media: tegra: Tegra videobuf2
[linux-2.6.git] / kernel / delayacct.c
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  * Start accounting for a delay statistic using
50  * its starting timestamp (@start)
51  */
52
53 static 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
63 static 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
82 void __delayacct_blkio_start(void)
83 {
84         delayacct_start(&current->delays->blkio_start);
85 }
86
87 void __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
102 int __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
158 done:
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
174 void __delayacct_freepages_start(void)
175 {
176         delayacct_start(&current->delays->freepages_start);
177 }
178
179 void __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