* [PATCH v6 01/14] docs: tmpfs: remove implementation detail reference
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 02/14] mm: shmem: shmem_getattr(): set blksize to highest supported THP order Luiz Capitulino
` (12 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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>
Reviewed-by: Dev Jain <dev.jain@arm.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.
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 02/14] mm: shmem: shmem_getattr(): set blksize to highest supported THP order
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 01/14] docs: tmpfs: remove implementation detail reference Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 03/14] mm: introduce pgtable_has_pmd_leaves() Luiz Capitulino
` (11 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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>
Acked-by: Zi Yan <ziy@nvidia.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 5071177059a9..19534e21b61f 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1287,6 +1287,7 @@ 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;
/* Fast-path hint; recalc under info->lock corrects any stale read. */
if (data_race(info->alloced - info->swapped != inode->i_mapping->nrpages))
@@ -1303,8 +1304,9 @@ 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;
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 03/14] mm: introduce pgtable_has_pmd_leaves()
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 01/14] docs: tmpfs: remove implementation detail reference Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 02/14] mm: shmem: shmem_getattr(): set blksize to highest supported THP order Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 04/14] drivers: dax: use pgtable_has_pmd_leaves() Luiz Capitulino
` (10 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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 8c093c119e5a..4c00cf53e183 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>
@@ -2313,6 +2314,21 @@ 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 /* !__ASSEMBLER__ */
#if !defined(MAX_POSSIBLE_PHYSMEM_BITS) && !defined(CONFIG_64BIT)
diff --git a/mm/memory.c b/mm/memory.c
index 56b244552f13..d6540d6d4ef9 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 711f821f7b3c..dcc072db4558 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -2699,6 +2699,7 @@ 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);
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 04/14] drivers: dax: use pgtable_has_pmd_leaves()
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (2 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 03/14] mm: introduce pgtable_has_pmd_leaves() Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 05/14] drivers: nvdimm: " Luiz Capitulino
` (9 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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;
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 05/14] drivers: nvdimm: use pgtable_has_pmd_leaves()
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (3 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 04/14] drivers: dax: use pgtable_has_pmd_leaves() Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 06/14] mm: debug_vm_pgtable: " Luiz Capitulino
` (8 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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;
}
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 06/14] mm: debug_vm_pgtable: use pgtable_has_pmd_leaves()
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (4 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 05/14] drivers: nvdimm: " Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 07/14] mm: shmem: allow THP support determination at folio allocation time Luiz Capitulino
` (7 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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 2875fd22d7bb..25038b74c7bc 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_ARCH_HAS_PTE_PROTNONE))
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_HAS_PMD_SOFTLEAVES))
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);
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 07/14] mm: shmem: allow THP support determination at folio allocation time
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (5 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 06/14] mm: debug_vm_pgtable: " Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 08/14] s390: move has_transparent_hugepage() out of THP guard Luiz Capitulino
` (6 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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.
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
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 19534e21b61f..68ae606b5c4c 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;
@@ -1305,6 +1305,8 @@ 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);
@@ -4589,8 +4591,7 @@ 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;
@@ -5385,7 +5386,7 @@ 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 */
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 08/14] s390: move has_transparent_hugepage() out of THP guard
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (6 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 07/14] mm: shmem: allow THP support determination at folio allocation time Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 09/14] powerpc: " Luiz Capitulino
` (5 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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 e882663a58e7..5aa8f621df04 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1825,13 +1825,13 @@ 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)
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 09/14] powerpc: move has_transparent_hugepage() out of THP guard
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (7 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 08/14] s390: move has_transparent_hugepage() out of THP guard Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 10/14] mips: " Luiz Capitulino
` (4 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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 f4db7d7fbd5c..2a795f6d9263 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 {
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 10/14] mips: move has_transparent_hugepage() out of THP guard
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (8 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 09/14] powerpc: " Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 11/14] x86: " Luiz Capitulino
` (3 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 11/14] x86: move has_transparent_hugepage() out of THP guard
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (9 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 10/14] mips: " Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 12/14] treewide: introduce arch_has_pmd_leaves() Luiz Capitulino
` (2 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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 8e0018fadd14..3c62b33147fa 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);
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 12/14] treewide: introduce arch_has_pmd_leaves()
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (10 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 11/14] x86: " Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 13/14] mm: replace thp_disabled_by_hw() with pgtable_has_pmd_leaves() Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 14/14] mm: thp: always enable mTHP support Luiz Capitulino
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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 2a795f6d9263..41166d44fa75 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 5aa8f621df04..24ee90c7e9bf 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1827,8 +1827,8 @@ 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 3c62b33147fa..3c6a641e6c21 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 4c00cf53e183..d571d161a84b 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -2344,8 +2344,8 @@ 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 04e8a6b55343..3f3a929e3069 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1010,7 +1010,7 @@ 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 d6540d6d4ef9..b0d3a8a8a25d 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);
}
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 13/14] mm: replace thp_disabled_by_hw() with pgtable_has_pmd_leaves()
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (11 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 12/14] treewide: introduce arch_has_pmd_leaves() Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
2026-07-24 1:34 ` [PATCH v6 14/14] mm: thp: always enable mTHP support Luiz Capitulino
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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 c745f7ad2298..525acea2eb59 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,
@@ -383,12 +382,6 @@ 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_vmaflags(struct file *filp, unsigned long addr,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3f3a929e3069..78dd16513a11 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -136,7 +136,7 @@ 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. */
@@ -1010,10 +1010,8 @@ 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 b0d3a8a8a25d..f39d9383494e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5576,7 +5576,7 @@ 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 68ae606b5c4c..4d2e1b91ec26 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1832,7 +1832,7 @@ 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,
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread* [PATCH v6 14/14] mm: thp: always enable mTHP support
2026-07-24 1:34 [PATCH v6 00/14] mm: thp: always enable mTHP support Luiz Capitulino
` (12 preceding siblings ...)
2026-07-24 1:34 ` [PATCH v6 13/14] mm: replace thp_disabled_by_hw() with pgtable_has_pmd_leaves() Luiz Capitulino
@ 2026-07-24 1:34 ` Luiz Capitulino
13 siblings, 0 replies; 15+ messages in thread
From: Luiz Capitulino @ 2026-07-24 1:34 UTC (permalink / raw)
To: linux-kernel, linux-mm, david, baolin.wang, ziy, lance.yang
Cc: corbet, tsbogend, maddy, mpe, agordeev, gerald.schaefer, hca, gor,
x86, tglx, mingo, bp, ira.weiny, hughd, dave.hansen, djbw,
vishal.l.verma, dave.jiang, akpm, yintirui, ljs, dev.jain
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
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
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 78dd16513a11..385a305e7af6 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -129,6 +129,15 @@ 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;
@@ -136,7 +145,7 @@ 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. */
@@ -874,7 +883,7 @@ 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);
@@ -896,6 +905,15 @@ 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);
@@ -1010,9 +1028,6 @@ 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 4d2e1b91ec26..008df558af23 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1830,16 +1830,19 @@ 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
@@ -1853,7 +1856,7 @@ 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);
@@ -1864,6 +1867,7 @@ 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;
}
@@ -5395,7 +5399,7 @@ 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;
--
2.55.0
^ permalink raw reply related [flat|nested] 15+ messages in thread