ia64/linux-2.6.18-xen.hg

view kernel/delayacct.c @ 562:66faefe721eb

pvSCSI backend driver

Signed-off-by: Tomonari Horikoshi <t.horikoshi@jp.fujitsu.com>
Signed-off-by: Jun Kamada <kama@jp.fujitsu.com>
author Keir Fraser <keir.fraser@citrix.com>
date Mon Jun 02 09:58:27 2008 +0100 (2008-06-02)
parents 831230e53067
children
line source
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 */
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/time.h>
19 #include <linux/sysctl.h>
20 #include <linux/delayacct.h>
22 int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */
23 kmem_cache_t *delayacct_cache;
25 static int __init delayacct_setup_disable(char *str)
26 {
27 delayacct_on = 0;
28 return 1;
29 }
30 __setup("nodelayacct", delayacct_setup_disable);
32 void delayacct_init(void)
33 {
34 delayacct_cache = kmem_cache_create("delayacct_cache",
35 sizeof(struct task_delay_info),
36 0,
37 SLAB_PANIC,
38 NULL, NULL);
39 delayacct_tsk_init(&init_task);
40 }
42 void __delayacct_tsk_init(struct task_struct *tsk)
43 {
44 tsk->delays = kmem_cache_zalloc(delayacct_cache, SLAB_KERNEL);
45 if (tsk->delays)
46 spin_lock_init(&tsk->delays->lock);
47 }
49 /*
50 * Start accounting for a delay statistic using
51 * its starting timestamp (@start)
52 */
54 static inline void delayacct_start(struct timespec *start)
55 {
56 do_posix_clock_monotonic_gettime(start);
57 }
59 /*
60 * Finish delay accounting for a statistic using
61 * its timestamps (@start, @end), accumalator (@total) and @count
62 */
64 static void delayacct_end(struct timespec *start, struct timespec *end,
65 u64 *total, u32 *count)
66 {
67 struct timespec ts;
68 s64 ns;
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;
76 spin_lock(&current->delays->lock);
77 *total += ns;
78 (*count)++;
79 spin_unlock(&current->delays->lock);
80 }
82 void __delayacct_blkio_start(void)
83 {
84 delayacct_start(&current->delays->blkio_start);
85 }
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 }
102 int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
103 {
104 s64 tmp;
105 struct timespec ts;
106 unsigned long t1,t2,t3;
108 /* Though tsk->delays accessed later, early exit avoids
109 * unnecessary returning of other data
110 */
111 if (!tsk->delays)
112 goto done;
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;
119 /*
120 * No locking available for sched_info (and too expensive to add one)
121 * Mitigate by taking snapshot of values
122 */
123 t1 = tsk->sched_info.pcnt;
124 t2 = tsk->sched_info.run_delay;
125 t3 = tsk->sched_info.cpu_time;
127 d->cpu_count += t1;
129 jiffies_to_timespec(t2, &ts);
130 tmp = (s64)d->cpu_delay_total + timespec_to_ns(&ts);
131 d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
133 tmp = (s64)d->cpu_run_virtual_total + (s64)jiffies_to_usecs(t3) * 1000;
134 d->cpu_run_virtual_total =
135 (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp;
137 /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
139 spin_lock(&tsk->delays->lock);
140 tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
141 d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
142 tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
143 d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
144 d->blkio_count += tsk->delays->blkio_count;
145 d->swapin_count += tsk->delays->swapin_count;
146 spin_unlock(&tsk->delays->lock);
148 done:
149 return 0;
150 }
152 __u64 __delayacct_blkio_ticks(struct task_struct *tsk)
153 {
154 __u64 ret;
156 spin_lock(&tsk->delays->lock);
157 ret = nsec_to_clock_t(tsk->delays->blkio_delay +
158 tsk->delays->swapin_delay);
159 spin_unlock(&tsk->delays->lock);
160 return ret;
161 }