Re: [PATCH 1/2] mm: rename mm->nr_ptes to mm->nr_pgtables

From: Kirill A. Shutemov
Date: Tue Jan 13 2015 - 15:42:08 EST


On Tue, Jan 13, 2015 at 12:36:23PM -0800, Dave Hansen wrote:
> On 01/13/2015 11:14 AM, Kirill A. Shutemov wrote:
> > pgd_t * pgd;
> > atomic_t mm_users; /* How many users with user space? */
> > atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
> > - atomic_long_t nr_ptes; /* Page table pages */
> > + atomic_long_t nr_pgtables; /* Page table pages */
> > int map_count; /* number of VMAs */
>
> One more crazy idea...
>
> There are 2^9 possible pud pages, 2^18 pmd pages and 2^27 pte pages.
> That's only 54 bits (technically minus one bit each because the upper
> half of the address space is for the kernel).

Does this math make sense for all architecures? IA64? Power?

--
Kirill A. Shutemov
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