Re: [PATCH] MM: Support more pagesizes for MAP_HUGETLB/SHM_HUGETLB v6

From: Andi Kleen
Date: Mon Oct 22 2012 - 09:35:37 EST


On Mon, Oct 22, 2012 at 03:27:33PM +0200, Andi Kleen wrote:
> > Maybe I am missing something obvious, but does this not conflict with
> > include/uapi/asm-generic/mman-common.h:
> >
> > #ifdef CONFIG_MMAP_ALLOW_UNINITIALIZED
> > # define MAP_UNINITIALIZED 0x4000000
> > ...
> >
> > 0x4000000 == (1 << 26
> >
>
> You're right. Someone added that since I wrote the patch originally.
> I owned them when originally submitted @) Thanks for catching.
>
> Have to move my bits two up, which will still work, but limit the

Two up won't work, need one up.

32..28 = 16 is too small for 2^30 = 1GB pages
32..27 = 32 max 4GB pages

So this will use up all remaining flag bits now.

-Andi
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