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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); |
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 | |
159 |
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