linux-kernel - [PATCH] Revert "mm: fix MAX_FOLIO_ORDER on powerpc configs with hugetlb"

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Message-ID: <20251204023358.54107-1-skhan@linuxfoundation.org>
Date: Wed,  3 Dec 2025 19:33:56 -0700
From: Shuah Khan <skhan@...uxfoundation.org>
To: akpm@...ux-foundation.org,
	david@...nel.org
Cc: Shuah Khan <skhan@...uxfoundation.org>,
	maddy@...ux.ibm.com,
	mpe@...erman.id.au,
	npiggin@...il.com,
	christophe.leroy@...roup.eu,
	lorenzo.stoakes@...cle.com,
	Liam.Howlett@...cle.com,
	vbabka@...e.cz,
	rppt@...nel.org,
	surenb@...gle.com,
	mhocko@...e.com,
	masahiroy@...nel.org,
	linuxppc-dev@...ts.ozlabs.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH] Revert "mm: fix MAX_FOLIO_ORDER on powerpc configs with hugetlb"

This reverts commit 39231e8d6ba7f794b566fd91ebd88c0834a23b98.

Enabling HAVE_GIGANTIC_FOLIOS broke kernel build and git clone on two
systems. git fetch-pack fails when cloning large repos and make hangs
or errors out of Makefile.build with Error: 139. These failures are
random with git clone failing after fetching 1% of the objects, and
make hangs while compiling random files.

The blow is is one of the git clone failures:

git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux_6.19
Cloning into 'linux_6.19'...
remote: Enumerating objects: 11173575, done.
remote: Counting objects: 100% (785/785), done.
remote: Compressing objects: 100% (373/373), done.
remote: Total 11173575 (delta 534), reused 505 (delta 411), pack-reused 11172790 (from 1)
Receiving objects: 100% (11173575/11173575), 3.00 GiB | 7.08 MiB/s, done.
Resolving deltas: 100% (9195212/9195212), done.
fatal: did not receive expected object 0002003e951b5057c16de5a39140abcbf6e44e50
fatal: fetch-pack: invalid index-pack output

Signed-off-by: Shuah Khan <skhan@...uxfoundation.org>
---
 arch/powerpc/Kconfig                   |  1 -
 arch/powerpc/platforms/Kconfig.cputype |  1 +
 include/linux/mm.h                     | 13 +++----------
 mm/Kconfig                             |  7 -------
 4 files changed, 4 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9537a61ebae0..e24f4d88885a 100644
--- a/arch/powerpc/Kconfig
+++ b/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
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index 4c321a8ea896..7b527d18aa5e 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/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
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7c79b3369b82..d16b33bacc32 100644
--- a/include/linux/mm.h
+++ b/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
diff --git a/mm/Kconfig b/mm/Kconfig
index ca3f146bc705..0e26f4fc8717 100644
--- a/mm/Kconfig
+++ b/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
-- 
2.51.0