Hi,
> On Sun, May 21, 2023 at 09:02:36AM +0800, Wang Yugui wrote:
> > > +static inline unsigned fgp_order(size_t size)
> > > +{
> > > + unsigned int shift = ilog2(size);
> > > +
> > > + if (shift <= PAGE_SHIFT)
> > > + return 0;
> > > + return (shift - PAGE_SHIFT) << 26;
> >
> > int overflow will happen when size > 0.5M(2**19)?
>
> I don't see it?
>
> size == 1 << 20;
>
> shift = 20;
> return (20 - 12) << 26;
>
> Looks like about 1 << 29 to me.
sorry that I wrongly
1) wrongly conside PAGE_SHIFT as 13 from arch/alpha/include/asm/page.h
it should be 12 from arch/x86/include/asm/page_types.h.
2) wrongly conside
(20 - 12) << 26
as
1<< (20 - 12) << 26
Best Regards
Wang Yugui (wangyugui@xxxxxxxxxxxx)
2023/05/21
