[PATCH 5/5] blk-mq: Lower minimum queue depth from 4 to 1

From: Alexander Gordeev
Date: Wed Aug 21 2013 - 11:26:50 EST


There is no reason to limit minimum queue depth.
Indeed, some ATA devices ask for the depth of 1.

Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
---
block/blk-mq-tag.c | 2 +-
block/blk-mq-tag.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index e74e18e..a115862 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -456,7 +456,7 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
tags->nr_tags = total_tags;
tags->reserved_tags = reserved_tags;
tags->max_cache = nr_cache;
- tags->batch_move = nr_cache / 2;
+ tags->batch_move = max(1u, nr_cache / 2);

/*
* Reserved tags are first
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 716ea79..947ba2c 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -14,7 +14,7 @@ extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);

enum {
- BLK_MQ_TAG_CACHE_MIN = 4,
+ BLK_MQ_TAG_CACHE_MIN = 1,
BLK_MQ_TAG_CACHE_MAX = 64,
};

--
1.7.7.6

--
Regards,
Alexander Gordeev
agordeev@xxxxxxxxxx
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