Shailabh Nagar | ca74e92 | 2006-07-14 00:24:36 -0700 | [diff] [blame^] | 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/time.h> |
| 19 | #include <linux/sysctl.h> |
| 20 | #include <linux/delayacct.h> |
| 21 | |
| 22 | int delayacct_on __read_mostly; /* Delay accounting turned on/off */ |
| 23 | kmem_cache_t *delayacct_cache; |
| 24 | |
| 25 | static int __init delayacct_setup_enable(char *str) |
| 26 | { |
| 27 | delayacct_on = 1; |
| 28 | return 1; |
| 29 | } |
| 30 | __setup("delayacct", delayacct_setup_enable); |
| 31 | |
| 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 | } |
| 41 | |
| 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 | } |
| 48 | |
| 49 | void __delayacct_tsk_exit(struct task_struct *tsk) |
| 50 | { |
| 51 | kmem_cache_free(delayacct_cache, tsk->delays); |
| 52 | tsk->delays = NULL; |
| 53 | } |
| 54 | |
| 55 | /* |
| 56 | * Start accounting for a delay statistic using |
| 57 | * its starting timestamp (@start) |
| 58 | */ |
| 59 | |
| 60 | static inline void delayacct_start(struct timespec *start) |
| 61 | { |
| 62 | do_posix_clock_monotonic_gettime(start); |
| 63 | } |
| 64 | |
| 65 | /* |
| 66 | * Finish delay accounting for a statistic using |
| 67 | * its timestamps (@start, @end), accumalator (@total) and @count |
| 68 | */ |
| 69 | |
| 70 | static void delayacct_end(struct timespec *start, struct timespec *end, |
| 71 | u64 *total, u32 *count) |
| 72 | { |
| 73 | struct timespec ts; |
| 74 | s64 ns; |
| 75 | |
| 76 | do_posix_clock_monotonic_gettime(end); |
| 77 | ts = timespec_sub(*end, *start); |
| 78 | ns = timespec_to_ns(&ts); |
| 79 | if (ns < 0) |
| 80 | return; |
| 81 | |
| 82 | spin_lock(¤t->delays->lock); |
| 83 | *total += ns; |
| 84 | (*count)++; |
| 85 | spin_unlock(¤t->delays->lock); |
| 86 | } |
| 87 | |