Re: [RFC PATCH 0/6] Add support for shared PTEs across processes

[Matthew Wilcox]

On Tue, Jan 18, 2022 at 01:41:40PM -0800, Dave Hansen wrote:
> On 1/18/22 1:19 PM, Khalid Aziz wrote:
> > - Starting address must be aligned to pgdir size (512GB on x86_64)
> 
> How does this work on systems with 5-level paging where a top-level page
> table entry covers 256TB?  Is the alignment requirement 512GB or 256TB?
>  How does userspace figure out which alignment requirement it is subject to?

The original idea was any power of two, naturally aligned, >= PAGE_SIZE,
but I suspect Khalid has simplified it for this first implementation.