From: Paolo Bonzini <pbonzini@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] qcow2: Simplify calculation for COW area at the end
Date: Tue, 12 Jun 2012 16:39:11 +0200 [thread overview]
Message-ID: <4FD7548F.80301@redhat.com> (raw)
In-Reply-To: <4FD75430.3090902@redhat.com>
Il 12/06/2012 16:37, Kevin Wolf ha scritto:
>> > align_offset(m->nb_available+1, s->cluster_sectors)
> Heh, yes, you're thinking about equivalence of the very formula (which
> is what I would do in unknown code as well), whereas I think about a COW
> operation that ranges from a given sector to the end of the same cluster
> (and not the next one).
>
> It's eventually the same, because this statement is only executed when
> it's not aligned (i.e. the COW range isn't empty):
>
> if (m->nb_available & (s->cluster_sectors - 1)) {
> ...
> }
Indeed, your version is ok.
Paolo
prev parent reply other threads:[~2012-06-12 14:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-12 13:47 [Qemu-devel] [PATCH] qcow2: Simplify calculation for COW area at the end Kevin Wolf
2012-06-12 14:00 ` Paolo Bonzini
2012-06-12 14:21 ` Kevin Wolf
2012-06-12 14:31 ` Paolo Bonzini
2012-06-12 14:37 ` Kevin Wolf
2012-06-12 14:39 ` Paolo Bonzini [this message]
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