From: Christoph Hellwig <hch@lst.de>
To: Avi Kivity <avi@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Stefan Hajnoczi <stefanha@gmail.com>,
qemu-devel@nongnu.org, Christoph Hellwig <hch@lst.de>,
Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Subject: Re: [Qemu-devel] [RFC] qed: Add QEMU Enhanced Disk format
Date: Fri, 10 Sep 2010 16:12:42 +0200 [thread overview]
Message-ID: <20100910141242.GA30542@lst.de> (raw)
In-Reply-To: <4C8A3B1C.4040807@redhat.com>
On Fri, Sep 10, 2010 at 05:05:16PM +0300, Avi Kivity wrote:
> >Note that ATA allows simply ignoring TRIM requests that we can't handle,
> >and if we don't set the bit that guarantees TRIMed regions to be zeroed
> >we don't even have to zero out the regions.
>
> It would be nice to support it. TRIM is important to recover space,
> otherwise images grow and grow and there's no point in using a sparse
> format in the first place.
Sure. But supporting to tiny TRIM requests doesn't make sense. That
is the same behaviour we see from real life SSDs, btw. If the request
is smaller than their erase block size or whatever internal structure
they use to track allocations it will not actually free space. On some
of the lesser quality consumer SSDs the sectors won't even be zeroed
even if they claim so in the ATA IDENTIFY response.
next prev parent reply other threads:[~2010-09-10 14:12 UTC|newest]
Thread overview: 132+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 10:04 [Qemu-devel] [RFC] qed: Add QEMU Enhanced Disk format Stefan Hajnoczi
2010-09-06 10:25 ` Alexander Graf
2010-09-06 10:31 ` Stefan Hajnoczi
2010-09-06 14:21 ` Luca Tettamanti
2010-09-06 14:24 ` Alexander Graf
2010-09-06 16:27 ` Anthony Liguori
2010-09-06 10:27 ` [Qemu-devel] " Kevin Wolf
2010-09-06 12:40 ` Stefan Hajnoczi
2010-09-06 12:57 ` Anthony Liguori
2010-09-06 13:02 ` Stefan Hajnoczi
2010-09-06 14:10 ` Kevin Wolf
2010-09-06 16:45 ` Anthony Liguori
2010-09-06 12:45 ` Anthony Liguori
2010-09-10 23:49 ` H. Peter Anvin
2010-09-06 11:18 ` [Qemu-devel] " Daniel P. Berrange
2010-09-06 12:52 ` Anthony Liguori
2010-09-06 13:35 ` Daniel P. Berrange
2010-09-06 16:38 ` Anthony Liguori
2010-09-06 13:06 ` Anthony Liguori
2010-09-07 14:51 ` Avi Kivity
2010-09-07 15:40 ` Anthony Liguori
2010-09-07 16:09 ` Avi Kivity
2010-09-07 16:25 ` Anthony Liguori
2010-09-07 22:27 ` Anthony Liguori
2010-09-08 8:23 ` Avi Kivity
2010-09-08 8:41 ` Alexander Graf
2010-09-08 8:53 ` Avi Kivity
2010-09-08 11:15 ` Stefan Hajnoczi
2010-09-08 15:38 ` Christoph Hellwig
2010-09-08 16:30 ` Anthony Liguori
2010-09-08 20:23 ` Christoph Hellwig
2010-09-08 20:28 ` Anthony Liguori
2010-09-09 2:35 ` Christoph Hellwig
2010-09-09 6:24 ` Avi Kivity
2010-09-09 21:01 ` Christoph Hellwig
2010-09-10 11:15 ` Avi Kivity
2010-09-09 6:53 ` Avi Kivity
2010-09-10 21:22 ` Jamie Lokier
2010-09-14 10:46 ` Stefan Hajnoczi
2010-09-14 11:08 ` Stefan Hajnoczi
2010-09-14 12:54 ` Anthony Liguori
2010-09-08 12:55 ` Anthony Liguori
2010-09-09 6:30 ` Avi Kivity
2010-09-08 12:48 ` Anthony Liguori
2010-09-08 13:20 ` Kevin Wolf
2010-09-08 13:26 ` Anthony Liguori
2010-09-08 13:46 ` Kevin Wolf
2010-09-09 6:45 ` Avi Kivity
2010-09-09 6:48 ` Avi Kivity
2010-09-09 12:49 ` Anthony Liguori
2010-09-09 16:48 ` [Qemu-devel] " Paolo Bonzini
2010-09-09 17:02 ` Anthony Liguori
2010-09-09 20:56 ` Christoph Hellwig
2010-09-10 10:53 ` Avi Kivity
2010-09-10 11:14 ` [Qemu-devel] " Avi Kivity
2010-09-10 11:25 ` Avi Kivity
2010-09-10 11:33 ` Stefan Hajnoczi
2010-09-10 11:43 ` Avi Kivity
2010-09-10 13:22 ` Anthony Liguori
2010-09-10 13:48 ` Christoph Hellwig
2010-09-10 15:02 ` Anthony Liguori
2010-09-10 15:18 ` Kevin Wolf
2010-09-10 15:53 ` Anthony Liguori
2010-09-10 16:05 ` Kevin Wolf
2010-09-10 17:10 ` Anthony Liguori
2010-09-10 17:44 ` Kevin Wolf
2010-09-10 17:46 ` Miguel Di Ciurcio Filho
2010-09-10 14:02 ` Avi Kivity
2010-09-10 13:47 ` Christoph Hellwig
2010-09-10 14:05 ` Avi Kivity
2010-09-10 14:12 ` Christoph Hellwig [this message]
2010-09-10 14:24 ` Avi Kivity
2010-09-10 13:16 ` Anthony Liguori
2010-09-10 14:06 ` Avi Kivity
2010-09-10 11:43 ` Stefan Hajnoczi
2010-09-10 12:06 ` Avi Kivity
2010-09-10 13:28 ` Anthony Liguori
2010-09-10 12:12 ` Kevin Wolf
2010-09-10 12:35 ` Stefan Hajnoczi
2010-09-10 12:47 ` Avi Kivity
2010-09-10 13:10 ` Stefan Hajnoczi
2010-09-10 13:19 ` Avi Kivity
2010-09-10 13:39 ` Anthony Liguori
2010-09-10 13:52 ` Christoph Hellwig
2010-09-10 13:56 ` Avi Kivity
2010-09-10 13:48 ` Kevin Wolf
2010-09-10 13:14 ` Anthony Liguori
2010-09-10 13:47 ` Avi Kivity
2010-09-10 14:56 ` Anthony Liguori
2010-09-10 15:49 ` Avi Kivity
2010-09-10 17:07 ` Anthony Liguori
2010-09-10 17:42 ` Kevin Wolf
2010-09-10 19:33 ` Anthony Liguori
2010-09-13 10:41 ` Kevin Wolf
2010-09-12 13:24 ` Avi Kivity
2010-09-12 15:13 ` Anthony Liguori
2010-09-12 15:56 ` Avi Kivity
2010-09-12 17:09 ` Anthony Liguori
2010-09-12 17:51 ` Avi Kivity
2010-09-12 20:18 ` Anthony Liguori
2010-09-13 9:24 ` Avi Kivity
2010-09-13 11:28 ` Kevin Wolf
2010-09-13 11:34 ` Avi Kivity
2010-09-13 11:48 ` Kevin Wolf
2010-09-13 13:19 ` Anthony Liguori
2010-09-13 13:12 ` Anthony Liguori
2010-09-13 11:03 ` Kevin Wolf
2010-09-13 13:07 ` Anthony Liguori
2010-09-13 13:24 ` Kevin Wolf
2010-09-07 16:12 ` Anthony Liguori
2010-09-07 21:35 ` Christoph Hellwig
2010-09-07 22:29 ` Anthony Liguori
2010-09-07 22:40 ` Christoph Hellwig
2010-09-08 15:07 ` Stefan Hajnoczi
2010-09-09 6:59 ` Avi Kivity
2010-09-09 17:43 ` Anthony Liguori
2010-09-09 20:46 ` Christoph Hellwig
2010-09-10 11:22 ` Avi Kivity
2010-09-10 11:29 ` Stefan Hajnoczi
2010-09-10 11:37 ` Avi Kivity
2010-09-07 13:58 ` Avi Kivity
2010-09-07 19:25 ` Blue Swirl
2010-09-07 20:41 ` Anthony Liguori
2010-09-08 7:48 ` Kevin Wolf
2010-09-08 15:37 ` Stefan Hajnoczi
2010-09-08 18:24 ` Blue Swirl
2010-09-08 18:35 ` Anthony Liguori
2010-09-08 18:56 ` Blue Swirl
2010-09-08 19:19 ` Anthony Liguori
2010-09-15 21:01 ` [Qemu-devel] " Michael S. Tsirkin
2010-09-15 21:12 ` Anthony Liguori
-- strict thread matches above, loose matches on Subject: below --
2010-09-17 3:51 [Qemu-devel] " Khoa Huynh
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