Re: [PATCHv5 09/28] thp: rename split_huge_page_pmd() to split_huge_pmd()

Vlastimil Babka <vbabka@xxxxxxx> · Fri, 15 May 2015 15:08:48 +0200

On 04/23/2015 11:03 PM, Kirill A. Shutemov wrote:
We are going to decouple splitting THP PMD from splitting underlying
compound page.

This patch renames split_huge_page_pmd*() functions to split_huge_pmd*()
to reflect the fact that it doesn't imply page splitting, only PMD.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Tested-by: Sasha Levin <sasha.levin@xxxxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

---
  arch/powerpc/mm/subpage-prot.c |  2 +-
  arch/x86/kernel/vm86_32.c      |  6 +++++-
  include/linux/huge_mm.h        |  8 ++------
  mm/gup.c                       |  2 +-
  mm/huge_memory.c               | 32 +++++++++++---------------------
  mm/madvise.c                   |  2 +-
  mm/memory.c                    |  2 +-
  mm/mempolicy.c                 |  2 +-
  mm/mprotect.c                  |  2 +-
  mm/mremap.c                    |  2 +-
  mm/pagewalk.c                  |  2 +-
  11 files changed, 26 insertions(+), 36 deletions(-)

diff --git a/arch/powerpc/mm/subpage-prot.c b/arch/powerpc/mm/subpage-prot.c
index fa9fb5b4c66c..d5543514c1df 100644
--- a/arch/powerpc/mm/subpage-prot.c
+++ b/arch/powerpc/mm/subpage-prot.c
@@ -135,7 +135,7 @@ static int subpage_walk_pmd_entry(pmd_t *pmd, unsigned long addr,
  				  unsigned long end, struct mm_walk *walk)
  {
  	struct vm_area_struct *vma = walk->vma;
-	split_huge_page_pmd(vma, addr, pmd);
+	split_huge_pmd(vma, pmd, addr);
  	return 0;
  }

diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index e8edcf52e069..883160599965 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -182,7 +182,11 @@ 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(mm, 0xA0000, pmd);
+
+	if (pmd_trans_huge(*pmd)) {
+		struct vm_area_struct *vma = find_vma(mm, 0xA0000);
+		split_huge_pmd(vma, pmd, 0xA0000);
+	}
  	if (pmd_none_or_clear_bad(pmd))
  		goto out;
  	pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl);
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 44a840a53974..34bbf769d52e 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -104,7 +104,7 @@ static inline int split_huge_page(struct page *page)
  }
  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)			\
+#define split_huge_pmd(__vma, __pmd, __address)				\
  	do {								\
  		pmd_t *____pmd = (__pmd);				\
  		if (unlikely(pmd_trans_huge(*____pmd)))			\
@@ -119,8 +119,6 @@ extern void __split_huge_page_pmd(struct vm_area_struct *vma,
  		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
@@ -187,11 +185,9 @@ static inline int split_huge_page(struct page *page)
  {
  	return 0;
  }
-#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)	\
+#define split_huge_pmd(__vma, __pmd, __address)	\
  	do { } while (0)
  static inline int hugepage_madvise(struct vm_area_struct *vma,
  				   unsigned long *vm_flags, int advice)
diff --git a/mm/gup.c b/mm/gup.c
index 7334eb24f414..19e01f156abb 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -220,7 +220,7 @@ struct page *follow_page_mask(struct vm_area_struct *vma,
  		if (is_huge_zero_page(page)) {
  			spin_unlock(ptl);
  			ret = 0;
-			split_huge_page_pmd(vma, address, pmd);
+			split_huge_pmd(vma, pmd, address);
  		} else {
  			get_page(page);
  			spin_unlock(ptl);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ffc30e4462c1..ccbfacf07160 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1136,13 +1136,13 @@ alloc:

  	if (unlikely(!new_page)) {
  		if (!page) {
-			split_huge_page_pmd(vma, address, pmd);
+			split_huge_pmd(vma, pmd, address);
  			ret |= VM_FAULT_FALLBACK;
  		} else {
  			ret = do_huge_pmd_wp_page_fallback(mm, vma, address,
  					pmd, orig_pmd, page, haddr);
  			if (ret & VM_FAULT_OOM) {
-				split_huge_page(page);
+				split_huge_pmd(vma, pmd, address);
  				ret |= VM_FAULT_FALLBACK;
  			}
  			put_user_huge_page(page);
@@ -1155,10 +1155,10 @@ alloc:
  					&memcg, true))) {
  		put_page(new_page);
  		if (page) {
-			split_huge_page(page);
+			split_huge_pmd(vma, pmd, address);
  			put_user_huge_page(page);
  		} else
-			split_huge_page_pmd(vma, address, pmd);
+			split_huge_pmd(vma, pmd, address);
  		ret |= VM_FAULT_FALLBACK;
  		count_vm_event(THP_FAULT_FALLBACK);
  		goto out;
@@ -2985,17 +2985,7 @@ again:
  		goto again;
  }

-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,
+static void split_huge_pmd_address(struct vm_area_struct *vma,
  				    unsigned long address)
  {
  	pgd_t *pgd;
@@ -3004,7 +2994,7 @@ static void split_huge_page_address(struct mm_struct *mm,

  	VM_BUG_ON(!(address & ~HPAGE_PMD_MASK));

-	pgd = pgd_offset(mm, address);
+	pgd = pgd_offset(vma->vm_mm, address);
  	if (!pgd_present(*pgd))
  		return;

@@ -3013,13 +3003,13 @@ static void split_huge_page_address(struct mm_struct *mm,
  		return;

  	pmd = pmd_offset(pud, address);
-	if (!pmd_present(*pmd))
+	if (!pmd_present(*pmd) || !pmd_trans_huge(*pmd))
  		return;
  	/*
  	 * Caller holds the mmap_sem write mode, so a huge pmd cannot
  	 * materialize from under us.
  	 */
-	split_huge_page_pmd_mm(mm, address, pmd);
+	__split_huge_page_pmd(vma, address, pmd);
  }

  void __vma_adjust_trans_huge(struct vm_area_struct *vma,
@@ -3035,7 +3025,7 @@ void __vma_adjust_trans_huge(struct vm_area_struct *vma,
  	if (start & ~HPAGE_PMD_MASK &&
  	    (start & HPAGE_PMD_MASK) >= vma->vm_start &&
  	    (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
-		split_huge_page_address(vma->vm_mm, start);
+		split_huge_pmd_address(vma, start);

  	/*
  	 * If the new end address isn't hpage aligned and it could
@@ -3045,7 +3035,7 @@ void __vma_adjust_trans_huge(struct vm_area_struct *vma,
  	if (end & ~HPAGE_PMD_MASK &&
  	    (end & HPAGE_PMD_MASK) >= vma->vm_start &&
  	    (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
-		split_huge_page_address(vma->vm_mm, end);
+		split_huge_pmd_address(vma, end);

  	/*
  	 * If we're also updating the vma->vm_next->vm_start, if the new
@@ -3059,6 +3049,6 @@ void __vma_adjust_trans_huge(struct vm_area_struct *vma,
  		if (nstart & ~HPAGE_PMD_MASK &&
  		    (nstart & HPAGE_PMD_MASK) >= next->vm_start &&
  		    (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end)
-			split_huge_page_address(next->vm_mm, nstart);
+			split_huge_pmd_address(next, nstart);
  	}
  }
diff --git a/mm/madvise.c b/mm/madvise.c
index 22b86daf6b94..f5a81ca0dca7 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -281,7 +281,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
  	next = pmd_addr_end(addr, end);
  	if (pmd_trans_huge(*pmd)) {
  		if (next - addr != HPAGE_PMD_SIZE)
-			split_huge_page_pmd(vma, addr, pmd);
+			split_huge_pmd(vma, pmd, addr);
  		else if (!madvise_free_huge_pmd(tlb, vma, pmd, addr))
  			goto next;
  		/* fall through */
diff --git a/mm/memory.c b/mm/memory.c
index 8bbd3f88544b..61e7ed722760 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1201,7 +1201,7 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
  					BUG();
  				}
  #endif
-				split_huge_page_pmd(vma, addr, pmd);
+				split_huge_pmd(vma, pmd, addr);
  			} else if (zap_huge_pmd(tlb, vma, pmd, addr))
  				goto next;
  			/* fall through */
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 8badb84c013e..aac490fdc91f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -493,7 +493,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
  	pte_t *pte;
  	spinlock_t *ptl;

-	split_huge_page_pmd(vma, addr, pmd);
+	split_huge_pmd(vma, pmd, addr);
  	if (pmd_trans_unstable(pmd))
  		return 0;

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 88584838e704..714d2fbbaafd 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -158,7 +158,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma,

  		if (pmd_trans_huge(*pmd)) {
  			if (next - addr != HPAGE_PMD_SIZE)
-				split_huge_page_pmd(vma, addr, pmd);
+				split_huge_pmd(vma, pmd, addr);
  			else {
  				int nr_ptes = change_huge_pmd(vma, pmd, addr,
  						newprot, prot_numa);
diff --git a/mm/mremap.c b/mm/mremap.c
index afa3ab740d8c..3e40ea27edc4 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -208,7 +208,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
  				need_flush = true;
  				continue;
  			} else if (!err) {
-				split_huge_page_pmd(vma, old_addr, old_pmd);
+				split_huge_pmd(vma, old_pmd, old_addr);
  			}
  			VM_BUG_ON(pmd_trans_huge(*old_pmd));
  		}
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 29f2f8b853ae..207244489a68 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -58,7 +58,7 @@ again:
  		if (!walk->pte_entry)
  			continue;

-		split_huge_page_pmd_mm(walk->mm, addr, pmd);
+		split_huge_pmd(walk->vma, pmd, addr);
  		if (pmd_trans_unstable(pmd))
  			goto again;
  		err = walk_pte_range(pmd, addr, next, walk);


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