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From: Kevin Wolf <kwolf@redhat.com>
To: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Cc: qemu-devel@nongnu.org, stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH 0/5] qcow2: Discard freed clusters
Date: Tue, 18 Jun 2013 08:25:19 +0200	[thread overview]
Message-ID: <20130618062519.GA3640@dhcp-200-207.str.redhat.com> (raw)
In-Reply-To: <51BFCE0E.5050408@linux.vnet.ibm.com>

Am 18.06.2013 um 05:03 hat Wenchao Xia geschrieben:
> Hi, Kevin
>   In normal case, qcow2 is based on raw-posix file which don't support
> discard operation

It does, see raw_aio_discard().

> , so this serial doesn't change much in this case,
> still real space is not freed in snapshot delete, and it completes
> fast. Instead, tt affects the case that some protocol below support
> discard, so delete will be more clean but slower in that case. Is this
> true? Maybe add this in commit message?

Yes, it becomes a little bit slower, but not much in my tests.

Kevin

      reply	other threads:[~2013-06-18  6:25 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-06-13 11:47 [Qemu-devel] [PATCH 0/5] qcow2: Discard freed clusters Kevin Wolf
2013-06-13 11:47 ` [Qemu-devel] [PATCH 1/5] Revert "block: Disable driver-specific options for 1.5" Kevin Wolf
2013-06-13 11:47 ` [Qemu-devel] [PATCH 2/5] qcow2: Add refcount update reason to all callers Kevin Wolf
2013-06-13 11:47 ` [Qemu-devel] [PATCH 3/5] qcow2: Options to enable discard for freed clusters Kevin Wolf
2013-06-13 22:10   ` Paolo Bonzini
2013-06-14  8:31     ` Kevin Wolf
2013-06-14 14:16       ` Paolo Bonzini
2013-06-14 14:31         ` Kevin Wolf
2013-06-14 15:00           ` Paolo Bonzini
2013-06-17 15:41   ` Stefan Hajnoczi
2013-06-17 15:58     ` Kevin Wolf
2013-06-13 11:47 ` [Qemu-devel] [PATCH 4/5] qcow2: Batch discards Kevin Wolf
2013-06-17 15:45   ` Stefan Hajnoczi
2013-06-13 11:47 ` [Qemu-devel] [PATCH 5/5] block: Always enable discard on the protocol level Kevin Wolf
2013-06-13 22:06   ` Paolo Bonzini
2013-06-14  8:14     ` Kevin Wolf
2013-06-18  3:03 ` [Qemu-devel] [PATCH 0/5] qcow2: Discard freed clusters Wenchao Xia
2013-06-18  6:25   ` Kevin Wolf [this message]

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