Subversion Repositories test_project

/* 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/time.h>

#include <linux/sysctl.h>

#include <linux/delayacct.h>

int delayacct_on __read_mostly = 1;     /* Delay accounting turned on/off */

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);

        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);

}

/*

 * Start accounting for a delay statistic using

 * its starting timestamp (@start)

 */

static inline void delayacct_start(struct timespec *start)

{

        do_posix_clock_monotonic_gettime(start);

}

/*

 * Finish delay accounting for a statistic using

 * its timestamps (@start, @end), accumalator (@total) and @count

 */

static void delayacct_end(struct timespec *start, struct timespec *end,

                                u64 *total, u32 *count)

{

        struct timespec ts;

        s64 ns;

        unsigned long flags;

        do_posix_clock_monotonic_gettime(end);

        ts = timespec_sub(*end, *start);

        ns = timespec_to_ns(&ts);

        if (ns < 0)

                return;

        spin_lock_irqsave(&current->delays->lock, flags);

        *total += ns;

        (*count)++;

        spin_unlock_irqrestore(&current->delays->lock, flags);

}

void __delayacct_blkio_start(void)

{

        delayacct_start(&current->delays->blkio_start);

}

void __delayacct_blkio_end(void)

{

        if (current->delays->flags & DELAYACCT_PF_SWAPIN)

                /* Swapin block I/O */

                delayacct_end(&current->delays->blkio_start,

                        &current->delays->blkio_end,

                        &current->delays->swapin_delay,

                        &current->delays->swapin_count);

        else    /* Other block I/O */

                delayacct_end(&current->delays->blkio_start,

                        &current->delays->blkio_end,

                        &current->delays->blkio_delay,

                        &current->delays->blkio_count);

}

int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)

{

        s64 tmp;

        unsigned long t1;

        unsigned long long t2, t3;

        unsigned long flags;

        struct timespec ts;

        /* Though tsk->delays accessed later, early exit avoids

         * unnecessary returning of other data

         */

        if (!tsk->delays)

                goto done;

        tmp = (s64)d->cpu_run_real_total;

        cputime_to_timespec(tsk->utime + tsk->stime, &ts);

        tmp += timespec_to_ns(&ts);

        d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;

        tmp = (s64)d->cpu_scaled_run_real_total;

        cputime_to_timespec(tsk->utimescaled + tsk->stimescaled, &ts);

        tmp += timespec_to_ns(&ts);

        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->sched_info.cpu_time;

        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;

        d->blkio_count += tsk->delays->blkio_count;

        d->swapin_count += tsk->delays->swapin_count;

        spin_unlock_irqrestore(&tsk->delays->lock, flags);

done:

        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;

}