diff options
| author | Shaohua Li <shli@fb.com> | 2015-01-15 17:32:25 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-01-23 14:15:46 -0700 |
| commit | ee1b6f7aff94019c09e73837054979063f722046 (patch) | |
| tree | 79c7b943d7c6d62fec1874afd2c50964de054aa0 /include | |
| parent | bb5c3cdda37aad22996d6da2addd58cadc0436c0 (diff) | |
| download | linux-ee1b6f7aff94019c09e73837054979063f722046.tar.bz2 | |
block: support different tag allocation policy
The libata tag allocation is using a round-robin policy. Next patch will
make libata use block generic tag allocation, so let's add a policy to
tag allocation.
Currently two policies: FIFO (default) and round-robin.
Cc: Jens Axboe <axboe@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 8 | ||||
| -rw-r--r-- | include/scsi/scsi_host.h | 3 | ||||
| -rw-r--r-- | include/scsi/scsi_tcq.h | 3 |
3 files changed, 11 insertions, 3 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 4c4b732d7556..6f388fd1c11c 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -272,7 +272,11 @@ struct blk_queue_tag { int max_depth; /* what we will send to device */ int real_max_depth; /* what the array can hold */ atomic_t refcnt; /* map can be shared */ + int alloc_policy; /* tag allocation policy */ + int next_tag; /* next tag */ }; +#define BLK_TAG_ALLOC_FIFO 0 /* allocate starting from 0 */ +#define BLK_TAG_ALLOC_RR 1 /* allocate starting from last allocated tag */ #define BLK_SCSI_MAX_CMDS (256) #define BLK_SCSI_CMD_PER_LONG (BLK_SCSI_MAX_CMDS / (sizeof(long) * 8)) @@ -1139,11 +1143,11 @@ static inline bool blk_needs_flush_plug(struct task_struct *tsk) extern int blk_queue_start_tag(struct request_queue *, struct request *); extern struct request *blk_queue_find_tag(struct request_queue *, int); extern void blk_queue_end_tag(struct request_queue *, struct request *); -extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *); +extern int blk_queue_init_tags(struct request_queue *, int, struct blk_queue_tag *, int); extern void blk_queue_free_tags(struct request_queue *); extern int blk_queue_resize_tags(struct request_queue *, int); extern void blk_queue_invalidate_tags(struct request_queue *); -extern struct blk_queue_tag *blk_init_tags(int); +extern struct blk_queue_tag *blk_init_tags(int, int); extern void blk_free_tags(struct blk_queue_tag *); static inline struct request *blk_map_queue_find_tag(struct blk_queue_tag *bqt, diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 019e66858ce6..e113c757d555 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -402,6 +402,9 @@ struct scsi_host_template { */ unsigned char present; + /* If use block layer to manage tags, this is tag allocation policy */ + int tag_alloc_policy; + /* * Let the block layer assigns tags to all commands. */ diff --git a/include/scsi/scsi_tcq.h b/include/scsi/scsi_tcq.h index 9708b28bd2aa..b27977e8aaed 100644 --- a/include/scsi/scsi_tcq.h +++ b/include/scsi/scsi_tcq.h @@ -66,7 +66,8 @@ static inline int scsi_init_shared_tag_map(struct Scsi_Host *shost, int depth) * devices on the shared host (for libata) */ if (!shost->bqt) { - shost->bqt = blk_init_tags(depth); + shost->bqt = blk_init_tags(depth, + shost->hostt->tag_alloc_policy); if (!shost->bqt) return -ENOMEM; } |