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Date: Tue, 26 Jul 2011 15:04:28 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v2 04/23] memory: merge adjacent segments
 of a single memory region
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org

On 07/26/2011 02:51 PM, Paolo Bonzini wrote:
> On 07/26/2011 01:38 PM, Avi Kivity wrote:
>>>
>>> if (j != i) {
>>>
>>>> +        memmove(&view->ranges[i], &view->ranges[j],
>>>> +                (view->nr - j) * sizeof(view->ranges[j]));
>>>> +        view->nr -= j - i;
>>>> +    }
>>>
>>> }
>>
>> Seems to work both ways?
>
> Sure, but you're pointlessly memmove-ing memory over itself.  I'm not 
> sure how many segments a single memory region will usually have, but 
> it's better to be safe.

This will never be an issue in practice.  We expect to have few 
FlatRanges (O(100)), simplify() will be called very rarely (never during 
normal operations; a few dozen times during boot; a few during hotplug); 
everything is in L1 cache; and the cost will be dwarfed by any calls to 
kvm (if enabled).

-- 
error compiling committee.c: too many arguments to function