Skip to content
charmOS docs

I/O Request Scheduling

include/block/sched.h View source View on GitHub

Structs

Section titled “Structs”

bio_rqueue

Section titled “bio_rqueue”
struct bio_rqueue {
    struct list_head  list;
    uint64_t          request_count;
    bool              dirty;
};

bio_scheduler

Section titled “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;
};

bio_scheduler_ops

Section titled “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;
};

Functions

Section titled “Functions”

noop_should_coalesce

Section titled “noop_should_coalesce”
bool noop_should_coalesce(struct block_device *disk, const struct bio_request *a, const struct bio_request *b);

noop_do_coalesce

Section titled “noop_do_coalesce”
void noop_do_coalesce(struct block_device *disk, struct bio_request *into, struct bio_request *from);

noop_reorder

Section titled “noop_reorder”
void noop_reorder(struct block_device *disk);

bio_sched_enqueue

Section titled “bio_sched_enqueue”
void bio_sched_enqueue(struct block_device *disk, struct bio_request *req);

bio_sched_dequeue

Section titled “bio_sched_dequeue”
void bio_sched_dequeue(struct block_device *disk, struct bio_request *req, bool already_locked);

bio_sched_enqueue_internal

Section titled “bio_sched_enqueue_internal”
void bio_sched_enqueue_internal(struct bio_scheduler *sched, struct bio_request *req);

bio_sched_dequeue_internal

Section titled “bio_sched_dequeue_internal”
void bio_sched_dequeue_internal(struct bio_scheduler *sched, struct bio_request *req);

bio_sched_dispatch_partial

Section titled “bio_sched_dispatch_partial”
void bio_sched_dispatch_partial(struct block_device *disk, enum bio_request_priority prio);

bio_sched_dispatch_all

Section titled “bio_sched_dispatch_all”
void bio_sched_dispatch_all(struct block_device *disk);

bio_sched_try_early_dispatch

Section titled “bio_sched_try_early_dispatch”
void bio_sched_try_early_dispatch(struct bio_scheduler *sched);

bio_sched_try_coalesce

Section titled “bio_sched_try_coalesce”
bool bio_sched_try_coalesce(struct bio_scheduler *sched);

bio_sched_boost_starved

Section titled “bio_sched_boost_starved”
bool bio_sched_boost_starved(struct bio_scheduler *sched);

bio_sched_create

Section titled “bio_sched_create”
struct bio_scheduler * bio_sched_create(struct block_device *disk, struct bio_scheduler_ops *ops);

update_request_timestamp

Section titled “update_request_timestamp”
void update_request_timestamp(struct bio_request *req);

submit_if_urgent

Section titled “submit_if_urgent”
bool submit_if_urgent(struct bio_scheduler *sched, struct bio_request *req);

sched_is_empty

Section titled “sched_is_empty”
bool sched_is_empty(struct bio_scheduler *sched);

submit_if_skip_sched

Section titled “submit_if_skip_sched”
bool submit_if_skip_sched(struct bio_scheduler *sched, struct bio_request *req);

Macros

Section titled “Macros”

BIO_SCHED_LEVELS

Section titled “BIO_SCHED_LEVELS”
#define BIO_SCHED_LEVELS 5

BIO_SCHED_MAX

Section titled “BIO_SCHED_MAX”
#define BIO_SCHED_MAX (BIO_SCHED_LEVELS - 1)

BIO_SCHED_STARVATION_BOOST

Section titled “BIO_SCHED_STARVATION_BOOST”
#define BIO_SCHED_STARVATION_BOOST 1

BIO_SCHED_BOOST_SHIFT_LIMIT

Section titled “BIO_SCHED_BOOST_SHIFT_LIMIT”
#define BIO_SCHED_BOOST_SHIFT_LIMIT 4

BIO_SCHED_COALESCE_SCAN_LIMIT

Section titled “BIO_SCHED_COALESCE_SCAN_LIMIT”
#define BIO_SCHED_COALESCE_SCAN_LIMIT 8

BIO_SCHED_MAX_BOOST_SCAN

Section titled “BIO_SCHED_MAX_BOOST_SCAN”
#define BIO_SCHED_MAX_BOOST_SCAN 32

BIO_SCHED_MAX_COALESCES

Section titled “BIO_SCHED_MAX_COALESCES”
#define BIO_SCHED_MAX_COALESCES 4