mm: add p[te|md] protnone helpers for use by NUMA balancing
This is a preparatory patch that introduces protnone helpers for automatic
NUMA balancing.
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Acked-by: Aneesh Kumar K.V <[email protected]>
Tested-by: Sasha Levin <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Kirill Shutemov <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 129de92..067922c06c 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -673,6 +673,26 @@
#endif
}
+#ifndef CONFIG_NUMA_BALANCING
+/*
+ * Technically a PTE can be PROTNONE even when not doing NUMA balancing but
+ * the only case the kernel cares is for NUMA balancing and is only ever set
+ * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked
+ * _PAGE_PROTNONE so by by default, implement the helper as "always no". It
+ * is the responsibility of the caller to distinguish between PROT_NONE
+ * protections and NUMA hinting fault protections.
+ */
+static inline int pte_protnone(pte_t pte)
+{
+ return 0;
+}
+
+static inline int pmd_protnone(pmd_t pmd)
+{
+ return 0;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
#ifdef CONFIG_NUMA_BALANCING
/*
* _PAGE_NUMA distinguishes between an unmapped page table entry, an entry that
