| /* delayacct.c - per-task delay accounting |
| * |
| * Copyright (C) Shailabh Nagar, IBM Corp. 2006 |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it would be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See |
| * the GNU General Public License for more details. |
| */ |
| |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/taskstats.h> |
| #include <linux/time.h> |
| #include <linux/sysctl.h> |
| #include <linux/delayacct.h> |
| #include <linux/module.h> |
| |
| int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */ |
| EXPORT_SYMBOL_GPL(delayacct_on); |
| struct kmem_cache *delayacct_cache; |
| |
| static int __init delayacct_setup_disable(char *str) |
| { |
| delayacct_on = 0; |
| return 1; |
| } |
| __setup("nodelayacct", delayacct_setup_disable); |
| |
| void delayacct_init(void) |
| { |
| delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC|SLAB_ACCOUNT); |
| delayacct_tsk_init(&init_task); |
| } |
| |
| void __delayacct_tsk_init(struct task_struct *tsk) |
| { |
| tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL); |
| if (tsk->delays) |
| spin_lock_init(&tsk->delays->lock); |
| } |
| |
| /* |
| * Finish delay accounting for a statistic using its timestamps (@start), |
| * accumalator (@total) and @count |
| */ |
| static void delayacct_end(u64 *start, u64 *total, u32 *count) |
| { |
| s64 ns = ktime_get_ns() - *start; |
| unsigned long flags; |
| |
| if (ns > 0) { |
| spin_lock_irqsave(¤t->delays->lock, flags); |
| *total += ns; |
| (*count)++; |
| spin_unlock_irqrestore(¤t->delays->lock, flags); |
| } |
| } |
| |
| void __delayacct_blkio_start(void) |
| { |
| current->delays->blkio_start = ktime_get_ns(); |
| } |
| |
| void __delayacct_blkio_end(void) |
| { |
| if (current->delays->flags & DELAYACCT_PF_SWAPIN) |
| /* Swapin block I/O */ |
| delayacct_end(¤t->delays->blkio_start, |
| ¤t->delays->swapin_delay, |
| ¤t->delays->swapin_count); |
| else /* Other block I/O */ |
| delayacct_end(¤t->delays->blkio_start, |
| ¤t->delays->blkio_delay, |
| ¤t->delays->blkio_count); |
| } |
| |
| int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) |
| { |
| u64 utime, stime, stimescaled, utimescaled; |
| unsigned long long t2, t3; |
| unsigned long flags, t1; |
| s64 tmp; |
| |
| task_cputime(tsk, &utime, &stime); |
| tmp = (s64)d->cpu_run_real_total; |
| tmp += utime + stime; |
| d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp; |
| |
| task_cputime_scaled(tsk, &utimescaled, &stimescaled); |
| tmp = (s64)d->cpu_scaled_run_real_total; |
| tmp += utimescaled + stimescaled; |
| d->cpu_scaled_run_real_total = |
| (tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp; |
| |
| /* |
| * No locking available for sched_info (and too expensive to add one) |
| * Mitigate by taking snapshot of values |
| */ |
| t1 = tsk->sched_info.pcount; |
| t2 = tsk->sched_info.run_delay; |
| t3 = tsk->se.sum_exec_runtime; |
| |
| d->cpu_count += t1; |
| |
| tmp = (s64)d->cpu_delay_total + t2; |
| d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp; |
| |
| tmp = (s64)d->cpu_run_virtual_total + t3; |
| d->cpu_run_virtual_total = |
| (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp; |
| |
| /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ |
| |
| spin_lock_irqsave(&tsk->delays->lock, flags); |
| tmp = d->blkio_delay_total + tsk->delays->blkio_delay; |
| d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; |
| tmp = d->swapin_delay_total + tsk->delays->swapin_delay; |
| d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp; |
| tmp = d->freepages_delay_total + tsk->delays->freepages_delay; |
| d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp; |
| d->blkio_count += tsk->delays->blkio_count; |
| d->swapin_count += tsk->delays->swapin_count; |
| d->freepages_count += tsk->delays->freepages_count; |
| spin_unlock_irqrestore(&tsk->delays->lock, flags); |
| |
| return 0; |
| } |
| |
| __u64 __delayacct_blkio_ticks(struct task_struct *tsk) |
| { |
| __u64 ret; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&tsk->delays->lock, flags); |
| ret = nsec_to_clock_t(tsk->delays->blkio_delay + |
| tsk->delays->swapin_delay); |
| spin_unlock_irqrestore(&tsk->delays->lock, flags); |
| return ret; |
| } |
| |
| void __delayacct_freepages_start(void) |
| { |
| current->delays->freepages_start = ktime_get_ns(); |
| } |
| |
| void __delayacct_freepages_end(void) |
| { |
| delayacct_end(¤t->delays->freepages_start, |
| ¤t->delays->freepages_delay, |
| ¤t->delays->freepages_count); |
| } |
| |