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ca74e92b
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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>
9164bb4a 17#include <linux/sched/task.h>
32ef5517 18#include <linux/sched/cputime.h>
ca74e92b 19#include <linux/slab.h>
6952b61d 20#include <linux/taskstats.h>
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21#include <linux/time.h>
22#include <linux/sysctl.h>
23#include <linux/delayacct.h>
c9aaa895 24#include <linux/module.h>
ca74e92b 25
163ecdff 26int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */
c9aaa895 27EXPORT_SYMBOL_GPL(delayacct_on);
e18b890b 28struct kmem_cache *delayacct_cache;
ca74e92b 29
163ecdff 30static int __init delayacct_setup_disable(char *str)
ca74e92b 31{
163ecdff 32 delayacct_on = 0;
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33 return 1;
34}
163ecdff 35__setup("nodelayacct", delayacct_setup_disable);
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36
37void delayacct_init(void)
38{
5d097056 39 delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT);
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40 delayacct_tsk_init(&init_task);
41}
42
43void __delayacct_tsk_init(struct task_struct *tsk)
44{
e94b1766 45 tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
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46 if (tsk->delays)
47 spin_lock_init(&tsk->delays->lock);
48}
49
ca74e92b 50/*
9667a23d
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51 * Finish delay accounting for a statistic using its timestamps (@start),
52 * accumalator (@total) and @count
ca74e92b 53 */
9667a23d 54static void delayacct_end(u64 *start, u64 *total, u32 *count)
ca74e92b 55{
9667a23d 56 s64 ns = ktime_get_ns() - *start;
64efade1 57 unsigned long flags;
ca74e92b 58
9667a23d
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59 if (ns > 0) {
60 spin_lock_irqsave(&current->delays->lock, flags);
61 *total += ns;
62 (*count)++;
63 spin_unlock_irqrestore(&current->delays->lock, flags);
64 }
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65}
66
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67void __delayacct_blkio_start(void)
68{
9667a23d 69 current->delays->blkio_start = ktime_get_ns();
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70}
71
72void __delayacct_blkio_end(void)
73{
74 if (current->delays->flags & DELAYACCT_PF_SWAPIN)
75 /* Swapin block I/O */
76 delayacct_end(&current->delays->blkio_start,
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77 &current->delays->swapin_delay,
78 &current->delays->swapin_count);
79 else /* Other block I/O */
80 delayacct_end(&current->delays->blkio_start,
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81 &current->delays->blkio_delay,
82 &current->delays->blkio_count);
83}
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84
85int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
86{
dbf3da1c 87 u64 utime, stime, stimescaled, utimescaled;
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88 unsigned long long t2, t3;
89 unsigned long flags, t1;
90 s64 tmp;
6f44993f 91
dbf3da1c 92 task_cputime(tsk, &utime, &stime);
68f6783d 93 tmp = (s64)d->cpu_run_real_total;
dbf3da1c 94 tmp += utime + stime;
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95 d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
96
dbf3da1c 97 task_cputime_scaled(tsk, &utimescaled, &stimescaled);
68f6783d 98 tmp = (s64)d->cpu_scaled_run_real_total;
dbf3da1c 99 tmp += utimescaled + stimescaled;
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100 d->cpu_scaled_run_real_total =
101 (tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
102
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103 /*
104 * No locking available for sched_info (and too expensive to add one)
105 * Mitigate by taking snapshot of values
106 */
2d72376b 107 t1 = tsk->sched_info.pcount;
6f44993f 108 t2 = tsk->sched_info.run_delay;
9c2c4802 109 t3 = tsk->se.sum_exec_runtime;
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110
111 d->cpu_count += t1;
112
172ba844 113 tmp = (s64)d->cpu_delay_total + t2;
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114 d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
115
172ba844 116 tmp = (s64)d->cpu_run_virtual_total + t3;
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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
64efade1 122 spin_lock_irqsave(&tsk->delays->lock, flags);
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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;
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127 tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
128 d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
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129 d->blkio_count += tsk->delays->blkio_count;
130 d->swapin_count += tsk->delays->swapin_count;
016ae219 131 d->freepages_count += tsk->delays->freepages_count;
64efade1 132 spin_unlock_irqrestore(&tsk->delays->lock, flags);
6f44993f 133
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134 return 0;
135}
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136
137__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
138{
139 __u64 ret;
64efade1 140 unsigned long flags;
25890454 141
64efade1 142 spin_lock_irqsave(&tsk->delays->lock, flags);
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143 ret = nsec_to_clock_t(tsk->delays->blkio_delay +
144 tsk->delays->swapin_delay);
64efade1 145 spin_unlock_irqrestore(&tsk->delays->lock, flags);
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146 return ret;
147}
148
873b4771
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149void __delayacct_freepages_start(void)
150{
9667a23d 151 current->delays->freepages_start = ktime_get_ns();
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152}
153
154void __delayacct_freepages_end(void)
155{
156 delayacct_end(&current->delays->freepages_start,
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157 &current->delays->freepages_delay,
158 &current->delays->freepages_count);
159}
160