diff options
author | Jens Axboe <jens.axboe@oracle.com> | 2009-04-06 14:48:01 +0200 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-06 08:04:53 -0700 |
commit | 1faa16d22877f4839bd433547d770c676d1d964c (patch) | |
tree | 9a0d50be1ef0358c1f53d7107413100904e7d526 /include/linux/blkdev.h | |
parent | 0221c81b1b8eb0cbb6b30a0ced52ead32d2b4e4c (diff) | |
download | op-kernel-dev-1faa16d22877f4839bd433547d770c676d1d964c.zip op-kernel-dev-1faa16d22877f4839bd433547d770c676d1d964c.tar.gz |
block: change the request allocation/congestion logic to be sync/async based
This makes sure that we never wait on async IO for sync requests, instead
of doing the split on writes vs reads.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/blkdev.h')
-rw-r--r-- | include/linux/blkdev.h | 52 |
1 files changed, 35 insertions, 17 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 465d6ba..67dae3b 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -38,6 +38,10 @@ struct request; typedef void (rq_end_io_fn)(struct request *, int); struct request_list { + /* + * count[], starved[], and wait[] are indexed by + * BLK_RW_SYNC/BLK_RW_ASYNC + */ int count[2]; int starved[2]; int elvpriv; @@ -66,6 +70,11 @@ enum rq_cmd_type_bits { REQ_TYPE_ATA_PC, }; +enum { + BLK_RW_ASYNC = 0, + BLK_RW_SYNC = 1, +}; + /* * For request of type REQ_TYPE_LINUX_BLOCK, rq->cmd[0] is the opcode being * sent down (similar to how REQ_TYPE_BLOCK_PC means that ->cmd[] holds a @@ -103,7 +112,7 @@ enum rq_flag_bits { __REQ_QUIET, /* don't worry about errors */ __REQ_PREEMPT, /* set for "ide_preempt" requests */ __REQ_ORDERED_COLOR, /* is before or after barrier */ - __REQ_RW_SYNC, /* request is sync (O_DIRECT) */ + __REQ_RW_SYNC, /* request is sync (sync write or read) */ __REQ_ALLOCED, /* request came from our alloc pool */ __REQ_RW_META, /* metadata io request */ __REQ_COPY_USER, /* contains copies of user pages */ @@ -438,8 +447,8 @@ struct request_queue #define QUEUE_FLAG_CLUSTER 0 /* cluster several segments into 1 */ #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */ #define QUEUE_FLAG_STOPPED 2 /* queue is stopped */ -#define QUEUE_FLAG_READFULL 3 /* read queue has been filled */ -#define QUEUE_FLAG_WRITEFULL 4 /* write queue has been filled */ +#define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */ +#define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */ #define QUEUE_FLAG_DEAD 5 /* queue being torn down */ #define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */ #define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */ @@ -611,32 +620,41 @@ enum { #define rq_data_dir(rq) ((rq)->cmd_flags & 1) /* - * We regard a request as sync, if it's a READ or a SYNC write. + * We regard a request as sync, if either a read or a sync write */ -#define rq_is_sync(rq) (rq_data_dir((rq)) == READ || (rq)->cmd_flags & REQ_RW_SYNC) +static inline bool rw_is_sync(unsigned int rw_flags) +{ + return !(rw_flags & REQ_RW) || (rw_flags & REQ_RW_SYNC); +} + +static inline bool rq_is_sync(struct request *rq) +{ + return rw_is_sync(rq->cmd_flags); +} + #define rq_is_meta(rq) ((rq)->cmd_flags & REQ_RW_META) -static inline int blk_queue_full(struct request_queue *q, int rw) +static inline int blk_queue_full(struct request_queue *q, int sync) { - if (rw == READ) - return test_bit(QUEUE_FLAG_READFULL, &q->queue_flags); - return test_bit(QUEUE_FLAG_WRITEFULL, &q->queue_flags); + if (sync) + return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags); + return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags); } -static inline void blk_set_queue_full(struct request_queue *q, int rw) +static inline void blk_set_queue_full(struct request_queue *q, int sync) { - if (rw == READ) - queue_flag_set(QUEUE_FLAG_READFULL, q); + if (sync) + queue_flag_set(QUEUE_FLAG_SYNCFULL, q); else - queue_flag_set(QUEUE_FLAG_WRITEFULL, q); + queue_flag_set(QUEUE_FLAG_ASYNCFULL, q); } -static inline void blk_clear_queue_full(struct request_queue *q, int rw) +static inline void blk_clear_queue_full(struct request_queue *q, int sync) { - if (rw == READ) - queue_flag_clear(QUEUE_FLAG_READFULL, q); + if (sync) + queue_flag_clear(QUEUE_FLAG_SYNCFULL, q); else - queue_flag_clear(QUEUE_FLAG_WRITEFULL, q); + queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q); } |