Re: [PATCH 1/3] arm: Rename PMD_ORDER to PMD_TABLE_ORDER

From: Matthew Wilcox
Date: Thu Jul 15 2021 - 14:12:53 EST


On Thu, Jul 15, 2021 at 05:47:41PM +0100, Russell King (Oracle) wrote:
> On Thu, Jul 15, 2021 at 02:46:10PM +0100, Matthew Wilcox (Oracle) wrote:
> > This is the order of the page table allocation, not the order of a PMD.
> > -#define PMD_ORDER 3
> > +#define PMD_TABLE_ORDER 3
> > #else
> > #define PG_DIR_SIZE 0x4000
> > -#define PMD_ORDER 2
> > +#define PMD_TABLE_ORDER 2
>
> I think PMD_ENTRY_ORDER would make more sense here - this is the
> power-of-2 of an individual PMD entry, not of the entire table.

But ... we have two kinds of PMD entries. We have the direct entry that
points to a 1-16MB sized chunk of memory, and we have the table entry that
points to a 4k-32k chunk of memory that contains PTEs. So I don't think
calling it 'entry' order actually disambiguates anything. That's why
I went with 'table' -- I can't think of anything else to call it!
PMD_PTE_ARRAY_ORDER doesn't seem like an improvement to me ...