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Revert "block/mq-deadline: use correct way to throttling write requests" 

The code "max(1U, 3 * (1U << shift)  / 4)" comes from the Kyber I/O
scheduler. The Kyber I/O scheduler maintains one internal queue per hwq
and hence derives its async_depth from the number of hwq tags. Using
this approach for the mq-deadline scheduler is wrong since the
mq-deadline scheduler maintains one internal queue for all hwqs
combined. Hence this revert.

Cc: stable@vger.kernel.org
Cc: Damien Le Moal <dlemoal@kernel.org>
Cc: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Cc: Zhiguo Niu <Zhiguo.Niu@unisoc.com>
Fixes: d47f9717e5 ("block/mq-deadline: use correct way to throttling write requests")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240313214218.1736147-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Bart Van Assche 2024-03-13 14:42:18 -07:00 committed by Jens Axboe
parent b874d4aae5
commit 256aab46e3
1 changed files with 1 additions and 2 deletions
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3
block/mq-deadline.c
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@ -646,9 +646,8 @@ static void dd_depth_updated(struct blk_mq_hw_ctx *hctx)
struct request_queue *q = hctx->queue;
struct deadline_data *dd = q->elevator->elevator_data;
struct blk_mq_tags *tags = hctx->sched_tags;
unsigned int shift = tags->bitmap_tags.sb.shift;
dd->async_depth = max(1U, 3 * (1U << shift) / 4);
dd->async_depth = max(1UL, 3 * q->nr_requests / 4);
sbitmap_queue_min_shallow_depth(&tags->bitmap_tags, dd->async_depth);
}