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| author |   Ming Lei <tom.leiming@gmail.com> | 2014-05-10 15:43:14 -0600 |
|---|---|---|
| committer |   Jens Axboe <axboe@fb.com> | 2014-05-10 15:43:14 -0600 |
| commit | 9d3d21aeb4f194cd7ac205abe68b14b47ae736a8 (patch) | |
| tree | 18b1306aa0a86c1c987bab5d3f2e9610f47bbb8b /block/blk-mq-tag.c | |
| parent | blk-mq: bitmap tag: remove barrier in bt_clear_tag() (diff) | |
| download | linux-dev-9d3d21aeb4f194cd7ac205abe68b14b47ae736a8.tar.xz linux-dev-9d3d21aeb4f194cd7ac205abe68b14b47ae736a8.zip | |
blk-mq: bitmap tag: select random tag betweet 0 and (depth - 1)
The selected tag should be selected at random between 0 and
(depth - 1) with probability 1/depth, instead between 0 and
(depth - 2) with probability 1/(depth - 1).
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-mq-tag.c')
| -rw-r--r-- | block/blk-mq-tag.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 5a83d8e587f7..f196e60178f4 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -449,10 +449,7 @@ void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *tag) { unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; - if (depth > 1) - *tag = prandom_u32() % (depth - 1); - else - *tag = 0; + *tag = prandom_u32() % depth; } ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page) |