From: Paolo Bonzini <pbonzini@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 06/12] nbd: support NBD_CMD_TRIM in the server
Date: Wed, 14 Sep 2011 18:25:59 +0200 [thread overview]
Message-ID: <4E70D597.2040405@redhat.com> (raw)
In-Reply-To: <20110914154422.GA13438@lst.de>
On 09/14/2011 05:44 PM, Christoph Hellwig wrote:
>> Map it to bdrv_discard. The server can now expose NBD_FLAG_SEND_TRIM.
>
> Note that discard support without a way to communicate the alignment/size
> requirements,
Yep, especially because alignment can be as small as 512 for sparse raw,
and as high as 65536 for qcow2...
> and without the discard_zeroes_data flag is pretty much
> useless.
... but right now in QEMU it is most useful with qcow2, so
!discard_zeroes_data is pretty much the best you can do.
In general, QEMU's block layer does not really do much to pass
information on discard features, which is why I didn't think much about
these bits. I'm interested in making NBD as featureful as the QEMU
block layer, but beyond that not much. :)
Still you're obviously right, I'll talk to upstream.
Paolo
next prev parent reply other threads:[~2011-09-14 16:26 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-08 15:24 [Qemu-devel] [PATCH 00/12] nbd improvements Paolo Bonzini
2011-09-08 15:24 ` [Qemu-devel] [PATCH 01/12] nbd: support feature negotiation Paolo Bonzini
2011-09-08 15:24 ` [Qemu-devel] [PATCH 02/12] nbd: sync API definitions with upstream Paolo Bonzini
2011-09-12 14:15 ` Kevin Wolf
2011-09-12 15:08 ` Paolo Bonzini
2011-09-08 15:24 ` [Qemu-devel] [PATCH 03/12] nbd: support NBD_SET_FLAGS ioctl Paolo Bonzini
2011-09-08 15:24 ` [Qemu-devel] [PATCH 04/12] nbd: add support for NBD_CMD_FLUSH Paolo Bonzini
2011-09-13 13:52 ` Kevin Wolf
2011-09-13 15:13 ` Paolo Bonzini
2011-09-08 15:24 ` [Qemu-devel] [PATCH 05/12] nbd: add support for NBD_CMD_FLAG_FUA Paolo Bonzini
2011-09-13 13:55 ` Kevin Wolf
2011-09-08 15:24 ` [Qemu-devel] [PATCH 06/12] nbd: support NBD_CMD_TRIM in the server Paolo Bonzini
2011-09-13 13:58 ` Kevin Wolf
2011-09-13 15:14 ` Paolo Bonzini
2011-09-14 15:44 ` Christoph Hellwig
2011-09-14 16:25 ` Paolo Bonzini [this message]
2011-09-08 15:25 ` [Qemu-devel] [PATCH 07/12] sheepdog: add coroutine_fn markers Paolo Bonzini
2011-09-08 15:25 ` [Qemu-devel] [PATCH 08/12] add socket_set_block Paolo Bonzini
2011-09-08 15:25 ` [Qemu-devel] [PATCH 09/12] sheepdog: move coroutine send/recv function to generic code Paolo Bonzini
2011-09-09 4:53 ` MORITA Kazutaka
2011-09-09 8:11 ` [Qemu-devel] [PATCH v2 " Paolo Bonzini
2011-09-13 0:28 ` MORITA Kazutaka
2011-09-13 14:14 ` Kevin Wolf
2011-09-13 15:16 ` Paolo Bonzini
2011-09-13 15:36 ` Kevin Wolf
2011-09-13 15:38 ` Paolo Bonzini
2011-09-08 15:25 ` [Qemu-devel] [PATCH 10/12] block: add bdrv_co_flush support Paolo Bonzini
2011-09-08 15:25 ` [Qemu-devel] [PATCH 11/12] nbd: switch to asynchronous operation Paolo Bonzini
2011-09-09 14:52 ` Nicholas Thomas
2011-09-09 15:03 ` Paolo Bonzini
2011-09-09 15:34 ` Paolo Bonzini
2011-09-08 15:25 ` [Qemu-devel] [PATCH 12/12] nbd: split requests Paolo Bonzini
2011-09-09 14:52 ` Nicholas Thomas
2011-09-09 15:33 ` Paolo Bonzini
2011-09-09 9:00 ` [Qemu-devel] [PATCH 00/12] nbd improvements Kevin Wolf
2011-09-09 10:29 ` Paolo Bonzini
2011-09-09 10:42 ` Kevin Wolf
2011-09-09 10:50 ` Nicholas Thomas
2011-09-09 11:00 ` Paolo Bonzini
2011-09-09 11:04 ` Kevin Wolf
2011-09-09 14:51 ` Nicholas Thomas
2011-09-14 9:50 ` Kevin Wolf
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