From: Keith Busch <kbusch@kernel.org>
To: Kanchan Joshi <joshi.k@samsung.com>
Cc: axboe@kernel.dk, hch@lst.de, chaitanya.kulkarni@wdc.com,
io-uring@vger.kernel.org, linux-nvme@lists.infradead.org,
anuj20.g@samsung.com, javier.gonz@samsung.com,
nj.shetty@samsung.com, selvakuma.s1@samsung.com
Subject: Re: [RFC PATCH v3 2/3] nvme: keep nvme_command instead of pointer to it
Date: Tue, 16 Mar 2021 10:16:28 -0700 [thread overview]
Message-ID: <20210316171628.GA4161119@dhcp-10-100-145-180.wdc.com> (raw)
In-Reply-To: <20210316140126.24900-3-joshi.k@samsung.com>
On Tue, Mar 16, 2021 at 07:31:25PM +0530, Kanchan Joshi wrote:
> nvme_req structure originally contained a pointer to nvme_command.
> Change nvme_req structure to keep the command itself.
> This helps in avoiding hot-path memory-allocation for async-passthrough.
I have a slightly different take on how to handle pre-allocated
passthrough commands. Every transport except PCI already preallocates a
'struct nvme_command' within the pdu, so allocating another one looks
redundant. Also, it does consume quite a bit of memory for something
that is used only for the passthrough case.
I think we can solve both concerns by always using the PDU nvme_command
rather than have the transport drivers provide it. I just sent the patch
here if you can take a look. It tested fine on PCI and loop (haven't
tested any other transports).
http://lists.infradead.org/pipermail/linux-nvme/2021-March/023711.html
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next prev parent reply other threads:[~2021-03-16 17:16 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210316140229epcas5p23d68a4c9694bbf7759b5901115a4309b@epcas5p2.samsung.com>
2021-03-16 14:01 ` [RFC PATCH v3 0/3] Async nvme passthrough over io_uring Kanchan Joshi
[not found] ` <CGME20210316140233epcas5p372405e7cb302c61dba5e1094fa796513@epcas5p3.samsung.com>
2021-03-16 14:01 ` [RFC PATCH v3 1/3] io_uring: add helper for uring_cmd completion in submitter-task Kanchan Joshi
2021-03-16 15:43 ` Stefan Metzmacher
2021-03-18 1:57 ` Jens Axboe
2021-03-18 5:25 ` Kanchan Joshi
2021-03-18 5:48 ` Christoph Hellwig
2021-03-18 6:14 ` Kanchan Joshi
[not found] ` <CGME20210316140236epcas5p4de087ee51a862402146fbbc621d4d4c6@epcas5p4.samsung.com>
2021-03-16 14:01 ` [RFC PATCH v3 2/3] nvme: keep nvme_command instead of pointer to it Kanchan Joshi
2021-03-16 17:16 ` Keith Busch [this message]
2021-03-17 9:38 ` Kanchan Joshi
2021-03-17 14:17 ` Keith Busch
[not found] ` <CGME20210316140240epcas5p3e71bfe2afecd728c5af60056f21cc9b7@epcas5p3.samsung.com>
2021-03-16 14:01 ` [RFC PATCH v3 3/3] nvme: wire up support for async passthrough Kanchan Joshi
2021-03-17 8:52 ` Christoph Hellwig
2021-03-17 16:49 ` Jens Axboe
2021-03-17 16:59 ` Christoph Hellwig
2021-03-17 17:21 ` Jens Axboe
2021-03-17 18:59 ` Jens Axboe
2021-03-18 5:54 ` Kanchan Joshi
2021-03-17 16:45 ` Keith Busch
2021-03-17 17:02 ` Christoph Hellwig
2021-03-16 15:51 ` [RFC PATCH v3 0/3] Async nvme passthrough over io_uring Jens Axboe
2021-03-17 9:31 ` Kanchan Joshi
2021-03-18 1:58 ` Jens Axboe
2021-03-18 7:47 ` Kanchan Joshi
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