thp: special pmd_trans_* functions These returns 0 at compile time when the config option is disabled, to allow gcc to eliminate the transparent hugepage function calls at compile time without additional #ifdefs (only the export of those functions have to be visible to gcc but they won't be required at link time and huge_memory.o can be not built at all). _PAGE_BIT_UNUSED1 is never used for pmd, only on pte. Signed-off-by: Andrea Arcangeli <[email protected]> Acked-by: Rik van Riel <[email protected]> Acked-by: Mel Gorman <[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 6f3c6ae..0ab2cd2 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h

@@ -348,6 +348,17 @@
 				unsigned long size);
 #endif
 
+#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+static inline int pmd_trans_huge(pmd_t pmd)
+{
+	return 0;
+}
+static inline int pmd_trans_splitting(pmd_t pmd)
+{
+	return 0;
+}
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #endif /* _ASM_GENERIC_PGTABLE_H */