From 9f87fc4d72f52b26ac3e19df5e4584227fe6740c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 14 Jul 2023 16:30:14 +0200 Subject: block: queue data commands from the flush state machine at the head We used to insert the data commands following a pre-flush to the head of the queue until commit 1e82fadfc6b ("blk-mq: do not do head insertions post-pre-flush commands"). Not doing this seems to cause hangs of such commands on NFS workloads when exported from file systems with SATA SSDs. I have no idea why this would starve these workloads, but doing a semantic revert of this patch (which looks quite different due to various other changes) fixes the hangs. Fixes: 1e82fadfc6b ("blk-mq: do not do head insertions post-pre-flush commands") Reported-by: Chuck Lever Signed-off-by: Christoph Hellwig Tested-by: Chuck Lever Link: https://lore.kernel.org/r/20230714143014.11879-1-hch@lst.de Signed-off-by: Jens Axboe --- block/blk-flush.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block/blk-flush.c') diff --git a/block/blk-flush.c b/block/blk-flush.c index dba392cf22be..8220517c2d67 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -189,7 +189,7 @@ static void blk_flush_complete_seq(struct request *rq, case REQ_FSEQ_DATA: list_move_tail(&rq->flush.list, &fq->flush_data_in_flight); spin_lock(&q->requeue_lock); - list_add_tail(&rq->queuelist, &q->flush_list); + list_add(&rq->queuelist, &q->requeue_list); spin_unlock(&q->requeue_lock); blk_mq_kick_requeue_list(q); break; -- cgit