From: Charlie Shepherd <charlie@ctshepherd.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kwolf@redhat.com, stefanha@gmail.com, gabriel@kerneis.info,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 1/2] Make cow_co_is_allocated and cow_update_bitmap more efficient
Date: Wed, 21 Aug 2013 10:11:47 +0100 [thread overview]
Message-ID: <52148453.8030109@ctshepherd.com> (raw)
In-Reply-To: <521476ED.5030308@redhat.com>
On 21/08/2013 09:14, Paolo Bonzini wrote:
> Il 21/08/2013 00:53, Charlie Shepherd ha scritto:
>> What if nb_sectors > 512 * 8?
> For cow_co_is_allocated, you have the luxury of returning information
> only for the fewer than nb_sectors. That is, you can set *num_same to a
> smaller value than nb_sectors, even if sector_num + *num_same has the
> same state as the [sector_num, sector_num + *num_same) range. It will
> cause extra calls to is_allocated in the callers, but that's it.
So we can report a conservative estimate of *num_same? It still seems
worthwhile to me to be as efficient as possible, I guess that means
processing a sector's worth of metadata at a time?
Charlie
next prev parent reply other threads:[~2013-08-21 9:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-20 18:34 [Qemu-devel] [PATCH 1/2] Make cow_co_is_allocated and cow_update_bitmap more efficient Charlie Shepherd
2013-08-20 18:37 ` Charlie Shepherd
2013-08-20 20:48 ` Paolo Bonzini
2013-08-20 22:53 ` Charlie Shepherd
2013-08-21 8:14 ` Paolo Bonzini
2013-08-21 9:11 ` Charlie Shepherd [this message]
2013-08-21 9:19 ` Paolo Bonzini
2013-08-21 10:31 ` Charlie Shepherd
2013-08-21 10:38 ` Paolo Bonzini
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