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:

quoted

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 ...