1 /* delayacct.c - per-task delay accounting
3 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
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.
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.
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>
24 int delayacct_on __read_mostly
= 1; /* Delay accounting turned on/off */
25 EXPORT_SYMBOL_GPL(delayacct_on
);
26 struct kmem_cache
*delayacct_cache
;
28 static int __init
delayacct_setup_disable(char *str
)
33 __setup("nodelayacct", delayacct_setup_disable
);
35 void delayacct_init(void)
37 delayacct_cache
= KMEM_CACHE(task_delay_info
, SLAB_PANIC
);
38 delayacct_tsk_init(&init_task
);
41 void __delayacct_tsk_init(struct task_struct
*tsk
)
43 tsk
->delays
= kmem_cache_zalloc(delayacct_cache
, GFP_KERNEL
);
45 spin_lock_init(&tsk
->delays
->lock
);
49 * Finish delay accounting for a statistic using
50 * its timestamps (@start, @end), accumalator (@total) and @count
53 static void delayacct_end(struct timespec
*start
, struct timespec
*end
,
54 u64
*total
, u32
*count
)
61 ts
= timespec_sub(*end
, *start
);
62 ns
= timespec_to_ns(&ts
);
66 spin_lock_irqsave(¤t
->delays
->lock
, flags
);
69 spin_unlock_irqrestore(¤t
->delays
->lock
, flags
);
72 void __delayacct_blkio_start(void)
74 ktime_get_ts(¤t
->delays
->blkio_start
);
77 void __delayacct_blkio_end(void)
79 if (current
->delays
->flags
& DELAYACCT_PF_SWAPIN
)
80 /* Swapin block I/O */
81 delayacct_end(¤t
->delays
->blkio_start
,
82 ¤t
->delays
->blkio_end
,
83 ¤t
->delays
->swapin_delay
,
84 ¤t
->delays
->swapin_count
);
85 else /* Other block I/O */
86 delayacct_end(¤t
->delays
->blkio_start
,
87 ¤t
->delays
->blkio_end
,
88 ¤t
->delays
->blkio_delay
,
89 ¤t
->delays
->blkio_count
);
92 int __delayacct_add_tsk(struct taskstats
*d
, struct task_struct
*tsk
)
96 unsigned long long t2
, t3
;
99 cputime_t utime
, stime
, stimescaled
, utimescaled
;
101 tmp
= (s64
)d
->cpu_run_real_total
;
102 task_cputime(tsk
, &utime
, &stime
);
103 cputime_to_timespec(utime
+ stime
, &ts
);
104 tmp
+= timespec_to_ns(&ts
);
105 d
->cpu_run_real_total
= (tmp
< (s64
)d
->cpu_run_real_total
) ? 0 : tmp
;
107 tmp
= (s64
)d
->cpu_scaled_run_real_total
;
108 task_cputime_scaled(tsk
, &utimescaled
, &stimescaled
);
109 cputime_to_timespec(utimescaled
+ stimescaled
, &ts
);
110 tmp
+= timespec_to_ns(&ts
);
111 d
->cpu_scaled_run_real_total
=
112 (tmp
< (s64
)d
->cpu_scaled_run_real_total
) ? 0 : tmp
;
115 * No locking available for sched_info (and too expensive to add one)
116 * Mitigate by taking snapshot of values
118 t1
= tsk
->sched_info
.pcount
;
119 t2
= tsk
->sched_info
.run_delay
;
120 t3
= tsk
->se
.sum_exec_runtime
;
124 tmp
= (s64
)d
->cpu_delay_total
+ t2
;
125 d
->cpu_delay_total
= (tmp
< (s64
)d
->cpu_delay_total
) ? 0 : tmp
;
127 tmp
= (s64
)d
->cpu_run_virtual_total
+ t3
;
128 d
->cpu_run_virtual_total
=
129 (tmp
< (s64
)d
->cpu_run_virtual_total
) ? 0 : tmp
;
131 /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
133 spin_lock_irqsave(&tsk
->delays
->lock
, flags
);
134 tmp
= d
->blkio_delay_total
+ tsk
->delays
->blkio_delay
;
135 d
->blkio_delay_total
= (tmp
< d
->blkio_delay_total
) ? 0 : tmp
;
136 tmp
= d
->swapin_delay_total
+ tsk
->delays
->swapin_delay
;
137 d
->swapin_delay_total
= (tmp
< d
->swapin_delay_total
) ? 0 : tmp
;
138 tmp
= d
->freepages_delay_total
+ tsk
->delays
->freepages_delay
;
139 d
->freepages_delay_total
= (tmp
< d
->freepages_delay_total
) ? 0 : tmp
;
140 d
->blkio_count
+= tsk
->delays
->blkio_count
;
141 d
->swapin_count
+= tsk
->delays
->swapin_count
;
142 d
->freepages_count
+= tsk
->delays
->freepages_count
;
143 spin_unlock_irqrestore(&tsk
->delays
->lock
, flags
);
148 __u64
__delayacct_blkio_ticks(struct task_struct
*tsk
)
153 spin_lock_irqsave(&tsk
->delays
->lock
, flags
);
154 ret
= nsec_to_clock_t(tsk
->delays
->blkio_delay
+
155 tsk
->delays
->swapin_delay
);
156 spin_unlock_irqrestore(&tsk
->delays
->lock
, flags
);
160 void __delayacct_freepages_start(void)
162 ktime_get_ts(¤t
->delays
->freepages_start
);
165 void __delayacct_freepages_end(void)
167 delayacct_end(¤t
->delays
->freepages_start
,
168 ¤t
->delays
->freepages_end
,
169 ¤t
->delays
->freepages_delay
,
170 ¤t
->delays
->freepages_count
);