[PATCH v5 00/14] mm: thp: always enable mTHP support

[PATCH v5 00/14] mm: thp: always enable mTHP support

[Luiz Capitulino]

Today, if an architecture implements has_transparent_hugepage() and the CPU
lacks support for PMD-sized pages, the THP code disables all THP, including
mTHP. In addition, the kernel lacks a well defined API to check for
PMD-sized page support. It currently relies on has_transparent_hugepage()
and thp_disabled_by_hw(), but they are not well defined and are tied to
THP support.

This series addresses both issues by introducing a new well defined API
to query PMD-sized page support: pgtable_has_pmd_leaves(). Using this
new helper, we ensure that mTHP remains enabled even when the
architecture or CPU doesn't support PMD-sized pages.

Thanks to David Hildenbrand for suggesting this improvement and for
providing guidance (all bugs and misconceptions are mine).

This applies to Linus tree eb3f4b7426cf ("Merge tag 'nfsd-7.1-2'
of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux")

NOTE: I used Claude Code Opus 4.6 to review the series before
posting. No issues found.

v5
--
- Moved init_arch_has_pmd_leaves() to mm_core_init() (David)
- Renamed init_arch_has_pmd_leaves() to pgtable_leaf_support_init() (Lance)
- Added new patch changing shmem_getattr() to set blksize according to
  highest supported THP order (Baolin)
- Added new patches to move has_transparent_hugepage() out of
  CONFIG_TRANSPARENT_HUGEPAGE guards (Sashiko)
- shmem_allowable_huge_orders(): rename variable and only disable
  PMD_ORDER (David)
- Added <linux/jmp_label.h> to include/linux/pgtable.h (Sashiko)
- Added new tags and removed Reviewed-by from changed patches

v4
--
- Used static key for pgtable_has_pmd_leaves() API (Lance)
- Moved shmem pgtable_has_pmd_leaves() check to
  shmem_allowable_huge_orders() (Baolin)
- Default pgtable_has_pmd_leaves() implementation to
  IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE) (Zi)
- Dropped patch “mm: thp: x86: cleanup PSE feature bit usage” (Dave)

v3
--
- Rebased on top of latest Linus tree
- Removed i915 patch as driver dropped has_transparent_hugepage() usage
- Moved init_arch_has_pmd_leaves() call in start_kernel() to avoid conflict
  with early_param handlers clearing CPU feature flags
- Fixed build error with CONFIG_MMU=n (kernel test robot)
- Fixed huge_anon_orders_inherit default setting when !pgtable_pmd_leaves() (Baolin)
- Small commit changelog improvements

v2
--
- Added support for always enabling mTHPs for shmem (Baolin)
- Improved commits changelog & added reviewed-by

v1
--
- Call init_arch_has_pmd_leaves() from start_kernel()
- Keep pgtable_has_pmd_leaves() calls tied to CONFIG_TRANSPARENT_HUGEPAGE (David)
- Clear PUD_ORDER when clearing PMD_ORDER (David)
- Small changelog improvements (David)
- Rebased on top of latest mm-new

Luiz Capitulino (14):
  docs: tmpfs: remove implementation detail reference
  mm: shmem: shmem_getattr(): set blksize to highest supported THP order
  mm: introduce pgtable_has_pmd_leaves()
  drivers: dax: use pgtable_has_pmd_leaves()
  drivers: nvdimm: use pgtable_has_pmd_leaves()
  mm: debug_vm_pgtable: use pgtable_has_pmd_leaves()
  mm: shmem: allow THP support determination at folio allocation time
  s390: move has_transparent_hugepage() out of THP guard
  powerpc: move has_transparent_hugepage() out of THP guard
  mips: move has_transparent_hugepage() out of THP guard
  x86: move has_transparent_hugepage() out of THP guard
  treewide: introduce arch_has_pmd_leaves()
  mm: replace thp_disabled_by_hw() with pgtable_has_pmd_leaves()
  mm: thp: always enable mTHP support

 Documentation/filesystems/tmpfs.rst           |  5 ++--
 arch/mips/include/asm/pgtable.h               |  6 ++--
 arch/mips/mm/tlb-r4k.c                        |  8 ++---
 arch/powerpc/include/asm/book3s/64/hash-4k.h  |  2 +-
 arch/powerpc/include/asm/book3s/64/hash-64k.h |  2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 18 ++++++------
 arch/powerpc/include/asm/book3s/64/radix.h    | 14 ++++-----
 arch/powerpc/mm/book3s64/hash_pgtable.c       |  8 ++---
 arch/s390/include/asm/pgtable.h               |  6 ++--
 arch/x86/include/asm/pgtable.h                | 12 ++++----
 drivers/dax/dax-private.h                     |  2 +-
 drivers/nvdimm/pfn_devs.c                     |  6 ++--
 include/linux/huge_mm.h                       |  7 -----
 include/linux/pgtable.h                       | 20 +++++++++++--
 mm/debug_vm_pgtable.c                         | 20 ++++++-------
 mm/huge_memory.c                              | 27 ++++++++++++-----
 mm/memory.c                                   | 11 ++++++-
 mm/mm_init.c                                  |  1 +
 mm/shmem.c                                    | 29 ++++++++++++-------
 19 files changed, 120 insertions(+), 84 deletions(-)

-- 
2.54.0

[PATCH v5 01/14] docs: tmpfs: remove implementation detail reference

[Luiz Capitulino]

The tmpfs.rst doc references the has_transparent_hugepage() helper, which
is an implementation detail in the kernel and not relevant for users
wishing to properly configure THP support for tmpfs. Remove it.

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 Documentation/filesystems/tmpfs.rst | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
index d677e0428c3f..46fc986c3388 100644
--- a/Documentation/filesystems/tmpfs.rst
+++ b/Documentation/filesystems/tmpfs.rst
@@ -109,9 +109,8 @@ noswap  Disables swap. Remounts must respect the original settings.
 ======  ===========================================================
 
 tmpfs also supports Transparent Huge Pages which requires a kernel
-configured with CONFIG_TRANSPARENT_HUGEPAGE and with huge supported for
-your system (has_transparent_hugepage(), which is architecture specific).
-The mount options for this are:
+configured with CONFIG_TRANSPARENT_HUGEPAGE and with huge pages
+supported for your system. The mount options for this are:
 
 ================ ==============================================================
 huge=never       Do not allocate huge pages.  This is the default.
-- 
2.54.0

[PATCH v5 02/14] mm: shmem: shmem_getattr(): set blksize to highest supported THP order

[Luiz Capitulino]

Today, shmem_getattr() sets stat->blksize to PMD size whenever
shmem_huge_global_enabled() returns non-zero. While this works fine
for the normal THP-enabled case as explained by Baolin in [1], this
has two problems:

 1. Theoretically, when shmem is configured for within_size, this
    could set blksize to PMD size even though the allocation may
    be a smaller mTHP order

 2. A future commit will allow shmem THP support to be enabled
    even when the CPU doesn't support PMD-sized pages. We should
    not allow blksize to be set to PMD size in this case

In order to fix #1 and prepare for #2, this commit sets blksize
to the size of the highest supported order returned by
shmem_huge_global_enabled().

  [1] https://lore.kernel.org/linux-mm/6591a74c-7ef9-4614-9ae9-cb2fbed86ebf@linux.alibaba.com/

Suggested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 mm/shmem.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 3b5dc21b323c..88bc0c292f1a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1286,6 +1286,7 @@ static int shmem_getattr(struct mnt_idmap *idmap,
 {
 	struct inode *inode = path->dentry->d_inode;
 	struct shmem_inode_info *info = SHMEM_I(inode);
+	unsigned int orders;
 
 	if (info->alloced - info->swapped != inode->i_mapping->nrpages)
 		shmem_recalc_inode(inode, 0, 0);
@@ -1301,8 +1302,9 @@ static int shmem_getattr(struct mnt_idmap *idmap,
 			STATX_ATTR_NODUMP);
 	generic_fillattr(idmap, request_mask, inode, stat);
 
-	if (shmem_huge_global_enabled(inode, 0, 0, false, NULL, 0))
-		stat->blksize = HPAGE_PMD_SIZE;
+	orders = shmem_huge_global_enabled(inode, 0, 0, false, NULL, 0);
+	if (orders)
+		stat->blksize = PAGE_SIZE << highest_order(orders);
 
 	if (request_mask & STATX_BTIME) {
 		stat->result_mask |= STATX_BTIME;
-- 
2.54.0

[PATCH v5 03/14] mm: introduce pgtable_has_pmd_leaves()

[Luiz Capitulino]

Currently, we have two helpers that check for PMD-sized pages but have
different names and slightly different semantics:

- has_transparent_hugepage(): the name suggests it checks if THP is
  enabled, but when CONFIG_TRANSPARENT_HUGEPAGE=y and the architecture
  implements this helper, it actually checks if the CPU supports
  PMD-sized pages

- thp_disabled_by_hw(): the name suggests it checks if THP is disabled
  by the hardware, but it just returns a cached value acquired with
  has_transparent_hugepage(). This helper is used in fast paths

This commit introduces a new helper called pgtable_has_pmd_leaves()
which is intended to replace both has_transparent_hugepage() and
thp_disabled_by_hw(). pgtable_has_pmd_leaves() has very clear semantics:
it returns true if the CPU supports PMD-sized pages and false otherwise.
It always returns a cached value, so it can be used in fast paths.

The new helper requires an initialization step which is performed by
pgtable_leaf_support_init(). We call pgtable_leaf_support_init() early
during boot from mm_core_init().

The next commits will convert users of both has_transparent_hugepage()
and thp_disabled_by_hw() to pgtable_has_pmd_leaves().

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 include/linux/pgtable.h | 16 ++++++++++++++++
 mm/memory.c             |  9 +++++++++
 mm/mm_init.c            |  1 +
 3 files changed, 26 insertions(+)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index cdd68ed3ae1a..d7899b95d3f1 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -14,6 +14,7 @@
 #include <linux/mm_types.h>
 #include <linux/bug.h>
 #include <linux/errno.h>
+#include <linux/jump_label.h>
 #include <asm-generic/pgtable_uffd.h>
 #include <linux/page_table_check.h>
 
@@ -2243,6 +2244,21 @@ static inline const char *pgtable_level_to_str(enum pgtable_level level)
 	}
 }
 
+#ifdef CONFIG_MMU
+DECLARE_STATIC_KEY_TRUE(__arch_has_pmd_leaves_key);
+static inline bool pgtable_has_pmd_leaves(void)
+{
+	return static_branch_likely(&__arch_has_pmd_leaves_key);
+}
+void __init pgtable_leaf_support_init(void);
+#else
+static inline bool pgtable_has_pmd_leaves(void)
+{
+	return false;
+}
+static inline void __init pgtable_leaf_support_init(void) { }
+#endif
+
 #endif /* !__ASSEMBLY__ */
 
 #if !defined(MAX_POSSIBLE_PHYSMEM_BITS) && !defined(CONFIG_64BIT)
diff --git a/mm/memory.c b/mm/memory.c
index 86a973119bd4..2f2bf7950daf 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -164,6 +164,15 @@ __setup("norandmaps", disable_randmaps);
 
 unsigned long highest_memmap_pfn __read_mostly;
 
+DEFINE_STATIC_KEY_TRUE(__arch_has_pmd_leaves_key);
+EXPORT_SYMBOL(__arch_has_pmd_leaves_key);
+
+void __init pgtable_leaf_support_init(void)
+{
+	if (!has_transparent_hugepage())
+		static_branch_disable(&__arch_has_pmd_leaves_key);
+}
+
 void mm_trace_rss_stat(struct mm_struct *mm, int member)
 {
 	trace_rss_stat(mm, member);
diff --git a/mm/mm_init.c b/mm/mm_init.c
index f9f8e1af921c..913d35fd67a0 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2697,6 +2697,7 @@ void __init mm_core_init(void)
 {
 	arch_mm_preinit();
 	init_zero_page_pfn();
+	pgtable_leaf_support_init();
 
 	/* Initializations relying on SMP setup */
 	BUILD_BUG_ON(MAX_ZONELISTS > 2);
-- 
2.54.0

[PATCH v5 04/14] drivers: dax: use pgtable_has_pmd_leaves()

[Luiz Capitulino]

dax_align_valid() uses has_transparent_hugepage() to check if PMD-sized
pages are supported, use pgtable_has_pmd_leaves() instead.

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 drivers/dax/dax-private.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index 81e4af49e39c..35744ff6592a 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -123,7 +123,7 @@ static inline bool dax_align_valid(unsigned long align)
 {
 	if (align == PUD_SIZE && IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD))
 		return true;
-	if (align == PMD_SIZE && has_transparent_hugepage())
+	if (align == PMD_SIZE && pgtable_has_pmd_leaves())
 		return true;
 	if (align == PAGE_SIZE)
 		return true;
-- 
2.54.0

[PATCH v5 05/14] drivers: nvdimm: use pgtable_has_pmd_leaves()

[Luiz Capitulino]

nd_pfn_supported_alignments() and nd_pfn_default_alignment() use
has_transparent_hugepage() to check if THP is supported with PMD-sized
pages. Use pgtable_has_pmd_leaves() instead. Also, check for
IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) to preserve the current
implementation semantics.

Acked-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 drivers/nvdimm/pfn_devs.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 8fa9c16aba7e..457eb54e7ab6 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -94,7 +94,8 @@ static unsigned long *nd_pfn_supported_alignments(unsigned long *alignments)
 
 	alignments[0] = PAGE_SIZE;
 
-	if (has_transparent_hugepage()) {
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+	    pgtable_has_pmd_leaves()) {
 		alignments[1] = HPAGE_PMD_SIZE;
 		if (has_transparent_pud_hugepage())
 			alignments[2] = HPAGE_PUD_SIZE;
@@ -109,7 +110,8 @@ static unsigned long *nd_pfn_supported_alignments(unsigned long *alignments)
 static unsigned long nd_pfn_default_alignment(void)
 {
 
-	if (has_transparent_hugepage())
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+	    pgtable_has_pmd_leaves())
 		return HPAGE_PMD_SIZE;
 	return PAGE_SIZE;
 }
-- 
2.54.0

[PATCH v5 06/14] mm: debug_vm_pgtable: use pgtable_has_pmd_leaves()

[Luiz Capitulino]

debug_vm_pgtable calls has_transparent_hugepage() in multiple places to
check if PMD-sized pages are supported, use pgtable_has_pmd_leaves()
instead.

Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 mm/debug_vm_pgtable.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 23dc3ee09561..bd53417dde2f 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -177,7 +177,7 @@ static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
 	unsigned long val = idx, *ptr = &val;
 	pmd_t pmd;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	pr_debug("Validating PMD basic (%pGv)\n", ptr);
@@ -222,7 +222,7 @@ static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
 	pmd_t pmd;
 	unsigned long vaddr = args->vaddr;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	page = (args->pmd_pfn != ULONG_MAX) ? pfn_to_page(args->pmd_pfn) : NULL;
@@ -283,7 +283,7 @@ static void __init pmd_leaf_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	pr_debug("Validating PMD leaf\n");
@@ -688,7 +688,7 @@ static void __init pmd_protnone_tests(struct pgtable_debug_args *args)
 	if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 		return;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	pr_debug("Validating PMD protnone\n");
@@ -737,7 +737,7 @@ static void __init pmd_soft_dirty_tests(struct pgtable_debug_args *args)
 	if (!pgtable_supports_soft_dirty())
 		return;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	pr_debug("Validating PMD soft dirty\n");
@@ -754,7 +754,7 @@ static void __init pmd_leaf_soft_dirty_tests(struct pgtable_debug_args *args)
 	    !IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
 		return;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	pr_debug("Validating PMD swap soft dirty\n");
@@ -825,7 +825,7 @@ static void __init pmd_softleaf_tests(struct pgtable_debug_args *args)
 	swp_entry_t arch_entry;
 	pmd_t pmd1, pmd2;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	pr_debug("Validating PMD swap\n");
@@ -906,7 +906,7 @@ static void __init pmd_thp_tests(struct pgtable_debug_args *args)
 {
 	pmd_t pmd;
 
-	if (!has_transparent_hugepage())
+	if (!pgtable_has_pmd_leaves())
 		return;
 
 	pr_debug("Validating PMD based THP\n");
@@ -997,7 +997,7 @@ static void __init destroy_args(struct pgtable_debug_args *args)
 	}
 
 	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
-	    has_transparent_hugepage() &&
+	    pgtable_has_pmd_leaves() &&
 	    args->pmd_pfn != ULONG_MAX) {
 		debug_vm_pgtable_free_huge_page(args, args->pmd_pfn, HPAGE_PMD_ORDER);
 		args->pmd_pfn = ULONG_MAX;
@@ -1249,7 +1249,7 @@ static int __init init_args(struct pgtable_debug_args *args)
 	}
 
 	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
-	    has_transparent_hugepage()) {
+	    pgtable_has_pmd_leaves()) {
 		page = debug_vm_pgtable_alloc_huge_page(args, HPAGE_PMD_ORDER);
 		if (page) {
 			args->pmd_pfn = page_to_pfn(page);
-- 
2.54.0

[PATCH v5 07/14] mm: shmem: allow THP support determination at folio allocation time

[Luiz Capitulino]

In order to enable THP support in shmem today, besides the user
configuration required, the CPU must support PMD-sized pages. This
is the case because of the following has_transparent_hugepage()
usage:

- shmem_parse_one() and shmem_parse_huge(): Check if THP is built-in and
  if the CPU supports PMD-sized pages

- shmem_init(): Since the CONFIG_TRANSPARENT_HUGEPAGE guard is outside
  the code block calling has_transparent_hugepage(), the
  has_transparent_hugepage() call is exclusively checking if the CPU
  supports PMD-sized pages

While it's necessary to check if CONFIG_TRANSPARENT_HUGEPAGE is enabled
in all cases, shmem can determine THP size support at folio allocation
time. Therefore, drop the has_transparent_hugepage() usage listed above
while keeping the CONFIG_TRANSPARENT_HUGEPAGE checks.

Additionally, we need to check if PMD size order is supported in
shmem_getattr(). Use pgtable_has_pmd_leaves() for that.

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 mm/shmem.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 88bc0c292f1a..108dc969b92a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -689,7 +689,7 @@ static int shmem_parse_huge(const char *str)
 	else
 		return -EINVAL;
 
-	if (!has_transparent_hugepage() &&
+	if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
 	    huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY)
 		return -EINVAL;
 
@@ -1303,6 +1303,8 @@ static int shmem_getattr(struct mnt_idmap *idmap,
 	generic_fillattr(idmap, request_mask, inode, stat);
 
 	orders = shmem_huge_global_enabled(inode, 0, 0, false, NULL, 0);
+	if (!pgtable_has_pmd_leaves())
+		orders &= ~BIT(PMD_ORDER);
 	if (orders)
 		stat->blksize = PAGE_SIZE << highest_order(orders);
 
@@ -4658,8 +4660,7 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 	case Opt_huge:
 		ctx->huge = result.uint_32;
 		if (ctx->huge != SHMEM_HUGE_NEVER &&
-		    !(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
-		      has_transparent_hugepage()))
+		    !IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
 			goto unsupported_parameter;
 		ctx->seen |= SHMEM_SEEN_HUGE;
 		break;
@@ -5451,7 +5452,7 @@ void __init shmem_init(void)
 #endif
 
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)
+	if (shmem_huge > SHMEM_HUGE_DENY)
 		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;
 	else
 		shmem_huge = SHMEM_HUGE_NEVER; /* just in case it was patched */
-- 
2.54.0

[PATCH v5 08/14] s390: move has_transparent_hugepage() out of THP guard

[Luiz Capitulino]

has_transparent_hugepage() definition is guarded by
CONFIG_TRANSPARENT_HUGEPAGE, but there's a need to use it when
CONFIG_TRANSPARENT_HUGEPAGE=n. Move the definition out of the THP guard.

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 arch/s390/include/asm/pgtable.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 2c6cee8241e0..5ed14221cc0e 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1798,13 +1798,13 @@ static inline int pmd_trans_huge(pmd_t pmd)
 {
 	return pmd_leaf(pmd);
 }
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #define has_transparent_hugepage has_transparent_hugepage
 static inline int has_transparent_hugepage(void)
 {
 	return cpu_has_edat1() ? 1 : 0;
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 #ifdef CONFIG_PAGE_TABLE_CHECK
 static inline bool pte_user_accessible_page(struct mm_struct *mm, unsigned long addr, pte_t pte)
-- 
2.54.0

[PATCH v5 09/14] powerpc: move has_transparent_hugepage() out of THP guard

[Luiz Capitulino]

has_transparent_hugepage() definition is guarded by
CONFIG_TRANSPARENT_HUGEPAGE, but there's a need to use it when
CONFIG_TRANSPARENT_HUGEPAGE=n. Move the definition out of the THP guard.

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 arch/powerpc/include/asm/book3s/64/hash-4k.h  |  2 +-
 arch/powerpc/include/asm/book3s/64/hash-64k.h |  2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 18 +++++++++---------
 arch/powerpc/include/asm/book3s/64/radix.h    | 14 +++++++-------
 arch/powerpc/mm/book3s64/hash_pgtable.c       |  4 ++--
 5 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
index 8e5bd9902bed..79511e6abfca 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
@@ -165,9 +165,9 @@ extern void hash__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 extern pgtable_t hash__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 				       unsigned long addr, pmd_t *pmdp);
-extern int hash__has_transparent_hugepage(void);
 #endif
 
+extern int hash__has_transparent_hugepage(void);
 #endif /* !__ASSEMBLER__ */
 
 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_4K_H */
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index 7deb3a66890b..a4a44a112ff9 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -278,9 +278,9 @@ extern void hash__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 extern pgtable_t hash__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
 extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 				       unsigned long addr, pmd_t *pmdp);
-extern int hash__has_transparent_hugepage(void);
 #endif /*  CONFIG_TRANSPARENT_HUGEPAGE */
 
+extern int hash__has_transparent_hugepage(void);
 #endif	/* __ASSEMBLER__ */
 
 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_64K_H */
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index e67e64ac6e8c..49c8beef96bb 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1121,15 +1121,6 @@ static inline void update_mmu_cache_pud(struct vm_area_struct *vma,
 {
 }
 
-extern int hash__has_transparent_hugepage(void);
-static inline int has_transparent_hugepage(void)
-{
-	if (radix_enabled())
-		return radix__has_transparent_hugepage();
-	return hash__has_transparent_hugepage();
-}
-#define has_transparent_hugepage has_transparent_hugepage
-
 static inline int has_transparent_pud_hugepage(void)
 {
 	if (radix_enabled())
@@ -1441,6 +1432,15 @@ static inline bool arch_needs_pgtable_deposit(void)
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+extern int hash__has_transparent_hugepage(void);
+static inline int has_transparent_hugepage(void)
+{
+	if (radix_enabled())
+		return radix__has_transparent_hugepage();
+	return hash__has_transparent_hugepage();
+}
+#define has_transparent_hugepage has_transparent_hugepage
+
 #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 pte_t ptep_modify_prot_start(struct vm_area_struct *, unsigned long, pte_t *);
 void ptep_modify_prot_commit(struct vm_area_struct *, unsigned long,
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index da954e779744..50545cf519bd 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -298,22 +298,22 @@ extern pmd_t radix__pmdp_huge_get_and_clear(struct mm_struct *mm,
 pud_t radix__pudp_huge_get_and_clear(struct mm_struct *mm,
 				     unsigned long addr, pud_t *pudp);
 
-static inline int radix__has_transparent_hugepage(void)
+static inline int radix__has_transparent_pud_hugepage(void)
 {
-	/* For radix 2M at PMD level means thp */
-	if (mmu_psize_defs[MMU_PAGE_2M].shift == PMD_SHIFT)
+	/* For radix 1G at PUD level means pud hugepage support */
+	if (mmu_psize_defs[MMU_PAGE_1G].shift == PUD_SHIFT)
 		return 1;
 	return 0;
 }
+#endif
 
-static inline int radix__has_transparent_pud_hugepage(void)
+static inline int radix__has_transparent_hugepage(void)
 {
-	/* For radix 1G at PUD level means pud hugepage support */
-	if (mmu_psize_defs[MMU_PAGE_1G].shift == PUD_SHIFT)
+	/* For radix 2M at PMD level means thp */
+	if (mmu_psize_defs[MMU_PAGE_2M].shift == PMD_SHIFT)
 		return 1;
 	return 0;
 }
-#endif
 
 struct vmem_altmap;
 struct dev_pagemap;
diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c
index d9b5b751d7b7..50316f3fc5d3 100644
--- a/arch/powerpc/mm/book3s64/hash_pgtable.c
+++ b/arch/powerpc/mm/book3s64/hash_pgtable.c
@@ -391,6 +391,8 @@ pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 	return old_pmd;
 }
 
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
 int hash__has_transparent_hugepage(void)
 {
 
@@ -422,8 +424,6 @@ int hash__has_transparent_hugepage(void)
 }
 EXPORT_SYMBOL_GPL(hash__has_transparent_hugepage);
 
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-
 #ifdef CONFIG_STRICT_KERNEL_RWX
 
 struct change_memory_parms {
-- 
2.54.0

[PATCH v5 10/14] mips: move has_transparent_hugepage() out of THP guard

[Luiz Capitulino]

has_transparent_hugepage() definition is guarded by
CONFIG_TRANSPARENT_HUGEPAGE, but there's a need to use it when
CONFIG_TRANSPARENT_HUGEPAGE=n. Move the definition out of the THP guard.

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 arch/mips/include/asm/pgtable.h | 6 +++---
 arch/mips/mm/tlb-r4k.c          | 4 ----
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index fa7b935f947c..b038da872ec6 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -615,9 +615,6 @@ unsigned long io_remap_pfn_range_pfn(unsigned long pfn, unsigned long size);
 /* We don't have hardware dirty/accessed bits, generic_pmdp_establish is fine.*/
 #define pmdp_establish generic_pmdp_establish
 
-#define has_transparent_hugepage has_transparent_hugepage
-extern int has_transparent_hugepage(void);
-
 static inline int pmd_trans_huge(pmd_t pmd)
 {
 	return !!(pmd_val(pmd) & _PAGE_HUGE);
@@ -743,6 +740,9 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+#define has_transparent_hugepage has_transparent_hugepage
+extern int has_transparent_hugepage(void);
+
 #ifdef _PAGE_HUGE
 #define pmd_leaf(pmd)	((pmd_val(pmd) & _PAGE_HUGE) != 0)
 #define pud_leaf(pud)	((pud_val(pud) & _PAGE_HUGE) != 0)
diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
index 24fe85fa169d..f4e369342a56 100644
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -432,8 +432,6 @@ void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 #endif
 }
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-
 int has_transparent_hugepage(void)
 {
 	static unsigned int mask = -1;
@@ -452,8 +450,6 @@ int has_transparent_hugepage(void)
 }
 EXPORT_SYMBOL(has_transparent_hugepage);
 
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE  */
-
 /*
  * Used for loading TLB entries before trap_init() has started, when we
  * don't actually want to add a wired entry which remains throughout the
-- 
2.54.0

[PATCH v5 11/14] x86: move has_transparent_hugepage() out of THP guard

[Luiz Capitulino]

has_transparent_hugepage() definition is guarded by
CONFIG_TRANSPARENT_HUGEPAGE, but there's a need to use it when
CONFIG_TRANSPARENT_HUGEPAGE=n. Move the definition out of the THP guard.

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 arch/x86/include/asm/pgtable.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 2187e9cfcefa..30fd1fa034e4 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -306,12 +306,6 @@ static inline int pud_trans_huge(pud_t pud)
 }
 #endif
 
-#define has_transparent_hugepage has_transparent_hugepage
-static inline int has_transparent_hugepage(void)
-{
-	return boot_cpu_has(X86_FEATURE_PSE);
-}
-
 #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
 static inline bool pmd_special(pmd_t pmd)
 {
@@ -337,6 +331,12 @@ static inline pud_t pud_mkspecial(pud_t pud)
 #endif	/* CONFIG_ARCH_SUPPORTS_PUD_PFNMAP */
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+#define has_transparent_hugepage has_transparent_hugepage
+static inline int has_transparent_hugepage(void)
+{
+	return boot_cpu_has(X86_FEATURE_PSE);
+}
+
 static inline pte_t pte_set_flags(pte_t pte, pteval_t set)
 {
 	pteval_t v = native_pte_val(pte);
-- 
2.54.0

[PATCH v5 12/14] treewide: introduce arch_has_pmd_leaves()

[Luiz Capitulino]

Now that all the has_transparent_hugepage() callers have been converted
to pgtable_has_pmd_leaves(), this commit does two things:

1. Rename has_transparent_hugepage() arch implementations to
   arch_has_pmd_leaves(), since that's what the helper checks for

2. Introduce the default implementation of arch_has_pmd_leaves() as
   IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE). This means that if
   the arch doesn't implement arch_has_pmd_leaves() we default to checking
   CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE as a way to determine if
   PMD-sized pages are supported

Note that arch_has_pmd_leaves() is supposed to be called only by
init_arch_has_pmd_leaves(). The remaining exception is hugepage_init()
which will be converted in a future commit.

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 arch/mips/include/asm/pgtable.h               |  4 ++--
 arch/mips/mm/tlb-r4k.c                        |  4 ++--
 arch/powerpc/include/asm/book3s/64/hash-4k.h  |  2 +-
 arch/powerpc/include/asm/book3s/64/hash-64k.h |  2 +-
 arch/powerpc/include/asm/book3s/64/pgtable.h  | 10 +++++-----
 arch/powerpc/include/asm/book3s/64/radix.h    |  2 +-
 arch/powerpc/mm/book3s64/hash_pgtable.c       |  4 ++--
 arch/s390/include/asm/pgtable.h               |  4 ++--
 arch/x86/include/asm/pgtable.h                |  4 ++--
 include/linux/pgtable.h                       |  4 ++--
 mm/huge_memory.c                              |  2 +-
 mm/memory.c                                   |  2 +-
 12 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index b038da872ec6..2a0a7ddf8bee 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -740,8 +740,8 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-#define has_transparent_hugepage has_transparent_hugepage
-extern int has_transparent_hugepage(void);
+#define arch_has_pmd_leaves arch_has_pmd_leaves
+extern int arch_has_pmd_leaves(void);
 
 #ifdef _PAGE_HUGE
 #define pmd_leaf(pmd)	((pmd_val(pmd) & _PAGE_HUGE) != 0)
diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c
index f4e369342a56..9339ebb0815f 100644
--- a/arch/mips/mm/tlb-r4k.c
+++ b/arch/mips/mm/tlb-r4k.c
@@ -432,7 +432,7 @@ void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1,
 #endif
 }
 
-int has_transparent_hugepage(void)
+int arch_has_pmd_leaves(void)
 {
 	static unsigned int mask = -1;
 
@@ -448,7 +448,7 @@ int has_transparent_hugepage(void)
 	}
 	return mask == PM_HUGE_MASK;
 }
-EXPORT_SYMBOL(has_transparent_hugepage);
+EXPORT_SYMBOL(arch_has_pmd_leaves);
 
 /*
  * Used for loading TLB entries before trap_init() has started, when we
diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
index 79511e6abfca..d532e3f0dfc3 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
@@ -167,7 +167,7 @@ extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 				       unsigned long addr, pmd_t *pmdp);
 #endif
 
-extern int hash__has_transparent_hugepage(void);
+extern int hash__arch_has_pmd_leaves(void);
 #endif /* !__ASSEMBLER__ */
 
 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_4K_H */
diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
index a4a44a112ff9..d523c80f44f7 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
@@ -280,7 +280,7 @@ extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 				       unsigned long addr, pmd_t *pmdp);
 #endif /*  CONFIG_TRANSPARENT_HUGEPAGE */
 
-extern int hash__has_transparent_hugepage(void);
+extern int hash__arch_has_pmd_leaves(void);
 #endif	/* __ASSEMBLER__ */
 
 #endif /* _ASM_POWERPC_BOOK3S_64_HASH_64K_H */
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 49c8beef96bb..a5005d1d2a7d 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1432,14 +1432,14 @@ static inline bool arch_needs_pgtable_deposit(void)
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-extern int hash__has_transparent_hugepage(void);
-static inline int has_transparent_hugepage(void)
+extern int hash__arch_has_pmd_leaves(void);
+static inline int arch_has_pmd_leaves(void)
 {
 	if (radix_enabled())
-		return radix__has_transparent_hugepage();
-	return hash__has_transparent_hugepage();
+		return radix__arch_has_pmd_leaves();
+	return hash__arch_has_pmd_leaves();
 }
-#define has_transparent_hugepage has_transparent_hugepage
+#define arch_has_pmd_leaves arch_has_pmd_leaves
 
 #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
 pte_t ptep_modify_prot_start(struct vm_area_struct *, unsigned long, pte_t *);
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 50545cf519bd..e8b74528953f 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -307,7 +307,7 @@ static inline int radix__has_transparent_pud_hugepage(void)
 }
 #endif
 
-static inline int radix__has_transparent_hugepage(void)
+static inline int radix__arch_has_pmd_leaves(void)
 {
 	/* For radix 2M at PMD level means thp */
 	if (mmu_psize_defs[MMU_PAGE_2M].shift == PMD_SHIFT)
diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c
index 50316f3fc5d3..a67bc1723404 100644
--- a/arch/powerpc/mm/book3s64/hash_pgtable.c
+++ b/arch/powerpc/mm/book3s64/hash_pgtable.c
@@ -393,7 +393,7 @@ pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
 
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-int hash__has_transparent_hugepage(void)
+int hash__arch_has_pmd_leaves(void)
 {
 
 	if (!mmu_has_feature(MMU_FTR_16M_PAGE))
@@ -422,7 +422,7 @@ int hash__has_transparent_hugepage(void)
 
 	return 1;
 }
-EXPORT_SYMBOL_GPL(hash__has_transparent_hugepage);
+EXPORT_SYMBOL_GPL(hash__arch_has_pmd_leaves);
 
 #ifdef CONFIG_STRICT_KERNEL_RWX
 
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 5ed14221cc0e..f949d6988a41 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1800,8 +1800,8 @@ static inline int pmd_trans_huge(pmd_t pmd)
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-#define has_transparent_hugepage has_transparent_hugepage
-static inline int has_transparent_hugepage(void)
+#define arch_has_pmd_leaves arch_has_pmd_leaves
+static inline int arch_has_pmd_leaves(void)
 {
 	return cpu_has_edat1() ? 1 : 0;
 }
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 30fd1fa034e4..2badbe882637 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -331,8 +331,8 @@ static inline pud_t pud_mkspecial(pud_t pud)
 #endif	/* CONFIG_ARCH_SUPPORTS_PUD_PFNMAP */
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
-#define has_transparent_hugepage has_transparent_hugepage
-static inline int has_transparent_hugepage(void)
+#define arch_has_pmd_leaves arch_has_pmd_leaves
+static inline int arch_has_pmd_leaves(void)
 {
 	return boot_cpu_has(X86_FEATURE_PSE);
 }
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index d7899b95d3f1..57148c50f6d9 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -2274,8 +2274,8 @@ static inline void __init pgtable_leaf_support_init(void) { }
 #endif
 #endif
 
-#ifndef has_transparent_hugepage
-#define has_transparent_hugepage() IS_BUILTIN(CONFIG_TRANSPARENT_HUGEPAGE)
+#ifndef arch_has_pmd_leaves
+#define arch_has_pmd_leaves() IS_BUILTIN(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE)
 #endif
 
 #ifndef has_transparent_pud_hugepage
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 970e077019b7..4da10e94bbb6 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -969,7 +969,7 @@ static int __init hugepage_init(void)
 	int err;
 	struct kobject *hugepage_kobj;
 
-	if (!has_transparent_hugepage()) {
+	if (!arch_has_pmd_leaves()) {
 		transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED;
 		return -EINVAL;
 	}
diff --git a/mm/memory.c b/mm/memory.c
index 2f2bf7950daf..953d8d1ea268 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -169,7 +169,7 @@ EXPORT_SYMBOL(__arch_has_pmd_leaves_key);
 
 void __init pgtable_leaf_support_init(void)
 {
-	if (!has_transparent_hugepage())
+	if (!arch_has_pmd_leaves())
 		static_branch_disable(&__arch_has_pmd_leaves_key);
 }
 
-- 
2.54.0

[PATCH v5 13/14] mm: replace thp_disabled_by_hw() with pgtable_has_pmd_leaves()

[Luiz Capitulino]

Despite its name, thp_disabled_by_hw() just checks whether the
architecture supports PMD-sized pages. It returns true when
TRANSPARENT_HUGEPAGE_UNSUPPORTED is set in transparent_hugepage_flags,
this only occurs if the architecture implements arch_has_pmd_leaves()
and that function returns false.

Since pgtable_has_pmd_leaves() provides the same semantics, use it
instead.

Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 include/linux/huge_mm.h | 7 -------
 mm/huge_memory.c        | 6 ++----
 mm/memory.c             | 2 +-
 mm/shmem.c              | 2 +-
 4 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 2949e5acff35..da048aa06761 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -47,7 +47,6 @@ vm_fault_t vmf_insert_folio_pud(struct vm_fault *vmf, struct folio *folio,
 				bool write);
 
 enum transparent_hugepage_flag {
-	TRANSPARENT_HUGEPAGE_UNSUPPORTED,
 	TRANSPARENT_HUGEPAGE_FLAG,
 	TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
 	TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
@@ -352,12 +351,6 @@ static inline bool vma_thp_disabled(struct vm_area_struct *vma,
 	return mm_flags_test(MMF_DISABLE_THP_EXCEPT_ADVISED, vma->vm_mm);
 }
 
-static inline bool thp_disabled_by_hw(void)
-{
-	/* If the hardware/firmware marked hugepage support disabled. */
-	return transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED);
-}
-
 unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
 		unsigned long len, unsigned long pgoff, unsigned long flags);
 unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long addr,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4da10e94bbb6..32254febe097 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -133,7 +133,7 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 	if (!vma->vm_mm)		/* vdso */
 		return 0;
 
-	if (thp_disabled_by_hw() || vma_thp_disabled(vma, vm_flags, forced_collapse))
+	if (!pgtable_has_pmd_leaves() || vma_thp_disabled(vma, vm_flags, forced_collapse))
 		return 0;
 
 	/* khugepaged doesn't collapse DAX vma, but page fault is fine. */
@@ -969,10 +969,8 @@ static int __init hugepage_init(void)
 	int err;
 	struct kobject *hugepage_kobj;
 
-	if (!arch_has_pmd_leaves()) {
-		transparent_hugepage_flags = 1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED;
+	if (!pgtable_has_pmd_leaves())
 		return -EINVAL;
-	}
 
 	/*
 	 * hugepages can't be allocated by the buddy allocator
diff --git a/mm/memory.c b/mm/memory.c
index 953d8d1ea268..707a9867c034 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5538,7 +5538,7 @@ vm_fault_t do_set_pmd(struct vm_fault *vmf, struct folio *folio, struct page *pa
 	 * PMD mappings if THPs are disabled. As we already have a THP,
 	 * behave as if we are forcing a collapse.
 	 */
-	if (thp_disabled_by_hw() || vma_thp_disabled(vma, vma->vm_flags,
+	if (!pgtable_has_pmd_leaves() || vma_thp_disabled(vma, vma->vm_flags,
 						     /* forced_collapse=*/ true))
 		return ret;
 
diff --git a/mm/shmem.c b/mm/shmem.c
index 108dc969b92a..079e299ea789 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1846,7 +1846,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
 	vm_flags_t vm_flags = vma ? vma->vm_flags : 0;
 	unsigned int global_orders;
 
-	if (thp_disabled_by_hw() || (vma && vma_thp_disabled(vma, vm_flags, shmem_huge_force)))
+	if (!pgtable_has_pmd_leaves() || (vma && vma_thp_disabled(vma, vm_flags, shmem_huge_force)))
 		return 0;
 
 	global_orders = shmem_huge_global_enabled(inode, index, write_end,
-- 
2.54.0

[PATCH v5 14/14] mm: thp: always enable mTHP support

[Luiz Capitulino]

If PMD-sized pages are not supported on an architecture (ie. the
arch implements arch_has_pmd_leaves() and it returns false) then the
current code disables all THP, including mTHP.

This commit fixes this by allowing mTHP to be always enabled for all
archs. When PMD-sized pages are not supported, its sysfs entry won't be
created and their mapping will be disallowed at page-fault time.

Similarly, this commit implements the following changes for shmem in
shmem_allowable_huge_orders():

 - Drop the pgtable_has_pmd_leaves() check so that mTHP sizes are
   considered
 - Filter out PMD and PUD orders from allowable orders when
   PMD-sized pages are not supported by the CPU

Signed-off-by: Luiz Capitulino <luizcap@redhat.com>
---
 mm/huge_memory.c | 25 ++++++++++++++++++++-----
 mm/shmem.c       | 14 +++++++++-----
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 32254febe097..059901a8c6cb 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -126,6 +126,15 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 	else
 		supported_orders = THP_ORDERS_ALL_FILE_DEFAULT;
 
+	if (!pgtable_has_pmd_leaves()) {
+		/*
+		 * If the CPU does not support PMD leaves, assume for
+		 * now that it does not support PUD leaves and disable
+		 * both folio orders.
+		 */
+		supported_orders &= ~(BIT(PMD_ORDER) | BIT(PUD_ORDER));
+	}
+
 	orders &= supported_orders;
 	if (!orders)
 		return 0;
@@ -133,7 +142,7 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 	if (!vma->vm_mm)		/* vdso */
 		return 0;
 
-	if (!pgtable_has_pmd_leaves() || vma_thp_disabled(vma, vm_flags, forced_collapse))
+	if (vma_thp_disabled(vma, vm_flags, forced_collapse))
 		return 0;
 
 	/* khugepaged doesn't collapse DAX vma, but page fault is fine. */
@@ -848,7 +857,7 @@ static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
 	 * disable all other sizes. powerpc's PMD_ORDER isn't a compile-time
 	 * constant so we have to do this here.
 	 */
-	if (!anon_orders_configured)
+	if (!anon_orders_configured && pgtable_has_pmd_leaves())
 		huge_anon_orders_inherit = BIT(PMD_ORDER);
 
 	*hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
@@ -870,6 +879,15 @@ static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj)
 	}
 
 	orders = THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DEFAULT;
+	if (!pgtable_has_pmd_leaves()) {
+		/*
+		 * If the CPU does not support PMD leaves, assume for
+		 * now that it does not support PUD leaves and disable
+		 * both folio orders.
+		 */
+		orders &= ~(BIT(PMD_ORDER) | BIT(PUD_ORDER));
+	}
+
 	order = highest_order(orders);
 	while (orders) {
 		thpsize = thpsize_create(order, *hugepage_kobj);
@@ -969,9 +987,6 @@ static int __init hugepage_init(void)
 	int err;
 	struct kobject *hugepage_kobj;
 
-	if (!pgtable_has_pmd_leaves())
-		return -EINVAL;
-
 	/*
 	 * hugepages can't be allocated by the buddy allocator
 	 */
diff --git a/mm/shmem.c b/mm/shmem.c
index 079e299ea789..c15dffd0eb41 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1844,16 +1844,19 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
 	unsigned long mask = READ_ONCE(huge_shmem_orders_always);
 	unsigned long within_size_orders = READ_ONCE(huge_shmem_orders_within_size);
 	vm_flags_t vm_flags = vma ? vma->vm_flags : 0;
-	unsigned int global_orders;
+	unsigned int global_orders, disabled_orders = 0;
 
-	if (!pgtable_has_pmd_leaves() || (vma && vma_thp_disabled(vma, vm_flags, shmem_huge_force)))
+	if (vma && vma_thp_disabled(vma, vm_flags, shmem_huge_force))
 		return 0;
 
+	if (!pgtable_has_pmd_leaves())
+		disabled_orders = BIT(PMD_ORDER);
+
 	global_orders = shmem_huge_global_enabled(inode, index, write_end,
 						  shmem_huge_force, vma, vm_flags);
 	/* Tmpfs huge pages allocation */
 	if (!vma || !vma_is_anon_shmem(vma))
-		return global_orders;
+		return global_orders & ~disabled_orders;
 
 	/*
 	 * Following the 'deny' semantics of the top level, force the huge
@@ -1867,7 +1870,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
 	 * means non-PMD sized THP can not override 'huge' mount option now.
 	 */
 	if (shmem_huge == SHMEM_HUGE_FORCE)
-		return READ_ONCE(huge_shmem_orders_inherit);
+		return READ_ONCE(huge_shmem_orders_inherit) & ~disabled_orders;
 
 	/* Allow mTHP that will be fully within i_size. */
 	mask |= shmem_get_orders_within_size(inode, within_size_orders, index, 0);
@@ -1878,6 +1881,7 @@ unsigned long shmem_allowable_huge_orders(struct inode *inode,
 	if (global_orders > 0)
 		mask |= READ_ONCE(huge_shmem_orders_inherit);
 
+	mask &= ~disabled_orders;
 	return THP_ORDERS_ALL_FILE_DEFAULT & mask;
 }
 
@@ -5461,7 +5465,7 @@ void __init shmem_init(void)
 	 * Default to setting PMD-sized THP to inherit the global setting and
 	 * disable all other multi-size THPs.
 	 */
-	if (!shmem_orders_configured)
+	if (!shmem_orders_configured && pgtable_has_pmd_leaves())
 		huge_shmem_orders_inherit = BIT(HPAGE_PMD_ORDER);
 #endif
 	return;
-- 
2.54.0