Re: [PATCH] blk-mq: only run mapped hw queues in blk_mq_run_hw_queues()
From: Jens Axboe <axboe@kernel.dk>
Date: 2018-03-28 14:38:59
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
On 3/28/18 1:45 AM, Christian Borntraeger wrote:
FWIW, this patch does not fix the issue for me:
Looks like I didn't do the delayed path. How about the below?
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 16e83e6df404..fd663ae1094c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c@@ -1302,10 +1302,23 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, return (queued + errors) != 0; } +static bool blk_mq_bail_unmapped(struct blk_mq_hw_ctx *hctx) +{ + /* + * Warn if the queue isn't mapped AND we have pending IO. Not being + * mapped isn't necessarily a huge issue, if we don't have pending IO. + */ + return !blk_mq_hw_queue_mapped(hctx) && + !WARN_ON_ONCE(blk_mq_hctx_has_pending(hctx)); +} + static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) { int srcu_idx; + if (blk_mq_bail_unmapped(hctx)) + return; + /* * We should be running this queue from one of the CPUs that * are mapped to it.
@@ -1399,9 +1412,8 @@ static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, unsigned long msecs) { - if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx))) + if (blk_mq_bail_unmapped(hctx)) return; - if (unlikely(blk_mq_hctx_stopped(hctx))) return;
--
Jens Axboe