += tsk->delays->freepages_count;
156	spin_unlock_irqrestore(&tsk->delays->lock, flags);
157
158done:
159	return 0;
160}
161
162__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
163{
164	__u64 ret;
165	unsigned long flags;
166
167	spin_lock_irqsave(&tsk->delays->lock, flags);
168	ret = nsec_to_clock_t(tsk->delays->blkio_delay +
169				tsk->delays->swapin_delay);
170	spin_unlock_irqrestore(&tsk->delays->lock, flags);
171	return ret;
172}
173
174void __delayacct_freepages_start(void)
175{
176	delayacct_start(&current->delays->freepages_start);
177}
178
179void __delayacct_freepages_end(void)
180{
181	delayacct_end(&current->delays->freepages_start,
182			&current->delays->freepages_end,
183			&current->delays->freepages_delay,
184			&current->delays->freepages_count);
185}
186