linux-imx

/*

 * cgroups support for the BFQ I/O scheduler.

 *

 *  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 will 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/module.h>

#include <linux/slab.h>

#include <linux/blkdev.h>

#include <linux/cgroup.h>

#include <linux/elevator.h>

#include <linux/ktime.h>

#include <linux/rbtree.h>

#include <linux/ioprio.h>

#include <linux/sbitmap.h>

#include <linux/delay.h>

​

#include "bfq-iosched.h"

​

#if defined(CONFIG_BFQ_GROUP_IOSCHED) &&  defined(CONFIG_DEBUG_BLK_CGROUP)

​

/* bfqg stats flags */

enum bfqg_stats_flags {

    BFQG_stats_waiting = 0,

    BFQG_stats_idling,

    BFQG_stats_empty,

};

​

#define BFQG_FLAG_FNS(name)                     \

static void bfqg_stats_mark_##name(struct bfqg_stats *stats)    \

{                                   \

    stats->flags |= (1 << BFQG_stats_##name);           \

}                                   \

static void bfqg_stats_clear_##name(struct bfqg_stats *stats)   \

{                                   \

    stats->flags &= ~(1 << BFQG_stats_##name);          \

}                                   \

static int bfqg_stats_##name(struct bfqg_stats *stats)      \

{                                   \

    return (stats->flags & (1 << BFQG_stats_##name)) != 0;      \

}                                   \

​

BFQG_FLAG_FNS(waiting)

BFQG_FLAG_FNS(idling)

BFQG_FLAG_FNS(empty)

#undef BFQG_FLAG_FNS

​

/* This should be called with the scheduler lock held. */

static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)

{

    u64 now;

​

    if (!bfqg_stats_waiting(stats))

        return;

​

    now = ktime_get_ns();

    if (now > stats->start_group_wait_time)

        blkg_stat_add(&stats->group_wait_time,

                  now - stats->start_group_wait_time);

    bfqg_stats_clear_waiting(stats);

}

​

/* This should be called with the scheduler lock held. */

static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,

                         struct bfq_group *curr_bfqg)

{

    struct bfqg_stats *stats = &bfqg->stats;

​

    if (bfqg_stats_waiting(stats))

        return;

    if (bfqg == curr_bfqg)

        return;

    stats->start_group_wait_time = ktime_get_ns();

    bfqg_stats_mark_waiting(stats);

}

​

/* This should be called with the scheduler lock held. */

static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)

{

    u64 now;

​

    if (!bfqg_stats_empty(stats))

        return;

​

    now = ktime_get_ns();