[tip: perf/core] mm: Introduce pXX_leaf_size()

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     93aec63b945579b679234ff5e5d7837baf2c7018
Gitweb:        https://git.kernel.org/tip/93aec63b945579b679234ff5e5d7837baf2c7018
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Fri, 13 Nov 2020 11:45:36 +01:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Thu, 03 Dec 2020 10:00:30 +01:00

mm: Introduce pXX_leaf_size()

A number of architectures have non-pagetable aligned huge/large pages.
For such architectures a leaf can actually be part of a larger entry.

Provide generic helpers to determine the size of a page-table leaf.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20201126121121.102580109@xxxxxxxxxxxxx
---
 include/linux/pgtable.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index c8602af..8fcdfa5 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1549,4 +1549,20 @@ typedef unsigned int pgtbl_mod_mask;
 #define pmd_leaf(x)	0
 #endif
 
+#ifndef pgd_leaf_size
+#define pgd_leaf_size(x) (1ULL << PGDIR_SHIFT)
+#endif
+#ifndef p4d_leaf_size
+#define p4d_leaf_size(x) P4D_SIZE
+#endif
+#ifndef pud_leaf_size
+#define pud_leaf_size(x) PUD_SIZE
+#endif
+#ifndef pmd_leaf_size
+#define pmd_leaf_size(x) PMD_SIZE
+#endif
+#ifndef pte_leaf_size
+#define pte_leaf_size(x) PAGE_SIZE
+#endif
+
 #endif /* _LINUX_PGTABLE_H */