Introduce two more sub-options for PGTABLE_HAS_HUGE_LEAVES:
- PGTABLE_HAS_PMD_LEAVES: set when there can be PMD mappings
- PGTABLE_HAS_PUD_LEAVES: set when there can be PUD mappings
It will help to identify whether the current build may only want PMD
helpers but not PUD ones, as these sub-options will also check against the
arch support over HAVE_ARCH_TRANSPARENT_HUGEPAGE[_PUD].
Note that having them depend on HAVE_ARCH_TRANSPARENT_HUGEPAGE[_PUD] is
still some intermediate step. The best way is to have an option say
"whether arch XXX supports PMD/PUD mappings" and so on. However let's
leave that for later as that's the easy part. So far, we use these options
to stably detect per-arch huge mapping support.
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
include/linux/huge_mm.h | 10 +++++++---
mm/Kconfig | 6 ++++++
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 711632df7edf..37482c8445d1 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -96,14 +96,18 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr;
#define thp_vma_allowable_order(vma, vm_flags, tva_flags, order) \
(!!thp_vma_allowable_orders(vma, vm_flags, tva_flags, BIT(order)))
-#ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES
-#define HPAGE_PMD_SHIFT PMD_SHIFT
+#ifdef CONFIG_PGTABLE_HAS_PUD_LEAVES
#define HPAGE_PUD_SHIFT PUD_SHIFT
#else
-#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
#define HPAGE_PUD_SHIFT ({ BUILD_BUG(); 0; })
#endif
+#ifdef CONFIG_PGTABLE_HAS_PMD_LEAVES
+#define HPAGE_PMD_SHIFT PMD_SHIFT
+#else
+#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
+#endif
+
#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
#define HPAGE_PMD_MASK (~(HPAGE_PMD_SIZE - 1))
diff --git a/mm/Kconfig b/mm/Kconfig
index 60796402850e..2dbdc088dee8 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -860,6 +860,12 @@ endif # TRANSPARENT_HUGEPAGE
config PGTABLE_HAS_HUGE_LEAVES
def_bool TRANSPARENT_HUGEPAGE || HUGETLB_PAGE
+config PGTABLE_HAS_PMD_LEAVES
+ def_bool HAVE_ARCH_TRANSPARENT_HUGEPAGE && PGTABLE_HAS_HUGE_LEAVES
+
+config PGTABLE_HAS_PUD_LEAVES
+ def_bool HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD && PGTABLE_HAS_HUGE_LEAVES
+
#
# UP and nommu archs use km based percpu allocator
#
--
2.45.0
