Line data    Source code

       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/taskstats.h>
      19             : #include <linux/time.h>
      20             : #include <linux/sysctl.h>
      21             : #include <linux/delayacct.h>
      22             : #include <linux/module.h>
      23             : 
      24             : int delayacct_on __read_mostly = 1;     /* Delay accounting turned on/off */
      25             : EXPORT_SYMBOL_GPL(delayacct_on);
      26             : struct kmem_cache *delayacct_cache;
      27             : 
      28           0 : static int __init delayacct_setup_disable(char *str)
      29             : {
      30           0 :         delayacct_on = 0;
      31           0 :         return 1;
      32             : }
      33             : __setup("nodelayacct", delayacct_setup_disable);
      34             : 
      35           1 : void delayacct_init(void)
      36             : {
      37           1 :         delayacct_cache = KMEM_CACHE(task_delay_info, SLAB_PANIC);
      38             :         delayacct_tsk_init(&init_task);
      39           1 : }
      40             : 
      41        2994 : void __delayacct_tsk_init(struct task_struct *tsk)
      42             : {
      43        5988 :         tsk->delays = kmem_cache_zalloc(delayacct_cache, GFP_KERNEL);
      44             :         if (tsk->delays)
      45             :                 spin_lock_init(&tsk->delays->lock);
      46        2994 : }
      47             : 
      48             : /*
      49             :  * Finish delay accounting for a statistic using its timestamps (@start),
      50             :  * accumalator (@total) and @count
      51             :  */
      52        1509 : static void delayacct_end(u64 *start, u64 *total, u32 *count)
      53             : {
      54        1509 :         s64 ns = ktime_get_ns() - *start;
      55             :         unsigned long flags;
      56             : 
      57        1509 :         if (ns > 0) {
      58        1509 :                 spin_lock_irqsave(&current->delays->lock, flags);
      59        1509 :                 *total += ns;
      60        1509 :                 (*count)++;
      61             :                 spin_unlock_irqrestore(&current->delays->lock, flags);
      62             :         }
      63        1509 : }
      64             : 
      65        1509 : void __delayacct_blkio_start(void)
      66             : {
      67        3018 :         current->delays->blkio_start = ktime_get_ns();
      68        1509 : }
      69             : 
      70        1509 : void __delayacct_blkio_end(void)
      71             : {
      72        1509 :         if (current->delays->flags & DELAYACCT_PF_SWAPIN)
      73             :                 /* Swapin block I/O */
      74           0 :                 delayacct_end(&current->delays->blkio_start,
      75             :                         &current->delays->swapin_delay,
      76             :                         &current->delays->swapin_count);
      77             :         else    /* Other block I/O */
      78        1509 :                 delayacct_end(&current->delays->blkio_start,
      79             :                         &current->delays->blkio_delay,
      80             :                         &current->delays->blkio_count);
      81        1509 : }
      82             : 
      83           0 : int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
      84             : {
      85             :         cputime_t utime, stime, stimescaled, utimescaled;
      86             :         unsigned long long t2, t3;
      87             :         unsigned long flags, t1;
      88             :         s64 tmp;
      89             : 
      90             :         task_cputime(tsk, &utime, &stime);
      91           0 :         tmp = (s64)d->cpu_run_real_total;
      92           0 :         tmp += cputime_to_nsecs(utime + stime);
      93           0 :         d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
      94             : 
      95             :         task_cputime_scaled(tsk, &utimescaled, &stimescaled);
      96           0 :         tmp = (s64)d->cpu_scaled_run_real_total;
      97           0 :         tmp += cputime_to_nsecs(utimescaled + stimescaled);
      98           0 :         d->cpu_scaled_run_real_total =
      99           0 :                 (tmp < (s64)d->cpu_scaled_run_real_total) ? 0 : tmp;
     100             : 
     101             :         /*
     102             :          * No locking available for sched_info (and too expensive to add one)
     103             :          * Mitigate by taking snapshot of values
     104             :          */
     105           0 :         t1 = tsk->sched_info.pcount;
     106           0 :         t2 = tsk->sched_info.run_delay;
     107           0 :         t3 = tsk->se.sum_exec_runtime;
     108             : 
     109           0 :         d->cpu_count += t1;
     110             : 
     111           0 :         tmp = (s64)d->cpu_delay_total + t2;
     112           0 :         d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
     113             : 
     114           0 :         tmp = (s64)d->cpu_run_virtual_total + t3;
     115           0 :         d->cpu_run_virtual_total =
     116           0 :                 (tmp < (s64)d->cpu_run_virtual_total) ?   0 : tmp;
     117             : 
     118             :         /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
     119             : 
     120           0 :         spin_lock_irqsave(&tsk->delays->lock, flags);
     121           0 :         tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
     122           0 :         d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
     123           0 :         tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
     124           0 :         d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
     125           0 :         tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
     126           0 :         d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
     127           0 :         d->blkio_count += tsk->delays->blkio_count;
     128           0 :         d->swapin_count += tsk->delays->swapin_count;
     129           0 :         d->freepages_count += tsk->delays->freepages_count;
     130             :         spin_unlock_irqrestore(&tsk->delays->lock, flags);
     131             : 
     132           0 :         return 0;
     133             : }
     134             : 
     135         706 : __u64 __delayacct_blkio_ticks(struct task_struct *tsk)
     136             : {
     137             :         __u64 ret;
     138             :         unsigned long flags;
     139             : 
     140         706 :         spin_lock_irqsave(&tsk->delays->lock, flags);
     141        1412 :         ret = nsec_to_clock_t(tsk->delays->blkio_delay +
     142         706 :                                 tsk->delays->swapin_delay);
     143             :         spin_unlock_irqrestore(&tsk->delays->lock, flags);
     144         706 :         return ret;
     145             : }
     146             : 
     147           0 : void __delayacct_freepages_start(void)
     148             : {
     149           0 :         current->delays->freepages_start = ktime_get_ns();
     150           0 : }
     151             : 
     152           0 : void __delayacct_freepages_end(void)
     153             : {
     154           0 :         delayacct_end(&current->delays->freepages_start,
     155             :                         &current->delays->freepages_delay,
     156             :                         &current->delays->freepages_count);
     157           0 : }
     158             :