From: Jens Axboe <axboe@kernel.dk>
To: Sagi Grimberg <sagi@grimberg.me>, linux-nvme@lists.infradead.org
Cc: Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@kernel.org>,
Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
Hannes Reinecke <hare@suse.de>,
linux-block@vger.kernel.org
Subject: Re: [PATCH v2 2/2] nvme: support io stats on the mpath device
Date: Tue, 29 Nov 2022 07:33:51 -0700 [thread overview]
Message-ID: <9f45de57-353a-08c9-5d7f-57d7acc67b18@kernel.dk> (raw)
In-Reply-To: <20221003094344.242593-3-sagi@grimberg.me>
On 10/3/22 3:43 AM, Sagi Grimberg wrote:
> Our mpath stack device is just a shim that selects a bottom namespace
> and submits the bio to it without any fancy splitting. This also means
> that we don't clone the bio or have any context to the bio beyond
> submission. However it really sucks that we don't see the mpath device
> io stats.
>
> Given that the mpath device can't do that without adding some context
> to it, we let the bottom device do it on its behalf (somewhat similar
> to the approach taken in nvme_trace_bio_complete).
>
> When the IO starts, we account the request for multipath IO stats using
> REQ_NVME_MPATH_IO_STATS nvme_request flag to avoid queue io stats disable
> in the middle of the request.
Reviewed-by: Jens Axboe <axboe@kernel.dk>
--
Jens Axboe
next prev parent reply other threads:[~2022-11-29 14:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-03 9:43 [PATCH v2 0/2] nvme-mpath: Add IO stats support Sagi Grimberg
2022-10-03 9:43 ` [PATCH v2 1/2] nvme: introduce nvme_start_request Sagi Grimberg
2022-10-04 6:09 ` Hannes Reinecke
2022-11-29 14:28 ` Keith Busch
2022-11-29 14:32 ` Jens Axboe
2022-11-29 14:31 ` Jens Axboe
2022-10-03 9:43 ` [PATCH v2 2/2] nvme: support io stats on the mpath device Sagi Grimberg
2022-10-04 6:11 ` Hannes Reinecke
2022-10-04 8:19 ` Sagi Grimberg
2022-11-29 14:33 ` Jens Axboe
2022-11-29 14:33 ` Jens Axboe [this message]
2022-11-29 14:42 ` Keith Busch
2022-11-29 14:45 ` [PATCH v2 0/2] nvme-mpath: Add IO stats support Christoph Hellwig
2022-11-29 16:43 ` Keith Busch
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