diff options
Diffstat (limited to 'include/linux/elevator.h')
| -rw-r--r-- | include/linux/elevator.h | 114 |
1 files changed, 83 insertions, 31 deletions
diff --git a/include/linux/elevator.h b/include/linux/elevator.h index 988862534..b1f56316b 100644 --- a/include/linux/elevator.h +++ b/include/linux/elevator.h @@ -3,13 +3,15 @@ #define ELEVATOR_DEBUG -struct elevator_s; -typedef struct elevator_s elevator_t; - typedef void (elevator_fn) (struct request *, elevator_t *, struct list_head *, struct list_head *, int); +typedef int (elevator_merge_fn) (request_queue_t *, struct request **, + struct buffer_head *, int, int *, int *); + +typedef void (elevator_dequeue_fn) (struct request *); + struct elevator_s { int sequence; @@ -22,24 +24,20 @@ struct elevator_s int read_pendings; elevator_fn * elevator_fn; + elevator_merge_fn *elevator_merge_fn; + elevator_dequeue_fn *dequeue_fn; unsigned int queue_ID; }; -#define ELEVATOR_DEFAULTS \ -((elevator_t) { \ - 0, /* sequence */ \ - \ - 128, /* read_latency */ \ - 8192, /* write_latency */ \ - 32, /* max_bomb_segments */ \ - \ - 0, /* nr_segments */ \ - 0, /* read_pendings */ \ - \ - elevator_default, /* elevator_fn */ \ - }) - +void elevator_default(struct request *, elevator_t *, struct list_head *, struct list_head *, int); +int elevator_default_merge(request_queue_t *, struct request **, struct buffer_head *, int, int *, int *); +void elevator_default_dequeue(struct request *); +void elevator_noop(struct request *, elevator_t *, struct list_head *, struct list_head *, int); +int elevator_noop_merge(request_queue_t *, struct request **, struct buffer_head *, int, int *, int *); +void elevator_noop_dequeue(struct request *); +void elevator_linus(struct request *, elevator_t *, struct list_head *, struct list_head *, int); +int elevator_linus_merge(request_queue_t *, struct request **, struct buffer_head *, int, int *, int *); typedef struct blkelv_ioctl_arg_s { int queue_ID; @@ -54,13 +52,12 @@ typedef struct blkelv_ioctl_arg_s { extern int blkelvget_ioctl(elevator_t *, blkelv_ioctl_arg_t *); extern int blkelvset_ioctl(elevator_t *, const blkelv_ioctl_arg_t *); - -extern void elevator_init(elevator_t *); +extern void elevator_init(elevator_t *, elevator_t); #ifdef ELEVATOR_DEBUG -extern void elevator_debug(request_queue_t *, kdev_t); +extern void elevator_default_debug(request_queue_t *, kdev_t); #else -#define elevator_debug(a,b) do { } while(0) +#define elevator_default_debug(a,b) do { } while(0) #endif #define elevator_sequence_after(a,b) ((int)((b)-(a)) < 0) @@ -69,6 +66,13 @@ extern void elevator_debug(request_queue_t *, kdev_t); #define elevator_sequence_before_eq(a,b) elevator_sequence_after_eq(b,a) /* + * Return values from elevator merger + */ +#define ELEVATOR_NO_MERGE 0 +#define ELEVATOR_FRONT_MERGE 1 +#define ELEVATOR_BACK_MERGE 2 + +/* * This is used in the elevator algorithm. We don't prioritise reads * over writes any more --- although reads are more time-critical than * writes, by treating them equally we increase filesystem throughput. @@ -79,12 +83,12 @@ extern void elevator_debug(request_queue_t *, kdev_t); (s1)->sector < (s2)->sector)) || \ (s1)->rq_dev < (s2)->rq_dev) -static inline void elevator_merge_requests(elevator_t * e, struct request * req, struct request * next) +static inline void elevator_merge_requests(struct request * req, struct request * next) { if (elevator_sequence_before(next->elevator_sequence, req->elevator_sequence)) req->elevator_sequence = next->elevator_sequence; if (req->cmd == READ) - e->read_pendings--; + req->e->read_pendings--; } @@ -93,23 +97,23 @@ static inline int elevator_sequence(elevator_t * e, int latency) return latency + e->sequence; } -#define elevator_merge_before(q, req, lat) __elevator_merge((q), (req), (lat), 0) -#define elevator_merge_after(q, req, lat) __elevator_merge((q), (req), (lat), 1) -static inline void __elevator_merge(elevator_t * elevator, struct request * req, int latency, int after) +#define elevator_merge_before(req, lat) __elevator_merge((req), (lat), 0) +#define elevator_merge_after(req, lat) __elevator_merge((req), (lat), 1) +static inline void __elevator_merge(struct request * req, int latency, int after) { - int sequence = elevator_sequence(elevator, latency); + int sequence = elevator_sequence(req->e, latency); if (after) sequence -= req->nr_segments; if (elevator_sequence_before(sequence, req->elevator_sequence)) req->elevator_sequence = sequence; } -static inline void elevator_account_request(elevator_t * elevator, struct request * req) +static inline void elevator_account_request(struct request * req) { - elevator->sequence++; + req->e->sequence++; if (req->cmd == READ) - elevator->read_pendings++; - elevator->nr_segments++; + req->e->read_pendings++; + req->e->nr_segments++; } static inline int elevator_request_latency(elevator_t * elevator, int rw) @@ -123,4 +127,52 @@ static inline int elevator_request_latency(elevator_t * elevator, int rw) return latency; } +#define ELEVATOR_DEFAULT \ +((elevator_t) { \ + 0, /* sequence */ \ + \ + 100000, /* read_latency */ \ + 100000, /* write_latency */ \ + 128, /* max_bomb_segments */ \ + \ + 0, /* nr_segments */ \ + 0, /* read_pendings */ \ + \ + elevator_default, /* elevator_fn */ \ + elevator_default_merge, /* elevator_merge_fn */ \ + elevator_default_dequeue, /* dequeue_fn */ \ + }) + +#define ELEVATOR_NOOP \ +((elevator_t) { \ + 0, /* sequence */ \ + \ + 0, /* read_latency */ \ + 0, /* write_latency */ \ + 0, /* max_bomb_segments */ \ + \ + 0, /* nr_segments */ \ + 0, /* read_pendings */ \ + \ + elevator_noop, /* elevator_fn */ \ + elevator_noop_merge, /* elevator_merge_fn */ \ + elevator_noop_dequeue, /* dequeue_fn */ \ + }) + +#define ELEVATOR_LINUS \ +((elevator_t) { \ + 0, /* not used */ \ + \ + 1000000, /* read passovers */ \ + 2000000, /* write passovers */ \ + 0, /* max_bomb_segments */ \ + \ + 0, /* not used */ \ + 0, /* not used */ \ + \ + elevator_linus, /* elevator_fn */ \ + elevator_linus_merge, /* elevator_merge_fn */ \ + elevator_noop_dequeue, /* dequeue_fn */ \ + }) + #endif |