Re: [PATCH 5/5] kvm: optimize GFN to memslot lookup with large slots amount

[Paolo Bonzini]

On 02/12/2014 18:33, Radim KrÄmÃÅ wrote:
>> > +	while (start < end) {
>> > +		slot = start + (end - start) / 2;
>> > +
>> > +		if (gfn >= memslots[slot].base_gfn)
> (Even thought division is costly, I think that checking here if 'slot'
>  is the one we want wouldn't help very much.)
> 

Division by an unsigned is just a right shift.  Division by signed
integer is a right shift + conditional move.  We can change / 2 to
explicit >> 1, or change start and end to unsigned, or both.

Paolo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/