[PATCH v5 06/11] thp: change split_huge_page_pmd() interface

Kirill A. Shutemov
2012-11-07T15:01:13Z

From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>

Pass vma instead of mm and add address parameter.

In most cases we already have vma on the stack. We provides
split_huge_page_pmd_mm() for few cases when we have mm, but not vma.

This change is preparation to huge zero pmd splitting implementation.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
Documentation/vm/transhuge.txt | 4 ++--
arch/x86/kernel/vm86_32.c | 2 +-
fs/proc/task_mmu.c | 2 +-
include/linux/huge_mm.h | 14 ++++++++++----
mm/huge_memory.c | 24 +++++++++++++++++++-----
mm/memory.c | 4 ++--
mm/mempolicy.c | 2 +-
mm/mprotect.c | 2 +-
mm/mremap.c | 2 +-
mm/pagewalk.c | 2 +-
10 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/Documentation/vm/transhuge.txt b/Documentation/vm/transhuge.txt
index f734bb2..677a599 100644
--- a/Documentation/vm/transhuge.txt
+++ b/Documentation/vm/transhuge.txt
@@ -276,7 +276,7 @@ unaffected. libhugetlbfs will also work fine as usual.
== Graceful fallback ==

Code walking pagetables but unware about huge pmds can simply call
-split_huge_page_pmd(mm, pmd) where the pmd is the one returned by
+split_huge_page_pmd(vma, pmd, addr) where the pmd is the one returned by
pmd_offset. It's trivial to make the code transparent hugepage aware
by just grepping for "pmd_offset" and adding split_huge_page_pmd where
missing after pmd_offset returns the pmd. Thanks to the graceful
@@ -299,7 +299,7 @@ diff --git a/mm/mremap.c b/mm/mremap.c
return NULL;

pmd = pmd_offset(pud, addr);
-+ split_huge_page_pmd(mm, pmd);
++ split_huge_page_pmd(vma, pmd, addr);
if (pmd_none_or_clear_bad(pmd))
return NULL;

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 5c9687b..1dfe69c 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -182,7 +182,7 @@ static void mark_screen_rdonly(struct mm_struct *mm)
if (pud_none_or_clear_bad(pud))
goto out;
pmd = pmd_offset(pud, 0xA0000);
- split_huge_page_pmd(mm, pmd);
+ split_huge_page_pmd_mm(mm, 0xA0000, pmd);
if (pmd_none_or_clear_bad(pmd))
goto out;
pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 90c63f9..291a0d1 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -643,7 +643,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
spinlock_t *ptl;
struct page *page;

- split_huge_page_pmd(walk->mm, pmd);
+ split_huge_page_pmd(vma, addr, pmd);
if (pmd_trans_unstable(pmd))
return 0;

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index b31cb7d..856f080 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -91,12 +91,14 @@ extern int handle_pte_fault(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
pte_t *pte, pmd_t *pmd, unsigned int flags);
extern int split_huge_page(struct page *page);
-extern void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd);
-#define split_huge_page_pmd(__mm, __pmd) \
+extern void __split_huge_page_pmd(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmd);
+#define split_huge_page_pmd(__vma, __address, __pmd) \
do { \
pmd_t *____pmd = (__pmd); \
if (unlikely(pmd_trans_huge(*____pmd))) \
- __split_huge_page_pmd(__mm, ____pmd); \
+ __split_huge_page_pmd(__vma, __address, \
+ ____pmd); \
} while (0)
#define wait_split_huge_page(__anon_vma, __pmd) \
do { \
@@ -106,6 +108,8 @@ extern void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd);
BUG_ON(pmd_trans_splitting(*____pmd) || \
pmd_trans_huge(*____pmd)); \
} while (0)
+extern void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
+ pmd_t *pmd);
#if HPAGE_PMD_ORDER > MAX_ORDER
#error "hugepages can't be allocated by the buddy allocator"
#endif
@@ -173,10 +177,12 @@ static inline int split_huge_page(struct page *page)
{
return 0;
}
-#define split_huge_page_pmd(__mm, __pmd) \
+#define split_huge_page_pmd(__vma, __address, __pmd) \
do { } while (0)
#define wait_split_huge_page(__anon_vma, __pmd) \
do { } while (0)
+#define split_huge_page_pmd_mm(__mm, __address, __pmd) \
+ do { } while (0)
#define compound_trans_head(page) compound_head(page)
static inline int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 05490b3..90e651c 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2509,19 +2509,23 @@ static int khugepaged(void *none)
return 0;
}

-void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd)
+void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmd)
{
struct page *page;
+ unsigned long haddr = address & HPAGE_PMD_MASK;

- spin_lock(&mm->page_table_lock);
+ BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE);
+
+ spin_lock(&vma->vm_mm->page_table_lock);
if (unlikely(!pmd_trans_huge(*pmd))) {
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&vma->vm_mm->page_table_lock);
return;
}
page = pmd_page(*pmd);
VM_BUG_ON(!page_count(page));
get_page(page);
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&vma->vm_mm->page_table_lock);

split_huge_page(page);

@@ -2529,6 +2533,16 @@ void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd)
BUG_ON(pmd_trans_huge(*pmd));
}

+void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
+ pmd_t *pmd)
+{
+ struct vm_area_struct *vma;
+
+ vma = find_vma(mm, address);
+ BUG_ON(vma == NULL);
+ split_huge_page_pmd(vma, address, pmd);
+}
+
static void split_huge_page_address(struct mm_struct *mm,
unsigned long address)
{
@@ -2553,7 +2567,7 @@ static void split_huge_page_address(struct mm_struct *mm,
* Caller holds the mmap_sem write mode, so a huge pmd cannot
* materialize from under us.
*/
- split_huge_page_pmd(mm, pmd);
+ split_huge_page_pmd_mm(mm, address, pmd);
}

void __vma_adjust_trans_huge(struct vm_area_struct *vma,
diff --git a/mm/memory.c b/mm/memory.c
index 6edc030..6017e23 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1243,7 +1243,7 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
BUG();
}
#endif
- split_huge_page_pmd(vma->vm_mm, pmd);
+ split_huge_page_pmd(vma, addr, pmd);
} else if (zap_huge_pmd(tlb, vma, pmd, addr))
goto next;
/* fall through */
@@ -1512,7 +1512,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
}
if (pmd_trans_huge(*pmd)) {
if (flags & FOLL_SPLIT) {
- split_huge_page_pmd(mm, pmd);
+ split_huge_page_pmd(vma, address, pmd);
goto split_fallthrough;
}
spin_lock(&mm->page_table_lock);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d04a8a5..b68061e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -511,7 +511,7 @@ static inline int check_pmd_range(struct vm_area_struct *vma, pud_t *pud,
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
- split_huge_page_pmd(vma->vm_mm, pmd);
+ split_huge_page_pmd(vma, addr, pmd);
if (pmd_none_or_trans_huge_or_clear_bad(pmd))
continue;
if (check_pte_range(vma, pmd, addr, next, nodes,
diff --git a/mm/mprotect.c b/mm/mprotect.c
index a409926..e8c3938 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -90,7 +90,7 @@ static inline void change_pmd_range(struct vm_area_struct *vma, pud_t *pud,
next = pmd_addr_end(addr, end);
if (pmd_trans_huge(*pmd)) {
if (next - addr != HPAGE_PMD_SIZE)
- split_huge_page_pmd(vma->vm_mm, pmd);
+ split_huge_page_pmd(vma, addr, pmd);
else if (change_huge_pmd(vma, pmd, addr, newprot))
continue;
/* fall through */
diff --git a/mm/mremap.c b/mm/mremap.c
index 1b61c2d..eabb24d 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -182,7 +182,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
need_flush = true;
continue;
} else if (!err) {
- split_huge_page_pmd(vma->vm_mm, old_pmd);
+ split_huge_page_pmd(vma, old_addr, old_pmd);
}
VM_BUG_ON(pmd_trans_huge(*old_pmd));
}
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 6c118d0..35aa294 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -58,7 +58,7 @@ again:
if (!walk->pte_entry)
continue;

- split_huge_page_pmd(walk->mm, pmd);
+ split_huge_page_pmd_mm(walk->mm, addr, pmd);
if (pmd_none_or_trans_huge_or_clear_bad(pmd))
goto again;
err = walk_pte_range(pmd, addr, next, walk);
--
1.7.7.6