2008-03-25 22:04:10

by J.C. Pizarro

Subject: What means Hugepage? 8KiB,16KiB,..,2MiB or 4MiB?

What means Hugepage?

Does it mean 8KiB? 16KiB? 32KiB? 64KiB? 2MiB? 4MiB?

The real page sizes of x86 and x86-64 are 4 KiB for this linux kernel.

But the page sizes can be soft 8 KiB or 16 KiB or 32 KiB or 64 KiB
if it is implemented in the memory manager of the kernel.

But too they exist real page sizes of 2 MiB and 4 MiB that they have
some reserved entries of TLB in the specs of Intel/AMD processors
for these gigant pages.

2008-03-25 23:00:13

by H. Peter Anvin

Subject: Re: What means Hugepage? 8KiB,16KiB,..,2MiB or 4MiB?

J.C. Pizarro wrote:
> What means Hugepage?
>
> Does it mean 8KiB? 16KiB? 32KiB? 64KiB? 2MiB? 4MiB?
>
> The real page sizes of x86 and x86-64 are 4 KiB for this linux kernel.
>
> But the page sizes can be soft 8 KiB or 16 KiB or 32 KiB or 64 KiB
> if it is implemented in the memory manager of the kernel.
>
> But too they exist real page sizes of 2 MiB and 4 MiB that they have
> some reserved entries of TLB in the specs of Intel/AMD processors
> for these gigant pages.

On x86, it means 2/4 MiB, or even 1 GiB in some very strange
circumstances. Other architectures might be different.

-hpa