I/O Request Scheduling

include/block/sched.h

struct bio_rqueue

struct bio_rqueue {
    struct list_head  list;
    uint64_t          request_count;
    bool              dirty;
};

struct bio_rqueue referenced types:

• struct list_head

struct bio_scheduler

struct bio_scheduler {
    struct block_device  *disk;
    struct mutex         lock;
    uint64_t             total_requests;
    struct bio_rqueue    queues[BIO_SCHED_LEVELS];
    bool                 defer_pending;
};

struct bio_scheduler referenced types:

• struct block_device
• struct mutex
• struct bio_rqueue

struct bio_scheduler_ops

struct bio_scheduler_ops {
    bool      (*should_coalesce)(struct block_device *dev, const struct bio_request *a, const struct bio_request *b);
    void      (*do_coalesce)(struct block_device *dev, struct bio_request *into, struct bio_request *from);
    void      (*reorder)(struct block_device *dev);
    uint32_t  max_wait_time[BIO_SCHED_LEVELS];
    uint32_t  dispatch_threshold;
    uint64_t  boost_occupance_limit[BIO_SCHED_LEVELS];
    uint64_t  tick_ms;
    uint64_t  min_wait_ms;
};

noop_should_coalesce

bool noop_should_coalesce(struct block_device *disk, struct bio_request *a, struct bio_request *b);

noop_should_coalesce referenced types:

• struct block_device
• struct bio_request

noop_do_coalesce

void noop_do_coalesce(struct block_device *disk, struct bio_request *into, struct bio_request *from);

noop_do_coalesce referenced types:

• struct block_device
• struct bio_request

noop_reorder

void noop_reorder(struct block_device *disk);

noop_reorder referenced types:

• struct block_device

bio_sched_enqueue

void bio_sched_enqueue(struct block_device *disk, struct bio_request *req);

bio_sched_enqueue referenced types:

• struct block_device
• struct bio_request

bio_sched_dequeue

void bio_sched_dequeue(struct block_device *disk, struct bio_request *req, bool already_locked);

bio_sched_dequeue referenced types:

• struct block_device
• struct bio_request

bio_sched_enqueue_internal

void bio_sched_enqueue_internal(struct bio_scheduler *sched, struct bio_request *req);

bio_sched_enqueue_internal referenced types:

• struct bio_scheduler
• struct bio_request

bio_sched_dequeue_internal

void bio_sched_dequeue_internal(struct bio_scheduler *sched, struct bio_request *req);

bio_sched_dequeue_internal referenced types:

• struct bio_scheduler
• struct bio_request

bio_sched_dispatch_partial

void bio_sched_dispatch_partial(struct block_device *disk, enum bio_request_priority prio);

bio_sched_dispatch_partial referenced types:

• struct block_device
• enum bio_request_priority

bio_sched_dispatch_all

void bio_sched_dispatch_all(struct block_device *disk);

bio_sched_dispatch_all referenced types:

• struct block_device

bio_sched_try_early_dispatch

void bio_sched_try_early_dispatch(struct bio_scheduler *sched);

bio_sched_try_early_dispatch referenced types:

• struct bio_scheduler

bio_sched_try_coalesce

bool bio_sched_try_coalesce(struct bio_scheduler *sched);

bio_sched_try_coalesce referenced types:

• struct bio_scheduler

bio_sched_boost_starved

bool bio_sched_boost_starved(struct bio_scheduler *sched);

bio_sched_boost_starved referenced types:

• struct bio_scheduler

bio_sched_create

struct bio_scheduler * bio_sched_create(struct block_device *disk, struct bio_scheduler_ops *ops);

bio_sched_create referenced types:

• struct bio_scheduler
• struct block_device
• struct bio_scheduler_ops

update_request_timestamp

void update_request_timestamp(struct bio_request *req);

update_request_timestamp referenced types:

• struct bio_request

submit_if_urgent

bool submit_if_urgent(struct bio_scheduler *sched, struct bio_request *req);

submit_if_urgent referenced types:

• struct bio_scheduler
• struct bio_request

sched_is_empty

bool sched_is_empty(struct bio_scheduler *sched);

sched_is_empty referenced types:

• struct bio_scheduler

submit_if_skip_sched

bool submit_if_skip_sched(struct bio_scheduler *sched, struct bio_request *req);

submit_if_skip_sched referenced types:

• struct bio_scheduler
• struct bio_request

Defines

BIO_SCHED_LEVELS

#define BIO_SCHED_LEVELS 5

BIO_SCHED_MAX

#define BIO_SCHED_MAX (BIO_SCHED_LEVELS - 1)

BIO_SCHED_STARVATION_BOOST

#define BIO_SCHED_STARVATION_BOOST 1

BIO_SCHED_BOOST_SHIFT_LIMIT

#define BIO_SCHED_BOOST_SHIFT_LIMIT 4

BIO_SCHED_COALESCE_SCAN_LIMIT

#define BIO_SCHED_COALESCE_SCAN_LIMIT 8

BIO_SCHED_MAX_BOOST_SCAN

#define BIO_SCHED_MAX_BOOST_SCAN 32

BIO_SCHED_MAX_COALESCES

#define BIO_SCHED_MAX_COALESCES 4

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