From patchwork series 484322

https://patchwork.ozlabs.org//project/linuxppc-dev/list/?series=484322

Author: Fox Snowpatch

arch/powerpc/Kconfig

@@ -137,7 +137,6 @@ config PPC
 	select ARCH_HAS_DMA_OPS			if PPC64
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_GCOV_PROFILE_ALL
-	select ARCH_HAS_GIGANTIC_PAGE		if ARCH_SUPPORTS_HUGETLBFS
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_KERNEL_FPU_SUPPORT	if PPC64 && PPC_FPU
 	select ARCH_HAS_MEMBARRIER_CALLBACKS

arch/powerpc/platforms/Kconfig.cputype

@@ -423,6 +423,7 @@ config PPC_64S_HASH_MMU
 config PPC_RADIX_MMU
 	bool "Radix MMU Support"
 	depends on PPC_BOOK3S_64
+	select ARCH_HAS_GIGANTIC_PAGE
 	default y
 	help
 	  Enable support for the Power ISA 3.0 Radix style MMU. Currently this

include/linux/mm.h

@@ -2074,7 +2074,7 @@ static inline unsigned long folio_nr_pages(const struct folio *folio)
 	return folio_large_nr_pages(folio);
 }
 
-#if !defined(CONFIG_HAVE_GIGANTIC_FOLIOS)
+#if !defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE)
 /*
  * We don't expect any folios that exceed buddy sizes (and consequently
  * memory sections).
@@ -2087,17 +2087,10 @@ static inline unsigned long folio_nr_pages(const struct folio *folio)
  * pages are guaranteed to be contiguous.
  */
 #define MAX_FOLIO_ORDER		PFN_SECTION_SHIFT
-#elif defined(CONFIG_HUGETLB_PAGE)
-/*
- * There is no real limit on the folio size. We limit them to the maximum we
- * currently expect (see CONFIG_HAVE_GIGANTIC_FOLIOS): with hugetlb, we expect
- * no folios larger than 16 GiB on 64bit and 1 GiB on 32bit.
- */
-#define MAX_FOLIO_ORDER		get_order(IS_ENABLED(CONFIG_64BIT) ? SZ_16G : SZ_1G)
 #else
 /*
- * Without hugetlb, gigantic folios that are bigger than a single PUD are
- * currently impossible.
+ * There is no real limit on the folio size. We limit them to the maximum we
+ * currently expect (e.g., hugetlb, dax).
  */
 #define MAX_FOLIO_ORDER		PUD_ORDER
 #endif

mm/Kconfig

@@ -908,13 +908,6 @@ config PAGE_MAPCOUNT
 config PGTABLE_HAS_HUGE_LEAVES
 	def_bool TRANSPARENT_HUGEPAGE || HUGETLB_PAGE
 
-#
-# We can end up creating gigantic folio.
-#
-config HAVE_GIGANTIC_FOLIOS
-	def_bool (HUGETLB_PAGE && ARCH_HAS_GIGANTIC_PAGE) || \
-		 (ZONE_DEVICE && HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
-
 # TODO: Allow to be enabled without THP
 config ARCH_SUPPORTS_HUGE_PFNMAP
 	def_bool n