Re: [RFC] mm: Change the data type of huge page size from unsigned long to u64

[Rui Teng]

On 9/13/16 5:32 PM, Kirill A. Shutemov wrote:
> On Tue, Sep 13, 2016 at 05:26:05PM +0800, Rui Teng wrote:
> > The huge page size could be 16G(0x400000000) on ppc64 architecture, and it will
> > cause an overflow on unsigned long data type(0xFFFFFFFF).
>
> Huh? ppc64 is 64-bit system and sizeof(void *) is equal to
> sizeof(unsigned long) on Linux (LP64 model).
>
> So where your 0xFFFFFFFF comes from?
The size of unsigned long data type is 4 bytes, and the 0xFFFFFFFF here
is the maximum value. And 16G is bigger than it.