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Source at commit ec7cab4cbb721bff91ec924ec691efd8daf36579 created 12 years 8 months ago. By Maarten ter Huurne, MIPS: JZ4740: A320: Updated quickstart documentation. | |
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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 | |
23 | int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */ |
24 | struct kmem_cache *delayacct_cache; |
25 | |
26 | static int __init delayacct_setup_disable(char *str) |
27 | { |
28 | delayacct_on = 0; |
29 | return 1; |
30 | } |
31 | __setup("nodelayacct", delayacct_setup_disable); |
32 | |
33 | void delayacct_init(void) |
34 | { |
35 | delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC); |
36 | delayacct_tsk_init(&init_task); |
37 | } |
38 | |
39 | void __delayacct_tsk_init(struct task_struct *tsk) |
40 | { |
41 | tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL); |
42 | if (tsk->delays) |
43 | spin_lock_init(&tsk->delays->lock); |
44 | } |
45 | |
46 | /* |
47 | * Start accounting for a delay statistic using |
48 | * its starting timestamp (@start) |
49 | */ |
50 | |
51 | static inline void delayacct_start(struct timespec *start) |
52 | { |
53 | do_posix_clock_monotonic_gettime(start); |
54 | } |
55 | |
56 | /* |
57 | * Finish delay accounting for a statistic using |
58 | * its timestamps (@start, @end), accumalator (@total) and @count |
59 | */ |
60 | |
61 | static void delayacct_end(struct timespec *start, struct timespec *end, |
62 | u64 *total, u32 *count) |
63 | { |
64 | struct timespec ts; |
65 | s64 ns; |
66 | unsigned long flags; |
67 | |
68 | do_posix_clock_monotonic_gettime(end); |
69 | ts = timespec_sub(*end, *start); |
70 | ns = timespec_to_ns(&ts); |
71 | if (ns < 0) |
72 | return; |
73 | |
74 | spin_lock_irqsave(¤t->delays->lock, flags); |
75 | *total += ns; |
76 | (*count)++; |
77 | spin_unlock_irqrestore(¤t->delays->lock, flags); |
78 | } |
79 | |
80 | void __delayacct_blkio_start(void) |
81 | { |
82 | delayacct_start(¤t->delays->blkio_start); |
83 | } |
84 | |
85 | void __delayacct_blkio_end(void) |
86 | { |
87 | if (current->delays->flags & DELAYACCT_PF_SWAPIN) |
88 | /* Swapin block I/O */ |
89 | delayacct_end(¤t->delays->blkio_start, |
90 | ¤t->delays->blkio_end, |
91 | ¤t->delays->swapin_delay, |
92 | ¤t->delays->swapin_count); |
93 | else /* Other block I/O */ |
94 | delayacct_end(¤t->delays->blkio_start, |
95 | ¤t->delays->blkio_end, |
96 | ¤t->delays->blkio_delay, |
97 | ¤t->delays->blkio_count); |
98 | } |
99 | |
100 | int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) |
101 | { |
102 | s64 tmp; |
103 | unsigned long t1; |
104 | unsigned long long t2, t3; |
105 | unsigned long flags; |
106 | struct timespec ts; |
107 | |
108 | /* Though tsk->delays accessed later, early exit avoids |
109 | * unnecessary returning of other data |
110 | */ |
111 | if (!tsk->delays) |
112 | goto done; |
113 | |
114 | tmp = (s64)d->cpu_run_real_total; |
115 | cputime_to_timespec(tsk->utime + tsk->stime, &ts); |
116 | tmp += timespec_to_ns(&ts); |
117 | d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp; |
118 | |
119 | tmp = (s64)d->cpu_scaled_run_real_total; |
120 | cputime_to_timespec(tsk->utimescaled + tsk->stimescaled, &ts); |
121 | tmp += timespec_to_ns(&ts); |
122 | d->cpu_scaled_run_real_total = |
123 | (tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp; |
124 | |
125 | /* |
126 | * No locking available for sched_info (and too expensive to add one) |
127 | * Mitigate by taking snapshot of values |
128 | */ |
129 | t1 = tsk->sched_info.pcount; |
130 | t2 = tsk->sched_info.run_delay; |
131 | t3 = tsk->se.sum_exec_runtime; |
132 | |
133 | d->cpu_count += t1; |
134 | |
135 | tmp = (s64)d->cpu_delay_total + t2; |
136 | d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp; |
137 | |
138 | tmp = (s64)d->cpu_run_virtual_total + t3; |
139 | d->cpu_run_virtual_total = |
140 | (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp; |
141 | |
142 | /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ |
143 | |
144 | spin_lock_irqsave(&tsk->delays->lock, flags); |
145 | tmp = d->blkio_delay_total + tsk->delays->blkio_delay; |
146 | d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; |
147 | tmp = d->swapin_delay_total + tsk->delays->swapin_delay; |
148 | d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp; |
149 | tmp = d->freepages_delay_total + tsk->delays->freepages_delay; |
150 | d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp; |
151 | d->blkio_count += tsk->delays->blkio_count; |
152 | d->swapin_count += tsk->delays->swapin_count; |
153 | d->freepages_count += tsk->delays->freepages_count; |
154 | spin_unlock_irqrestore(&tsk->delays->lock, flags); |
155 | |
156 | done: |
157 | return 0; |
158 | } |
159 | |
160 | __u64 __delayacct_blkio_ticks(struct task_struct *tsk) |
161 | { |
162 | __u64 ret; |
163 | unsigned long flags; |
164 | |
165 | spin_lock_irqsave(&tsk->delays->lock, flags); |
166 | ret = nsec_to_clock_t(tsk->delays->blkio_delay + |
167 | tsk->delays->swapin_delay); |
168 | spin_unlock_irqrestore(&tsk->delays->lock, flags); |
169 | return ret; |
170 | } |
171 | |
172 | void __delayacct_freepages_start(void) |
173 | { |
174 | delayacct_start(¤t->delays->freepages_start); |
175 | } |
176 | |
177 | void __delayacct_freepages_end(void) |
178 | { |
179 | delayacct_end(¤t->delays->freepages_start, |
180 | ¤t->delays->freepages_end, |
181 | ¤t->delays->freepages_delay, |
182 | ¤t->delays->freepages_count); |
183 | } |
184 | |
185 |
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