From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Hannes Reinecke <hare@suse.de>, Sagi Grimberg <sagi@grimberg.me>,
Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
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 17:19:39 +0100 [thread overview]
Message-ID: <20210323161939.GC13402@lst.de> (raw)
In-Reply-To: <20210323145330.GB21687@redsun51.ssa.fujisawa.hgst.com>
On Tue, Mar 23, 2021 at 11:53:30PM +0900, Keith Busch wrote:
> Failover might be overkill. We can run out of tags in a perfectly normal
> situation, and simply waiting may be the best option, or even scheduling
> on a different CPU may be sufficient to get a viable tag rather than
> selecting a different path.
Indeed. Then again IFF there are multiple optimized paths picking one
could also be a way to make progress.
> Does it make sense to just abort all allocated tags during a reset and
> let the original bio requeue for multipath IO?
Well, this would again hard code multipath information into the lower
levels. But then again we could at least do it so that we check for
the REQ_NVME_MPATH to make it clear what is going on.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Hannes Reinecke <hare@suse.de>, Sagi Grimberg <sagi@grimberg.me>,
Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
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 17:19:39 +0100 [thread overview]
Message-ID: <20210323161939.GC13402@lst.de> (raw)
In-Reply-To: <20210323145330.GB21687@redsun51.ssa.fujisawa.hgst.com>
On Tue, Mar 23, 2021 at 11:53:30PM +0900, Keith Busch wrote:
> Failover might be overkill. We can run out of tags in a perfectly normal
> situation, and simply waiting may be the best option, or even scheduling
> on a different CPU may be sufficient to get a viable tag rather than
> selecting a different path.
Indeed. Then again IFF there are multiple optimized paths picking one
could also be a way to make progress.
> Does it make sense to just abort all allocated tags during a reset and
> let the original bio requeue for multipath IO?
Well, this would again hard code multipath information into the lower
levels. But then again we could at least do it so that we check for
the REQ_NVME_MPATH to make it clear what is going on.
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Linux-nvme@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-nvme
next prev parent reply other threads:[~2021-03-23 16:20 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
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 [this message]
2021-03-23 16:19 ` Christoph Hellwig
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