Skip to content
charmOS docs

I/O Request Scheduling

include/block/sched.h

Section titled “include/block/sched.h”

struct bio_rqueue

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

struct bio_rqueue referenced types:

struct bio_scheduler

Section titled “struct bio_scheduler”
struct bio_scheduler {
    struct generic_disk  *disk;
    struct mutex         lock;
    uint64_t             total_requests;
    struct bio_rqueue    queues[BIO_SCHED_LEVELS];
    bool                 defer_pending;
};

struct bio_scheduler referenced types:

struct bio_scheduler_ops

Section titled “struct bio_scheduler_ops”
struct bio_scheduler_ops {
    bool      (*should_coalesce)(struct generic_disk *dev, const struct bio_request *a, const struct bio_request *b);
    void      (*do_coalesce)(struct generic_disk *dev, struct bio_request *into, struct bio_request *from);
    void      (*reorder)(struct generic_disk *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;
};

update_request_timestamp

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

update_request_timestamp referenced types:

submit_if_urgent

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

submit_if_urgent referenced types:

sched_is_empty

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

sched_is_empty referenced types:

submit_if_skip_sched

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

submit_if_skip_sched referenced types:

Defines

Section titled “Defines”

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