Re: [Part1 PATCH v5 03/22] x86, ACPI, mm: Kill max_low_pfn_mapped

From: Tejun Heo
Date: Mon Jun 17 2013 - 19:08:22 EST


On Mon, Jun 17, 2013 at 2:13 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
>> No bigge, but why (1ULL << 32) - 1? Shouldn't it be just 1ULL << 32?
>> memblock deals with [@start, @end) areas, right?
>
> that is for 32bit, when phys_addr_t is 32bit, in that case
> (1ULL<<32) cast to 32bit would be 0.

Right, it'd work the same even after overflowing but yeah, it can be confusing.

Thanks.

--
tejun
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