From: Yulei Zhang <yuleixzhang@xxxxxxxxxxx>
A dmem huge page is ultimately not a transparent huge page. As we
decided to use pmd_special() to distinguish dmem-pmd from thp-pmd,
we should make some slightly different semantics between pmd_special()
and pmd_trans_huge(), just as pmd_devmap() in upstream. This distinction
is especially important in some mm-core paths such as zap_pmd_range().
Explicitly mark the pmd_trans_huge() helpers that dmem needs by adding
pmd_special() checks. This method could be reused in many mm-core paths.
Signed-off-by: Chen Zhuo <sagazchen@xxxxxxxxxxx>
Signed-off-by: Yulei Zhang <yuleixzhang@xxxxxxxxxxx>
---
arch/x86/include/asm/pgtable.h | 10 +++++++++-
include/linux/pgtable.h | 5 +++++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index ea4554a728bc..e29601cad384 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -260,7 +260,7 @@ static inline int pmd_large(pmd_t pte)
/* NOTE: when predicate huge page, consider also pmd_devmap, or use pmd_large */
static inline int pmd_trans_huge(pmd_t pmd)
{
- return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
+ return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP|_PAGE_DMEM)) == _PAGE_PSE;
}
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
@@ -276,6 +276,14 @@ static inline int has_transparent_hugepage(void)
return boot_cpu_has(X86_FEATURE_PSE);
}
+#ifdef CONFIG_ARCH_HAS_PTE_DMEM
+static inline int pmd_special(pmd_t pmd)
+{
+ return (pmd_val(pmd) & (_PAGE_SPECIAL | _PAGE_DMEM)) ==
+ (_PAGE_SPECIAL | _PAGE_DMEM);
+}
+#endif
+
#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
static inline int pmd_devmap(pmd_t pmd)
{
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 45d4c4a3e519..1fe8546c0a7c 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1134,6 +1134,11 @@ static inline pmd_t pmd_mkdmem(pmd_t pmd)
{
return pmd;
}
+
+static inline int pmd_special(pmd_t pmd)
+{
+ return 0;
+}
#endif
#ifndef pmd_read_atomic
--
2.28.0
