From: Eric Blake <eblake@redhat.com>
To: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
qemu-devel@nongnu.org, qemu-block@nongnu.org
Cc: kwolf@redhat.com, fam@euphon.net, mreitz@redhat.com,
stefanha@redhat.com, den@openvz.org, jsnow@redhat.com
Subject: Re: [Qemu-devel] [PATCH v3 3/3] nbd: improve CMD_CACHE: use BDRV_REQ_PREFETCH
Date: Mon, 29 Jul 2019 16:24:39 -0500 [thread overview]
Message-ID: <cf6ad0f9-1e4c-9f8a-ab0c-512beaeba53b@redhat.com> (raw)
In-Reply-To: <20190725100550.33801-4-vsementsov@virtuozzo.com>
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On 7/25/19 5:05 AM, Vladimir Sementsov-Ogievskiy wrote:
> This helps to avoid extra io, allocations and memory copying.
> We assume here that CMD_CACHE is always used with copy-on-read, as
> otherwise it's a noop.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> nbd/server.c | 43 +++++++++++++++++++++++++++++++++++--------
> 1 file changed, 35 insertions(+), 8 deletions(-)
libnbd is able to test NBD_CMD_CACHE requests, and I've confirmed that
behavior looks sane under requests issued that way. I'm wondering if
qemu-io should also be able to drive this mode of operation, so that we
can give it iotest coverage without depending on libnbd.
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
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next prev parent reply other threads:[~2019-07-29 21:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 10:05 [Qemu-devel] [PATCH v3 for-4.2 0/3] block: BDRV_REQ_PREFETCH Vladimir Sementsov-Ogievskiy
2019-07-25 10:05 ` [Qemu-devel] [PATCH v3 1/3] block: implement BDRV_REQ_PREFETCH Vladimir Sementsov-Ogievskiy
2019-07-29 21:13 ` Eric Blake
2019-07-25 10:05 ` [Qemu-devel] [PATCH v3 2/3] block/stream: use BDRV_REQ_PREFETCH Vladimir Sementsov-Ogievskiy
2019-07-29 21:19 ` Eric Blake
2019-07-25 10:05 ` [Qemu-devel] [PATCH v3 3/3] nbd: improve CMD_CACHE: " Vladimir Sementsov-Ogievskiy
2019-07-29 21:24 ` Eric Blake [this message]
2019-07-29 15:00 ` [Qemu-devel] [Qemu-block] [PATCH v3 for-4.2 0/3] block: BDRV_REQ_PREFETCH Stefan Hajnoczi
2019-07-29 15:29 ` Vladimir Sementsov-Ogievskiy
2019-07-29 15:38 ` Eric Blake
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