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authorShaohua Li <shli@fb.com>2015-01-23 14:18:00 -0700
committerJens Axboe <axboe@fb.com>2015-01-23 14:18:00 -0700
commit24391c0dc57c3756a219defaa781e68637d6ab7d (patch)
tree4d0e5b213c017e622d69d916c9e13e7f6e805368 /include/linux/blk-mq.h
parentee1b6f7aff94019c09e73837054979063f722046 (diff)
blk-mq: add tag allocation policy
This is the blk-mq part to support tag allocation policy. The default allocation policy isn't changed (though it's not a strict FIFO). The new policy is round-robin for libata. But it's a try-best implementation. If multiple tasks are competing, the tags returned will be mixed (which is unavoidable even with !mq, as requests from different tasks can be mixed in queue) 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/linux/blk-mq.h')
-rw-r--r--include/linux/blk-mq.h8
1 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 5b6500c77ed2..86b08b1a5eba 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -147,6 +147,8 @@ enum {
BLK_MQ_F_SG_MERGE = 1 << 2,
BLK_MQ_F_SYSFS_UP = 1 << 3,
BLK_MQ_F_DEFER_ISSUE = 1 << 4,
+ BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
+ BLK_MQ_F_ALLOC_POLICY_BITS = 1,
BLK_MQ_S_STOPPED = 0,
BLK_MQ_S_TAG_ACTIVE = 1,
@@ -155,6 +157,12 @@ enum {
BLK_MQ_CPU_WORK_BATCH = 8,
};
+#define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
+ ((flags >> BLK_MQ_F_ALLOC_POLICY_START_BIT) & \
+ ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1))
+#define BLK_ALLOC_POLICY_TO_MQ_FLAG(policy) \
+ ((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
+ << BLK_MQ_F_ALLOC_POLICY_START_BIT)
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
void blk_mq_finish_init(struct request_queue *q);