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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> | |
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 | ||
24 | int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */ | |
25 | EXPORT_SYMBOL_GPL(delayacct_on); | |
26 | struct kmem_cache *delayacct_cache; | |
27 | ||
28 | static int __init delayacct_setup_disable(char *str) | |
29 | { | |
30 | delayacct_on = 0; | |
31 | return 1; | |
32 | } | |
33 | __setup("nodelayacct", delayacct_setup_disable); | |
34 | ||
35 | void delayacct_init(void) | |
36 | { | |
37 | delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT); | |
38 | delayacct_tsk_init(&init_task); | |
39 | } | |
40 | ||
41 | void __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 | */ | |
52 | static 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(¤t->delays->lock, flags); | |
59 | *total += ns; | |
60 | (*count)++; | |
61 | spin_unlock_irqrestore(¤t->delays->lock, flags); | |
62 | } | |
63 | } | |
64 | ||
65 | void __delayacct_blkio_start(void) | |
66 | { | |
67 | current->delays->blkio_start = ktime_get_ns(); | |
68 | } | |
69 | ||
70 | void __delayacct_blkio_end(void) | |
71 | { | |
72 | if (current->delays->flags & DELAYACCT_PF_SWAPIN) | |
73 | /* Swapin block I/O */ | |
74 | delayacct_end(¤t->delays->blkio_start, | |
75 | ¤t->delays->swapin_delay, | |
76 | ¤t->delays->swapin_count); | |
77 | else /* Other block I/O */ | |
78 | delayacct_end(¤t->delays->blkio_start, | |
79 | ¤t->delays->blkio_delay, | |
80 | ¤t->delays->blkio_count); | |
81 | } | |
82 | ||
83 | int __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 | ||
147 | void __delayacct_freepages_start(void) | |
148 | { | |
149 | current->delays->freepages_start = ktime_get_ns(); | |
150 | } | |
151 | ||
152 | void __delayacct_freepages_end(void) | |
153 | { | |
154 | delayacct_end(¤t->delays->freepages_start, | |
155 | ¤t->delays->freepages_delay, | |
156 | ¤t->delays->freepages_count); | |
157 | } | |
158 |