[v2 PATCH 1/7] mm: memory: add orig_pmd to struct vm_fault

Yang Shi
2021-04-13T21:24:37Z

Add orig_pmd to struct vm_fault so the "orig_pmd" parameter used by huge page
fault could be removed, just like its PTE counterpart does.

Signed-off-by: Yang Shi <shy828301@gmail.com>
---
include/linux/huge_mm.h | 9 ++++-----
include/linux/mm.h | 3 +++
mm/huge_memory.c | 9 ++++++---
mm/memory.c | 26 +++++++++++++-------------
4 files changed, 26 insertions(+), 21 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 9626fda5efce..3b38070f4337 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -11,7 +11,7 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf);
int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
struct vm_area_struct *vma);
-void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd);
+void huge_pmd_set_accessed(struct vm_fault *vmf);
int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pud_t *dst_pud, pud_t *src_pud, unsigned long addr,
struct vm_area_struct *vma);
@@ -24,7 +24,7 @@ static inline void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
}
#endif

-vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd);
+vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf);
struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
unsigned long addr, pmd_t *pmd,
unsigned int flags);
@@ -283,7 +283,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
pud_t *pud, int flags, struct dev_pagemap **pgmap);

-vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd);
+vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf);

extern struct page *huge_zero_page;

@@ -429,8 +429,7 @@ static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
return NULL;
}

-static inline vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf,
- pmd_t orig_pmd)
+static inline vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
{
return 0;
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 25b9041f9925..9c5856f8cc81 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -547,6 +547,9 @@ struct vm_fault {
* the 'address'
*/
pte_t orig_pte; /* Value of PTE at the time of fault */
+ pmd_t orig_pmd; /* Value of PMD at the time of fault,
+ * used by PMD fault only.
+ */

struct page *cow_page; /* Page handler may use for COW fault */
struct page *page; /* ->fault handlers should return a
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 63ed6b25deaa..35cac4aeaf68 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1251,11 +1251,12 @@ void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
}
#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */

-void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd)
+void huge_pmd_set_accessed(struct vm_fault *vmf)
{
pmd_t entry;
unsigned long haddr;
bool write = vmf->flags & FAULT_FLAG_WRITE;
+ pmd_t orig_pmd = vmf->orig_pmd;

vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
if (unlikely(!pmd_same(*vmf->pmd, orig_pmd)))
@@ -1272,11 +1273,12 @@ void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd)
spin_unlock(vmf->ptl);
}

-vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
+vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct page *page;
unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
+ pmd_t orig_pmd = vmf->orig_pmd;

vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd);
VM_BUG_ON_VMA(!vma->anon_vma, vma);
@@ -1412,9 +1414,10 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
}

/* NUMA hinting page fault entry point for trans huge pmds */
-vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
+vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
+ pmd_t pmd = vmf->orig_pmd;
struct anon_vma *anon_vma = NULL;
struct page *page;
unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
diff --git a/mm/memory.c b/mm/memory.c
index 4e358601c5d6..e0cbffeceb0b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4232,12 +4232,12 @@ static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf)
}

/* `inline' is required to avoid gcc 4.1.2 build error */
-static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd)
+static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf)
{
if (vma_is_anonymous(vmf->vma)) {
- if (userfaultfd_huge_pmd_wp(vmf->vma, orig_pmd))
+ if (userfaultfd_huge_pmd_wp(vmf->vma, vmf->orig_pmd))
return handle_userfault(vmf, VM_UFFD_WP);
- return do_huge_pmd_wp_page(vmf, orig_pmd);
+ return do_huge_pmd_wp_page(vmf);
}
if (vmf->vma->vm_ops->huge_fault) {
vm_fault_t ret = vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD);
@@ -4464,26 +4464,26 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
if (!(ret & VM_FAULT_FALLBACK))
return ret;
} else {
- pmd_t orig_pmd = *vmf.pmd;
+ vmf.orig_pmd = *vmf.pmd;

barrier();
- if (unlikely(is_swap_pmd(orig_pmd))) {
+ if (unlikely(is_swap_pmd(vmf.orig_pmd))) {
VM_BUG_ON(thp_migration_supported() &&
- !is_pmd_migration_entry(orig_pmd));
- if (is_pmd_migration_entry(orig_pmd))
+ !is_pmd_migration_entry(vmf.orig_pmd));
+ if (is_pmd_migration_entry(vmf.orig_pmd))
pmd_migration_entry_wait(mm, vmf.pmd);
return 0;
}
- if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
- if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
- return do_huge_pmd_numa_page(&vmf, orig_pmd);
+ if (pmd_trans_huge(vmf.orig_pmd) || pmd_devmap(vmf.orig_pmd)) {
+ if (pmd_protnone(vmf.orig_pmd) && vma_is_accessible(vma))
+ return do_huge_pmd_numa_page(&vmf);

- if (dirty && !pmd_write(orig_pmd)) {
- ret = wp_huge_pmd(&vmf, orig_pmd);
+ if (dirty && !pmd_write(vmf.orig_pmd)) {
+ ret = wp_huge_pmd(&vmf);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
} else {
- huge_pmd_set_accessed(&vmf, orig_pmd);
+ huge_pmd_set_accessed(&vmf);
return 0;
}
}
--
2.26.2