From: Christoph Hellwig <hch@lst.de>
To: Sagi Grimberg <sagi@grimberg.me>
Cc: linux-nvme@lists.infradead.org, Christoph Hellwig <hch@lst.de>,
Keith Busch <kbusch@kernel.org>,
Chaitanya Kulkarni <kch@nvidia.com>,
Daniel Wagner <dwagner@suse.de>,
Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>,
Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH 4/6] nvme-mpath: support controller crd when failing over request
Date: Wed, 2 Sep 2026 15:43:00 +0200 [thread overview]
Message-ID: <20260902134300.GD21649@lst.de> (raw)
In-Reply-To: <20260823084903.193188-5-sagi@grimberg.me>
On Sun, Aug 23, 2026 at 11:49:00AM +0300, Sagi Grimberg wrote:
> When failing over a request (due to a path based status) we should
> repect controller crd returned in the nvme completion as much as
> possible. Hence we want to delay the failover command execution by
> the controller crdt.
>
> We allocate a new nvme_mpath_failover_timer referencing the request
> stolen bios in a staging list, and when the command retry delay expires,
> and only then the bios are moved to the mpath head requeue list which is
> immediately kicked to re-submit these bios. If we failed to allocate
> a fot, we fallback to the existing behavior.
>
> Given that we now have a new staging list for mpath devices, we drain
> them when removing the device.
Given that we only have a few potential CRD levels, what about having
the "container" for the requing statically preallocated for each?
next prev parent reply other threads:[~2026-09-02 13:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-23 8:48 [PATCH 0/6] Support per command retry timer Sagi Grimberg
2026-08-23 8:48 ` [PATCH 1/6] nvme-mpath: No need to protect req->bio with requeue_lock Sagi Grimberg
2026-08-24 11:31 ` Hannes Reinecke
2026-08-24 15:53 ` John Garry
2026-09-02 13:39 ` Christoph Hellwig
2026-08-23 8:48 ` [PATCH 2/6] nvme: add nvme_crd_msecs helper Sagi Grimberg
2026-08-24 11:32 ` Hannes Reinecke
2026-09-02 13:40 ` Christoph Hellwig
2026-09-06 0:07 ` Sagi Grimberg
2026-08-23 8:48 ` [PATCH 3/6] nvme: add per request retry timer Sagi Grimberg
2026-08-24 13:25 ` Hannes Reinecke
2026-09-02 13:41 ` Christoph Hellwig
2026-09-06 0:09 ` Sagi Grimberg
2026-09-11 22:53 ` Sagi Grimberg
2026-08-23 8:49 ` [PATCH 4/6] nvme-mpath: support controller crd when failing over request Sagi Grimberg
2026-08-24 13:45 ` Hannes Reinecke
2026-08-24 14:23 ` Sagi Grimberg
2026-09-02 13:43 ` Christoph Hellwig [this message]
2026-09-06 0:15 ` Sagi Grimberg
2026-08-23 8:49 ` [PATCH 5/6] nvmet: Add support for configurable crdt (command retry delay) attributes Sagi Grimberg
2026-09-02 13:44 ` Christoph Hellwig
2026-09-06 0:20 ` Sagi Grimberg
2026-08-23 8:49 ` [PATCH 6/6] nvme/fault-injection: Support for error injection with custom crd Sagi Grimberg
2026-08-23 8:49 ` [PATCH 7/6 RFC] nvme: test per-command retry delay Sagi Grimberg
2026-08-30 8:23 ` Shin'ichiro Kawasaki
2026-08-30 20:55 ` Sagi Grimberg
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