From: Sagi Grimberg <sagi@grimberg.me>
To: Hannes Reinecke <hare@suse.de>, Christoph Hellwig <hch@lst.de>,
Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@kernel.dk>
Cc: Chao Leng <lengchao@huawei.com>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: [PATCH 2/2] nvme-multipath: don't block on blk_queue_enter of the underlying device
Date: Tue, 23 Mar 2021 00:31:32 -0700 [thread overview]
Message-ID: <608f8198-8c0d-b59c-180b-51666840382d@grimberg.me> (raw)
In-Reply-To: <c064b296-c25c-3731-cbbd-f99ab93e6bd2@suse.de>
> Actually, I had been playing around with marking the entire bio as
> 'NOWAIT'; that would avoid the tag stall, too:
>
> @@ -313,7 +316,7 @@ blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
> ns = nvme_find_path(head);
> if (likely(ns)) {
> bio_set_dev(bio, ns->disk->part0);
> - bio->bi_opf |= REQ_NVME_MPATH;
> + bio->bi_opf |= REQ_NVME_MPATH | REQ_NOWAIT;
> trace_block_bio_remap(bio, disk_devt(ns->head->disk),
> bio->bi_iter.bi_sector);
> ret = submit_bio_noacct(bio);
>
>
> My only worry here is that we might incur spurious failures under high
> load; but then this is not necessarily a bad thing.
What? making spurious failures is not ok under any load. what fs will
take into account that you may have run out of tags?
WARNING: multiple messages have this Message-ID (diff)
From: Sagi Grimberg <sagi@grimberg.me>
To: Hannes Reinecke <hare@suse.de>, Christoph Hellwig <hch@lst.de>,
Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@kernel.dk>
Cc: Chao Leng <lengchao@huawei.com>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org
Subject: Re: [PATCH 2/2] nvme-multipath: don't block on blk_queue_enter of the underlying device
Date: Tue, 23 Mar 2021 00:31:32 -0700 [thread overview]
Message-ID: <608f8198-8c0d-b59c-180b-51666840382d@grimberg.me> (raw)
In-Reply-To: <c064b296-c25c-3731-cbbd-f99ab93e6bd2@suse.de>
> Actually, I had been playing around with marking the entire bio as
> 'NOWAIT'; that would avoid the tag stall, too:
>
> @@ -313,7 +316,7 @@ blk_qc_t nvme_ns_head_submit_bio(struct bio *bio)
> ns = nvme_find_path(head);
> if (likely(ns)) {
> bio_set_dev(bio, ns->disk->part0);
> - bio->bi_opf |= REQ_NVME_MPATH;
> + bio->bi_opf |= REQ_NVME_MPATH | REQ_NOWAIT;
> trace_block_bio_remap(bio, disk_devt(ns->head->disk),
> bio->bi_iter.bi_sector);
> ret = submit_bio_noacct(bio);
>
>
> My only worry here is that we might incur spurious failures under high
> load; but then this is not necessarily a bad thing.
What? making spurious failures is not ok under any load. what fs will
take into account that you may have run out of tags?
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next prev parent reply other threads:[~2021-03-23 7:32 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 7:37 fix nvme-tcp and nvme-rdma controller reset hangs when using multipath Christoph Hellwig
2021-03-22 7:37 ` Christoph Hellwig
2021-03-22 7:37 ` [PATCH 1/2] blk-mq: add a blk_mq_submit_bio_direct API Christoph Hellwig
2021-03-22 7:37 ` Christoph Hellwig
2021-03-22 11:23 ` Hannes Reinecke
2021-03-22 11:23 ` Hannes Reinecke
2021-03-22 15:30 ` Keith Busch
2021-03-22 15:30 ` Keith Busch
2021-03-22 7:37 ` [PATCH 2/2] nvme-multipath: don't block on blk_queue_enter of the underlying device Christoph Hellwig
2021-03-22 7:37 ` Christoph Hellwig
2021-03-22 11:22 ` Hannes Reinecke
2021-03-22 11:22 ` Hannes Reinecke
2021-03-22 15:31 ` Keith Busch
2021-03-22 15:31 ` Keith Busch
2021-03-23 2:57 ` Sagi Grimberg
2021-03-23 2:57 ` Sagi Grimberg
2021-03-23 3:23 ` Sagi Grimberg
2021-03-23 3:23 ` Sagi Grimberg
2021-03-23 7:04 ` Chao Leng
2021-03-23 7:04 ` Chao Leng
2021-03-23 7:36 ` Sagi Grimberg
2021-03-23 7:36 ` Sagi Grimberg
2021-03-23 8:13 ` Chao Leng
2021-03-23 8:13 ` Chao Leng
2021-03-23 16:17 ` Christoph Hellwig
2021-03-23 16:17 ` Christoph Hellwig
2021-03-23 16:15 ` Christoph Hellwig
2021-03-23 16:15 ` Christoph Hellwig
2021-03-23 18:13 ` Sagi Grimberg
2021-03-23 18:13 ` Sagi Grimberg
2021-03-23 18:22 ` Christoph Hellwig
2021-03-23 18:22 ` Christoph Hellwig
2021-03-23 19:00 ` Sagi Grimberg
2021-03-23 19:00 ` Sagi Grimberg
2021-03-23 19:01 ` Christoph Hellwig
2021-03-23 19:01 ` Christoph Hellwig
2021-03-23 19:10 ` Sagi Grimberg
2021-03-23 19:10 ` Sagi Grimberg
2021-03-23 7:28 ` Hannes Reinecke
2021-03-23 7:28 ` Hannes Reinecke
2021-03-23 7:31 ` Sagi Grimberg [this message]
2021-03-23 7:31 ` Sagi Grimberg
2021-03-23 8:36 ` Hannes Reinecke
2021-03-23 8:36 ` Hannes Reinecke
2021-03-23 14:53 ` Keith Busch
2021-03-23 14:53 ` Keith Busch
2021-03-23 16:19 ` Christoph Hellwig
2021-03-23 16:19 ` Christoph Hellwig
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