From: Bart Van Assche <Bart.VanAssche@wdc.com>
To: "hch@lst.de" <hch@lst.de>
Cc: "keith.busch@intel.com" <keith.busch@intel.com>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"sagi@grimberg.me" <sagi@grimberg.me>
Subject: Re: [PATCH 10/10] nvme: implement multipath access to nvme subsystems
Date: Thu, 24 Aug 2017 20:17:32 +0000 [thread overview]
Message-ID: <1503605798.2899.43.camel@wdc.com> (raw)
In-Reply-To: <20170824085954.GD19504@lst.de>
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WARNING: multiple messages have this Message-ID (diff)
From: Bart.VanAssche@wdc.com (Bart Van Assche)
Subject: [PATCH 10/10] nvme: implement multipath access to nvme subsystems
Date: Thu, 24 Aug 2017 20:17:32 +0000 [thread overview]
Message-ID: <1503605798.2899.43.camel@wdc.com> (raw)
In-Reply-To: <20170824085954.GD19504@lst.de>
On Thu, 2017-08-24@10:59 +0200, hch@lst.de wrote:
> On Wed, Aug 23, 2017@06:21:55PM +0000, Bart Van Assche wrote:
> > Since generic_make_request_fast() returns BLK_STS_AGAIN for a dying path:
> > can the same kind of soft lockups occur with the NVMe multipathing code as
> > with the current upstream device mapper multipathing code? See e.g.
> > "[PATCH 3/7] dm-mpath: Do not lock up a CPU with requeuing activity"
> > (https://www.redhat.com/archives/dm-devel/2017-August/msg00124.html).
>
> I suspect the code is not going to hit it because we check the controller
> state before trying to queue I/O on the lower queue. But if you point
> me to a good reproducer test case I'd like to check.
For NVMe over RDMA, how about the simulate_network_failure_loop() function in
https://github.com/bvanassche/srp-test/blob/master/lib/functions? It simulates
a network failure by writing into the reset_controller sysfs attribute.
> Also does the "single queue" case in your mail refer to the old
> request code? nvme only uses blk-mq so it would not hit that.
> But either way I think get_request should be fixed to return
> BLK_STS_IOERR if the queue is dying instead of BLK_STS_AGAIN.
The description in the patch I referred to indeed refers to the old request
code in the block layer. When I prepared that patch I had analyzed the
behavior of the old request code only.
Bart.
next prev parent reply other threads:[~2017-08-24 20:17 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-23 17:58 RFC: nvme multipath support Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-23 17:58 ` [PATCH 01/10] nvme: report more detailed status codes to the block layer Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 6:06 ` Sagi Grimberg
2017-08-28 6:06 ` Sagi Grimberg
2017-08-28 18:50 ` Keith Busch
2017-08-28 18:50 ` Keith Busch
2017-08-23 17:58 ` [PATCH 02/10] nvme: allow calling nvme_change_ctrl_state from irq context Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 6:06 ` Sagi Grimberg
2017-08-28 6:06 ` Sagi Grimberg
2017-08-28 18:50 ` Keith Busch
2017-08-28 18:50 ` Keith Busch
2017-08-23 17:58 ` [PATCH 03/10] nvme: remove unused struct nvme_ns fields Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 6:07 ` Sagi Grimberg
2017-08-28 6:07 ` Sagi Grimberg
2017-08-28 19:13 ` Keith Busch
2017-08-28 19:13 ` Keith Busch
2017-08-23 17:58 ` [PATCH 04/10] nvme: remove nvme_revalidate_ns Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 6:12 ` Sagi Grimberg
2017-08-28 6:12 ` Sagi Grimberg
2017-08-28 19:14 ` Keith Busch
2017-08-28 19:14 ` Keith Busch
2017-08-23 17:58 ` [PATCH 05/10] nvme: don't blindly overwrite identifiers on disk revalidate Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 6:17 ` Sagi Grimberg
2017-08-28 6:17 ` Sagi Grimberg
2017-08-28 6:23 ` Christoph Hellwig
2017-08-28 6:23 ` Christoph Hellwig
2017-08-28 6:32 ` Sagi Grimberg
2017-08-28 6:32 ` Sagi Grimberg
2017-08-28 19:15 ` Keith Busch
2017-08-28 19:15 ` Keith Busch
2017-08-23 17:58 ` [PATCH 06/10] nvme: track subsystems Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-23 22:04 ` Keith Busch
2017-08-23 22:04 ` Keith Busch
2017-08-24 8:52 ` Christoph Hellwig
2017-08-24 8:52 ` Christoph Hellwig
2017-08-28 6:22 ` Sagi Grimberg
2017-08-28 6:22 ` Sagi Grimberg
2017-08-23 17:58 ` [PATCH 07/10] nvme: track shared namespaces Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 6:51 ` Sagi Grimberg
2017-08-28 6:51 ` Sagi Grimberg
2017-08-28 8:50 ` Christoph Hellwig
2017-08-28 8:50 ` Christoph Hellwig
2017-08-28 20:21 ` J Freyensee
2017-08-28 20:21 ` J Freyensee
2017-08-29 8:25 ` Christoph Hellwig
2017-08-29 8:25 ` Christoph Hellwig
2017-08-29 6:54 ` Guan Junxiong
2017-08-29 6:54 ` Guan Junxiong
2017-08-28 12:04 ` javigon
2017-08-28 12:04 ` javigon
2017-08-28 12:41 ` Guan Junxiong
2017-08-28 12:41 ` Guan Junxiong
2017-08-28 14:30 ` Christoph Hellwig
2017-08-28 14:30 ` Christoph Hellwig
2017-08-29 2:42 ` Guan Junxiong
2017-08-29 2:42 ` Guan Junxiong
2017-08-29 8:30 ` Christoph Hellwig
2017-08-29 8:30 ` Christoph Hellwig
2017-08-29 8:29 ` Christoph Hellwig
2017-08-29 8:29 ` Christoph Hellwig
2017-08-28 19:18 ` Keith Busch
2017-08-28 19:18 ` Keith Busch
2017-08-23 17:58 ` [PATCH 08/10] block: provide a generic_make_request_fast helper Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 7:00 ` Sagi Grimberg
2017-08-28 7:00 ` Sagi Grimberg
2017-08-28 8:54 ` Christoph Hellwig
2017-08-28 8:54 ` Christoph Hellwig
2017-08-28 11:01 ` Sagi Grimberg
2017-08-28 11:01 ` Sagi Grimberg
2017-08-28 11:54 ` Christoph Hellwig
2017-08-28 11:54 ` Christoph Hellwig
2017-08-28 12:38 ` Sagi Grimberg
2017-08-28 12:38 ` Sagi Grimberg
2017-08-23 17:58 ` [PATCH 09/10] blk-mq: add a blk_steal_bios helper Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-28 7:04 ` Sagi Grimberg
2017-08-28 7:04 ` Sagi Grimberg
2017-08-23 17:58 ` [PATCH 10/10] nvme: implement multipath access to nvme subsystems Christoph Hellwig
2017-08-23 17:58 ` Christoph Hellwig
2017-08-23 18:21 ` Bart Van Assche
2017-08-23 18:21 ` Bart Van Assche
2017-08-24 8:59 ` hch
2017-08-24 8:59 ` hch
2017-08-24 20:17 ` Bart Van Assche [this message]
2017-08-24 20:17 ` Bart Van Assche
2017-09-05 11:53 ` Christoph Hellwig
2017-09-05 11:53 ` Christoph Hellwig
2017-09-11 6:34 ` Tony Yang
2017-08-23 22:53 ` Keith Busch
2017-08-23 22:53 ` Keith Busch
2017-08-24 8:52 ` Christoph Hellwig
2017-08-24 8:52 ` Christoph Hellwig
2017-08-28 7:23 ` Sagi Grimberg
2017-08-28 7:23 ` Sagi Grimberg
2017-08-28 9:06 ` Christoph Hellwig
2017-08-28 9:06 ` Christoph Hellwig
2017-08-28 13:40 ` Sagi Grimberg
2017-08-28 13:40 ` Sagi Grimberg
2017-08-28 14:24 ` Christoph Hellwig
2017-08-28 14:24 ` Christoph Hellwig
2017-09-07 15:17 ` Tony Yang
2017-08-29 10:22 ` Guan Junxiong
2017-08-29 10:22 ` Guan Junxiong
2017-08-29 14:51 ` Christoph Hellwig
2017-08-29 14:51 ` Christoph Hellwig
2017-08-29 14:54 ` Keith Busch
2017-08-29 14:54 ` Keith Busch
2017-08-29 14:55 ` Christoph Hellwig
2017-08-29 14:55 ` Christoph Hellwig
2017-08-29 15:41 ` Keith Busch
2017-08-29 15:41 ` Keith Busch
2017-09-18 0:17 ` Christoph Hellwig
2017-09-18 0:17 ` Christoph Hellwig
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