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Shailabh Nagarca74e922006-07-14 00:24:36 -07001/* 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>
Alexey Dobriyan6952b612009-09-18 23:55:55 +040018#include <linux/taskstats.h>
Shailabh Nagarca74e922006-07-14 00:24:36 -070019#include <linux/time.h>
20#include <linux/sysctl.h>
21#include <linux/delayacct.h>
Glauber Costac9aaa892011-07-11 15:28:14 -040022#include <linux/module.h>
Shailabh Nagarca74e922006-07-14 00:24:36 -070023
Shailabh Nagar163ecdf2006-07-30 03:03:11 -070024int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */
Glauber Costac9aaa892011-07-11 15:28:14 -040025EXPORT_SYMBOL_GPL(delayacct_on);
Christoph Lametere18b8902006-12-06 20:33:20 -080026struct kmem_cache *delayacct_cache;
Shailabh Nagarca74e922006-07-14 00:24:36 -070027
Shailabh Nagar163ecdf2006-07-30 03:03:11 -070028static int __init delayacct_setup_disable(char *str)
Shailabh Nagarca74e922006-07-14 00:24:36 -070029{
Shailabh Nagar163ecdf2006-07-30 03:03:11 -070030 delayacct_on = 0;
Shailabh Nagarca74e922006-07-14 00:24:36 -070031 return 1;
32}
Shailabh Nagar163ecdf2006-07-30 03:03:11 -070033__setup("nodelayacct", delayacct_setup_disable);
Shailabh Nagarca74e922006-07-14 00:24:36 -070034
35void delayacct_init(void)
36{
Christoph Lameter0a31bd52007-05-06 14:49:57 -070037 delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC);
Shailabh Nagarca74e922006-07-14 00:24:36 -070038 delayacct_tsk_init(&init_task);
39}
40
41void __delayacct_tsk_init(struct task_struct *tsk)
42{
Christoph Lametere94b1762006-12-06 20:33:17 -080043 tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
Shailabh Nagarca74e922006-07-14 00:24:36 -070044 if (tsk->delays)
45 spin_lock_init(&tsk->delays->lock);
46}
47
Shailabh Nagarca74e922006-07-14 00:24:36 -070048/*
49 * Start accounting for a delay statistic using
50 * its starting timestamp (@start)
51 */
52
53static 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
63static void delayacct_end(struct timespec *start, struct timespec *end,
64 u64 *total, u32 *count)
65{
66 struct timespec ts;
67 s64 ns;
Peter Zijlstra64efade2006-11-05 23:52:10 -080068 unsigned long flags;
Shailabh Nagarca74e922006-07-14 00:24:36 -070069
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
Peter Zijlstra64efade2006-11-05 23:52:10 -080076 spin_lock_irqsave(&current->delays->lock, flags);
Shailabh Nagarca74e922006-07-14 00:24:36 -070077 *total += ns;
78 (*count)++;
Peter Zijlstra64efade2006-11-05 23:52:10 -080079 spin_unlock_irqrestore(&current->delays->lock, flags);
Shailabh Nagarca74e922006-07-14 00:24:36 -070080}
81
Shailabh Nagar0ff92242006-07-14 00:24:37 -070082void __delayacct_blkio_start(void)
83{
84 delayacct_start(&current->delays->blkio_start);
85}
86
87void __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}
Shailabh Nagar6f449932006-07-14 00:24:41 -0700101
102int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
103{
104 s64 tmp;
Balbir Singh172ba842007-07-09 18:52:00 +0200105 unsigned long t1;
106 unsigned long long t2, t3;
Peter Zijlstra64efade2006-11-05 23:52:10 -0800107 unsigned long flags;
Balbir Singh172ba842007-07-09 18:52:00 +0200108 struct timespec ts;
Frederic Weisbecker6fac4822012-11-13 14:20:55 +0100109 cputime_t utime, stime, stimescaled, utimescaled;
Shailabh Nagar6f449932006-07-14 00:24:41 -0700110
Shailabh Nagar6f449932006-07-14 00:24:41 -0700111 tmp = (s64)d->cpu_run_real_total;
Frederic Weisbecker6fac4822012-11-13 14:20:55 +0100112 task_cputime(tsk, &utime, &stime);
113 cputime_to_timespec(utime + stime, &ts);
Shailabh Nagar6f449932006-07-14 00:24:41 -0700114 tmp += timespec_to_ns(&ts);
115 d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
116
Michael Neulingc66f08b2007-10-18 03:06:34 -0700117 tmp = (s64)d->cpu_scaled_run_real_total;
Frederic Weisbecker6fac4822012-11-13 14:20:55 +0100118 task_cputime_scaled(tsk, &utimescaled, &stimescaled);
119 cputime_to_timespec(utimescaled + stimescaled, &ts);
Michael Neulingc66f08b2007-10-18 03:06:34 -0700120 tmp += timespec_to_ns(&ts);
121 d->cpu_scaled_run_real_total =
122 (tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
123
Shailabh Nagar6f449932006-07-14 00:24:41 -0700124 /*
125 * No locking available for sched_info (and too expensive to add one)
126 * Mitigate by taking snapshot of values
127 */
Ingo Molnar2d723762007-10-15 17:00:12 +0200128 t1 = tsk->sched_info.pcount;
Shailabh Nagar6f449932006-07-14 00:24:41 -0700129 t2 = tsk->sched_info.run_delay;
Ken Chen9c2c4802008-12-16 23:41:22 -0800130 t3 = tsk->se.sum_exec_runtime;
Shailabh Nagar6f449932006-07-14 00:24:41 -0700131
132 d->cpu_count += t1;
133
Balbir Singh172ba842007-07-09 18:52:00 +0200134 tmp = (s64)d->cpu_delay_total + t2;
Shailabh Nagar6f449932006-07-14 00:24:41 -0700135 d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
136
Balbir Singh172ba842007-07-09 18:52:00 +0200137 tmp = (s64)d->cpu_run_virtual_total + t3;
Shailabh Nagar6f449932006-07-14 00:24:41 -0700138 d->cpu_run_virtual_total =
139 (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp;
140
141 /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
142
Peter Zijlstra64efade2006-11-05 23:52:10 -0800143 spin_lock_irqsave(&tsk->delays->lock, flags);
Shailabh Nagar6f449932006-07-14 00:24:41 -0700144 tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
145 d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
146 tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
147 d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
Keika Kobayashi016ae212008-07-25 01:48:53 -0700148 tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
149 d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
Shailabh Nagar6f449932006-07-14 00:24:41 -0700150 d->blkio_count += tsk->delays->blkio_count;
151 d->swapin_count += tsk->delays->swapin_count;
Keika Kobayashi016ae212008-07-25 01:48:53 -0700152 d->freepages_count += tsk->delays->freepages_count;
Peter Zijlstra64efade2006-11-05 23:52:10 -0800153 spin_unlock_irqrestore(&tsk->delays->lock, flags);
Shailabh Nagar6f449932006-07-14 00:24:41 -0700154
Shailabh Nagar6f449932006-07-14 00:24:41 -0700155 return 0;
156}
Shailabh Nagar25890452006-07-14 00:24:43 -0700157
158__u64 __delayacct_blkio_ticks(struct task_struct *tsk)
159{
160 __u64 ret;
Peter Zijlstra64efade2006-11-05 23:52:10 -0800161 unsigned long flags;
Shailabh Nagar25890452006-07-14 00:24:43 -0700162
Peter Zijlstra64efade2006-11-05 23:52:10 -0800163 spin_lock_irqsave(&tsk->delays->lock, flags);
Shailabh Nagar25890452006-07-14 00:24:43 -0700164 ret = nsec_to_clock_t(tsk->delays->blkio_delay +
165 tsk->delays->swapin_delay);
Peter Zijlstra64efade2006-11-05 23:52:10 -0800166 spin_unlock_irqrestore(&tsk->delays->lock, flags);
Shailabh Nagar25890452006-07-14 00:24:43 -0700167 return ret;
168}
169
Keika Kobayashi873b4772008-07-25 01:48:52 -0700170void __delayacct_freepages_start(void)
171{
172 delayacct_start(&current->delays->freepages_start);
173}
174
175void __delayacct_freepages_end(void)
176{
177 delayacct_end(&current->delays->freepages_start,
178 &current->delays->freepages_end,
179 &current->delays->freepages_delay,
180 &current->delays->freepages_count);
181}
182