From: Stefan Hajnoczi <stefanha@redhat.com>
To: Klaus Jensen <its@irrelevant.dk>
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <fam@euphon.net>,
qemu-block@nongnu.org, Klaus Jensen <k.jensen@samsung.com>,
qemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>,
Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH RFC v5 12/12] hw/block/nvme: add persistence for zone info
Date: Mon, 30 Nov 2020 12:33:00 +0000 [thread overview]
Message-ID: <20201130123300.GA422962@stefanha-x1.localdomain> (raw)
In-Reply-To: <20201126234601.689714-13-its@irrelevant.dk>
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On Fri, Nov 27, 2020 at 12:46:01AM +0100, Klaus Jensen wrote:
> From: Klaus Jensen <k.jensen@samsung.com>
>
> Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
> ---
> docs/specs/nvme.txt | 15 +++
> hw/block/nvme-ns.h | 16 ++++
> hw/block/nvme-ns.c | 212 +++++++++++++++++++++++++++++++++++++++++-
> hw/block/nvme.c | 87 +++++++++++++++++
> hw/block/trace-events | 2 +
> 5 files changed, 331 insertions(+), 1 deletion(-)
>
> diff --git a/docs/specs/nvme.txt b/docs/specs/nvme.txt
> index 03bb4d9516b4..05d81c88ad4e 100644
> --- a/docs/specs/nvme.txt
> +++ b/docs/specs/nvme.txt
> @@ -20,6 +20,21 @@ The nvme device (-device nvme) emulates an NVM Express Controller.
> `zns.mor`; Specifies the number of open resources available. This is a 0s
> based value.
>
> + `zns.pstate`; This parameter specifies another blockdev to be used for
> + storing zone state persistently.
> +
> + -drive id=zns-pstate,file=zns-pstate.img,format=raw
> + -device nvme-ns,zns.pstate=zns-pstate,...
> +
> + To reset (or initialize) state, the blockdev image should be of zero size:
> +
> + qemu-img create -f raw zns-pstate.img 0
> +
> + The image will be intialized with a file format header and truncated to
> + the required size. If the pstate given is of non-zero size, it will be
> + assumed to already contain zone state information and the header will be
> + checked.
In principle this makes sense but at first glance it looks like the code
is synchronous - it blocks the vCPU if zone metadata I/O is necessary.
That works for test/bring-up code but can't be used in production due to
the performance impact.
Is the expectation that the QEMU NVMe device emulation will only be used
for test/bring-up now and in the future?
Stefan
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next prev parent reply other threads:[~2020-11-30 12:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-26 23:45 [PATCH v5 00/12] hw/block/nvme: zoned namespace command set Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 01/12] hw/block/nvme: Separate read and write handlers Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 02/12] hw/block/nvme: Merge nvme_write_zeroes() with nvme_write() Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 03/12] hw/block/nvme: add commands supported and effects log page Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 04/12] hw/block/nvme: Generate namespace UUIDs Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 05/12] hw/block/nvme: support namespace types Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 06/12] hw/block/nvme: add basic read/write for zoned namespaces Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 07/12] hw/block/nvme: add the zone management receive command Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 08/12] hw/block/nvme: add the zone management send command Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 09/12] hw/block/nvme: add the zone append command Klaus Jensen
2020-11-26 23:45 ` [PATCH v5 10/12] hw/block/nvme: track and enforce zone resources Klaus Jensen
2020-11-26 23:46 ` [PATCH v5 11/12] hw/block/nvme: allow open to close zone transitions by controller Klaus Jensen
2020-11-26 23:46 ` [PATCH RFC v5 12/12] hw/block/nvme: add persistence for zone info Klaus Jensen
2020-11-30 12:33 ` Stefan Hajnoczi [this message]
2020-11-30 12:59 ` Klaus Jensen
2020-11-30 13:18 ` Klaus Jensen
2020-11-30 14:58 ` Stefan Hajnoczi
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