From: Jan Kara jack@suse.cz
stable inclusion from linux-4.19.169 commit 9f8b5931be0bf003a8e90fcc93552089820fc2ee
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[ Upstream commit 6d4d273588378c65915acaf7b2ee74e9dd9c130a ]
BFQ computes number of tags it allows to be allocated for each request type based on tag bitmap. However it uses 1 << bitmap.shift as number of available tags which is wrong. 'shift' is just an internal bitmap value containing logarithm of how many bits bitmap uses in each bitmap word. Thus number of tags allowed for some request types can be far to low. Use proper bitmap.depth which has the number of tags instead.
Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- block/bfq-iosched.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 97b033b00d4e..0c2c0cd8546c 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5283,13 +5283,13 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd, * limit 'something'. */ /* no more than 50% of tags for async I/O */ - bfqd->word_depths[0][0] = max((1U << bt->sb.shift) >> 1, 1U); + bfqd->word_depths[0][0] = max(bt->sb.depth >> 1, 1U); /* * no more than 75% of tags for sync writes (25% extra tags * w.r.t. async I/O, to prevent async I/O from starving sync * writes) */ - bfqd->word_depths[0][1] = max(((1U << bt->sb.shift) * 3) >> 2, 1U); + bfqd->word_depths[0][1] = max((bt->sb.depth * 3) >> 2, 1U);
/* * In-word depths in case some bfq_queue is being weight- @@ -5299,9 +5299,9 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd, * shortage. */ /* no more than ~18% of tags for async I/O */ - bfqd->word_depths[1][0] = max(((1U << bt->sb.shift) * 3) >> 4, 1U); + bfqd->word_depths[1][0] = max((bt->sb.depth * 3) >> 4, 1U); /* no more than ~37% of tags for sync writes (~20% extra tags) */ - bfqd->word_depths[1][1] = max(((1U << bt->sb.shift) * 6) >> 4, 1U); + bfqd->word_depths[1][1] = max((bt->sb.depth * 6) >> 4, 1U);
for (i = 0; i < 2; i++) for (j = 0; j < 2; j++)