[PATCH -mm v7 00/13] pagewalk: improve vma handling, apply to new users

[PATCH -mm v7 00/13] pagewalk: improve vma handling, apply to new users

[Naoya Horiguchi]

This series is ver.7 of page table walker patchset.

I apologize about my long delay since previous version (I have moved to
Japan last month and no machine access for a while.)
I just rebased this onto mmotm-2014-11-05-16-01. I had some conflicts but
the resolution was not hard.
Trinity showed no bug at least in my environment.

Thanks,
Naoya Horiguchi

Tree: git@github.com:Naoya-Horiguchi/linux.git
Branch: mmotm-2014-11-05-16-01/page_table_walker.ver7
---
Summary:

Kirill A. Shutemov (1):
      mm: /proc/pid/clear_refs: avoid split_huge_page()

Naoya Horiguchi (12):
      mm/pagewalk: remove pgd_entry() and pud_entry()
      pagewalk: improve vma handling
      pagewalk: add walk_page_vma()
      smaps: remove mem_size_stats->vma and use walk_page_vma()
      clear_refs: remove clear_refs_private->vma and introduce clear_refs_test_walk()
      pagemap: use walk->vma instead of calling find_vma()
      numa_maps: fix typo in gather_hugetbl_stats
      numa_maps: remove numa_maps->vma
      memcg: cleanup preparation for page table walk
      arch/powerpc/mm/subpage-prot.c: use walk->vma and walk_page_vma()
      mempolicy: apply page table walker on queue_pages_range()
      mincore: apply page table walker on do_mincore()

 arch/powerpc/mm/subpage-prot.c |   6 +-
 fs/proc/task_mmu.c             | 206 ++++++++++++++++++-------------------
 include/linux/mm.h             |  22 ++--
 mm/huge_memory.c               |  20 ----
 mm/memcontrol.c                |  49 +++------
 mm/mempolicy.c                 | 228 +++++++++++++++++------------------------
 mm/mincore.c                   | 169 +++++++++++-------------------
 mm/pagewalk.c                  | 228 ++++++++++++++++++++++++-----------------
 8 files changed, 419 insertions(+), 509 deletions(-)

[PATCH -mm v7 00/13] pagewalk: improve vma handling, apply to new users

[Naoya Horiguchi]

This series is ver.7 of page table walker patchset.

I apologize about my long delay since previous version (I have moved to
Japan last month and no machine access for a while.)
I just rebased this onto mmotm-2014-11-05-16-01. I had some conflicts but
the resolution was not hard.
Trinity showed no bug at least in my environment.

Thanks,
Naoya Horiguchi

Tree: git@github.com:Naoya-Horiguchi/linux.git
Branch: mmotm-2014-11-05-16-01/page_table_walker.ver7
---
Summary:

Kirill A. Shutemov (1):
      mm: /proc/pid/clear_refs: avoid split_huge_page()

Naoya Horiguchi (12):
      mm/pagewalk: remove pgd_entry() and pud_entry()
      pagewalk: improve vma handling
      pagewalk: add walk_page_vma()
      smaps: remove mem_size_stats->vma and use walk_page_vma()
      clear_refs: remove clear_refs_private->vma and introduce clear_refs_test_walk()
      pagemap: use walk->vma instead of calling find_vma()
      numa_maps: fix typo in gather_hugetbl_stats
      numa_maps: remove numa_maps->vma
      memcg: cleanup preparation for page table walk
      arch/powerpc/mm/subpage-prot.c: use walk->vma and walk_page_vma()
      mempolicy: apply page table walker on queue_pages_range()
      mincore: apply page table walker on do_mincore()

 arch/powerpc/mm/subpage-prot.c |   6 +-
 fs/proc/task_mmu.c             | 206 ++++++++++++++++++-------------------
 include/linux/mm.h             |  22 ++--
 mm/huge_memory.c               |  20 ----
 mm/memcontrol.c                |  49 +++------
 mm/mempolicy.c                 | 228 +++++++++++++++++------------------------
 mm/mincore.c                   | 169 +++++++++++-------------------
 mm/pagewalk.c                  | 228 ++++++++++++++++++++++++-----------------
 8 files changed, 419 insertions(+), 509 deletions(-)
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[PATCH -mm v7 01/13] mm/pagewalk: remove pgd_entry() and pud_entry()

[Naoya Horiguchi]

Currently no user of page table walker sets ->pgd_entry() or ->pud_entry(),
so checking their existence in each loop is just wasting CPU cycle.
So let's remove it to reduce overhead.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/mm.h | 6 ------
 mm/pagewalk.c      | 9 ++-------
 2 files changed, 2 insertions(+), 13 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/include/linux/mm.h mmotm-2014-11-05-16-01/include/linux/mm.h
index 423024a0d3db..ba964aa0282a 100644
--- mmotm-2014-11-05-16-01.orig/include/linux/mm.h
+++ mmotm-2014-11-05-16-01/include/linux/mm.h
@@ -1120,8 +1120,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
 
 /**
  * mm_walk - callbacks for walk_page_range
- * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
- * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
  *	       this handler is required to be able to handle
  *	       pmd_trans_huge() pmds.  They may simply choose to
@@ -1135,10 +1133,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  * (see walk_page_range for more details)
  */
 struct mm_walk {
-	int (*pgd_entry)(pgd_t *pgd, unsigned long addr,
-			 unsigned long next, struct mm_walk *walk);
-	int (*pud_entry)(pud_t *pud, unsigned long addr,
-	                 unsigned long next, struct mm_walk *walk);
 	int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
 			 unsigned long next, struct mm_walk *walk);
 	int (*pte_entry)(pte_t *pte, unsigned long addr,
diff --git mmotm-2014-11-05-16-01.orig/mm/pagewalk.c mmotm-2014-11-05-16-01/mm/pagewalk.c
index ad83195521f2..5d41393260c8 100644
--- mmotm-2014-11-05-16-01.orig/mm/pagewalk.c
+++ mmotm-2014-11-05-16-01/mm/pagewalk.c
@@ -86,9 +86,7 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 				break;
 			continue;
 		}
-		if (walk->pud_entry)
-			err = walk->pud_entry(pud, addr, next, walk);
-		if (!err && (walk->pmd_entry || walk->pte_entry))
+		if (walk->pmd_entry || walk->pte_entry)
 			err = walk_pmd_range(pud, addr, next, walk);
 		if (err)
 			break;
@@ -234,10 +232,7 @@ int walk_page_range(unsigned long addr, unsigned long end,
 			pgd++;
 			continue;
 		}
-		if (walk->pgd_entry)
-			err = walk->pgd_entry(pgd, addr, next, walk);
-		if (!err &&
-		    (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
+		if (walk->pmd_entry || walk->pte_entry)
 			err = walk_pud_range(pgd, addr, next, walk);
 		if (err)
 			break;
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 01/13] mm/pagewalk: remove pgd_entry() and pud_entry()

[Naoya Horiguchi]

Currently no user of page table walker sets ->pgd_entry() or ->pud_entry(),
so checking their existence in each loop is just wasting CPU cycle.
So let's remove it to reduce overhead.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 include/linux/mm.h | 6 ------
 mm/pagewalk.c      | 9 ++-------
 2 files changed, 2 insertions(+), 13 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/include/linux/mm.h mmotm-2014-11-05-16-01/include/linux/mm.h
index 423024a0d3db..ba964aa0282a 100644
--- mmotm-2014-11-05-16-01.orig/include/linux/mm.h
+++ mmotm-2014-11-05-16-01/include/linux/mm.h
@@ -1120,8 +1120,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
 
 /**
  * mm_walk - callbacks for walk_page_range
- * @pgd_entry: if set, called for each non-empty PGD (top-level) entry
- * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry
  * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry
  *	       this handler is required to be able to handle
  *	       pmd_trans_huge() pmds.  They may simply choose to
@@ -1135,10 +1133,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  * (see walk_page_range for more details)
  */
 struct mm_walk {
-	int (*pgd_entry)(pgd_t *pgd, unsigned long addr,
-			 unsigned long next, struct mm_walk *walk);
-	int (*pud_entry)(pud_t *pud, unsigned long addr,
-	                 unsigned long next, struct mm_walk *walk);
 	int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
 			 unsigned long next, struct mm_walk *walk);
 	int (*pte_entry)(pte_t *pte, unsigned long addr,
diff --git mmotm-2014-11-05-16-01.orig/mm/pagewalk.c mmotm-2014-11-05-16-01/mm/pagewalk.c
index ad83195521f2..5d41393260c8 100644
--- mmotm-2014-11-05-16-01.orig/mm/pagewalk.c
+++ mmotm-2014-11-05-16-01/mm/pagewalk.c
@@ -86,9 +86,7 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 				break;
 			continue;
 		}
-		if (walk->pud_entry)
-			err = walk->pud_entry(pud, addr, next, walk);
-		if (!err && (walk->pmd_entry || walk->pte_entry))
+		if (walk->pmd_entry || walk->pte_entry)
 			err = walk_pmd_range(pud, addr, next, walk);
 		if (err)
 			break;
@@ -234,10 +232,7 @@ int walk_page_range(unsigned long addr, unsigned long end,
 			pgd++;
 			continue;
 		}
-		if (walk->pgd_entry)
-			err = walk->pgd_entry(pgd, addr, next, walk);
-		if (!err &&
-		    (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
+		if (walk->pmd_entry || walk->pte_entry)
 			err = walk_pud_range(pgd, addr, next, walk);
 		if (err)
 			break;
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 02/13] pagewalk: improve vma handling

[Naoya Horiguchi]

Current implementation of page table walker has a fundamental problem
in vma handling, which started when we tried to handle vma(VM_HUGETLB).
Because it's done in pgd loop, considering vma boundary makes code
complicated and bug-prone.

>From the users viewpoint, some user checks some vma-related condition to
determine whether the user really does page walk over the vma.

In order to solve these, this patch moves vma check outside pgd loop and
introduce a new callback ->test_walk().

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
ChangeLog v4:
- avoid walking over the regions where vma is NULL if pte_hole() is
  undefined
- use vma->vm_next instead of repeating find_vma()
- use min() in walk_page_range "outside vma" branch
- fix return value of walk_hugetlb_range()

ChangeLog v3:
- drop walk->skip control
---
 include/linux/mm.h |  15 +++-
 mm/pagewalk.c      | 203 ++++++++++++++++++++++++++++++-----------------------
 2 files changed, 129 insertions(+), 89 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/include/linux/mm.h mmotm-2014-11-05-16-01/include/linux/mm.h
index ba964aa0282a..25a4cf75b575 100644
--- mmotm-2014-11-05-16-01.orig/include/linux/mm.h
+++ mmotm-2014-11-05-16-01/include/linux/mm.h
@@ -1127,10 +1127,16 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
  * @pte_hole: if set, called for each hole at all levels
  * @hugetlb_entry: if set, called for each hugetlb entry
- *		   *Caution*: The caller must hold mmap_sem() if @hugetlb_entry
- * 			      is used.
+ * @test_walk: caller specific callback function to determine whether
+ *             we walk over the current vma or not. A positive returned
+ *             value means "do page table walk over the current vma,"
+ *             and a negative one means "abort current page table walk
+ *             right now." 0 means "skip the current vma."
+ * @mm:        mm_struct representing the target process of page table walk
+ * @vma:       vma currently walked (NULL if walking outside vmas)
+ * @private:   private data for callbacks' usage
  *
- * (see walk_page_range for more details)
+ * (see the comment on walk_page_range() for more details)
  */
 struct mm_walk {
 	int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
@@ -1142,7 +1148,10 @@ struct mm_walk {
 	int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
 			     unsigned long addr, unsigned long next,
 			     struct mm_walk *walk);
+	int (*test_walk)(unsigned long addr, unsigned long next,
+			struct mm_walk *walk);
 	struct mm_struct *mm;
+	struct vm_area_struct *vma;
 	void *private;
 };
 
diff --git mmotm-2014-11-05-16-01.orig/mm/pagewalk.c mmotm-2014-11-05-16-01/mm/pagewalk.c
index 5d41393260c8..d9cc3caae802 100644
--- mmotm-2014-11-05-16-01.orig/mm/pagewalk.c
+++ mmotm-2014-11-05-16-01/mm/pagewalk.c
@@ -59,7 +59,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 			continue;
 
 		split_huge_page_pmd_mm(walk->mm, addr, pmd);
-		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
+		if (pmd_trans_unstable(pmd))
 			goto again;
 		err = walk_pte_range(pmd, addr, next, walk);
 		if (err)
@@ -95,6 +95,32 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 	return err;
 }
 
+static int walk_pgd_range(unsigned long addr, unsigned long end,
+			  struct mm_walk *walk)
+{
+	pgd_t *pgd;
+	unsigned long next;
+	int err = 0;
+
+	pgd = pgd_offset(walk->mm, addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		if (pgd_none_or_clear_bad(pgd)) {
+			if (walk->pte_hole)
+				err = walk->pte_hole(addr, next, walk);
+			if (err)
+				break;
+			continue;
+		}
+		if (walk->pmd_entry || walk->pte_entry)
+			err = walk_pud_range(pgd, addr, next, walk);
+		if (err)
+			break;
+	} while (pgd++, addr = next, addr != end);
+
+	return err;
+}
+
 #ifdef CONFIG_HUGETLB_PAGE
 static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
 				       unsigned long end)
@@ -103,10 +129,10 @@ static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
 	return boundary < end ? boundary : end;
 }
 
-static int walk_hugetlb_range(struct vm_area_struct *vma,
-			      unsigned long addr, unsigned long end,
+static int walk_hugetlb_range(unsigned long addr, unsigned long end,
 			      struct mm_walk *walk)
 {
+	struct vm_area_struct *vma = walk->vma;
 	struct hstate *h = hstate_vma(vma);
 	unsigned long next;
 	unsigned long hmask = huge_page_mask(h);
@@ -119,15 +145,14 @@ static int walk_hugetlb_range(struct vm_area_struct *vma,
 		if (pte && walk->hugetlb_entry)
 			err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
 		if (err)
-			return err;
+			break;
 	} while (addr = next, addr != end);
 
-	return 0;
+	return err;
 }
 
 #else /* CONFIG_HUGETLB_PAGE */
-static int walk_hugetlb_range(struct vm_area_struct *vma,
-			      unsigned long addr, unsigned long end,
+static int walk_hugetlb_range(unsigned long addr, unsigned long end,
 			      struct mm_walk *walk)
 {
 	return 0;
@@ -135,109 +160,115 @@ static int walk_hugetlb_range(struct vm_area_struct *vma,
 
 #endif /* CONFIG_HUGETLB_PAGE */
 
+/*
+ * Decide whether we really walk over the current vma on [@start, @end)
+ * or skip it via the returned value. Return 0 if we do walk over the
+ * current vma, and return 1 if we skip the vma. Negative values means
+ * error, where we abort the current walk.
+ *
+ * Default check (only VM_PFNMAP check for now) is used when the caller
+ * doesn't define test_walk() callback.
+ */
+static int walk_page_test(unsigned long start, unsigned long end,
+			struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
 
+	if (walk->test_walk)
+		return walk->test_walk(start, end, walk);
+
+	/*
+	 * Do not walk over vma(VM_PFNMAP), because we have no valid struct
+	 * page backing a VM_PFNMAP range. See also commit a9ff785e4437.
+	 */
+	if (vma->vm_flags & VM_PFNMAP)
+		return 1;
+	return 0;
+}
+
+static int __walk_page_range(unsigned long start, unsigned long end,
+			struct mm_walk *walk)
+{
+	int err = 0;
+	struct vm_area_struct *vma = walk->vma;
+
+	if (vma && is_vm_hugetlb_page(vma)) {
+		if (walk->hugetlb_entry)
+			err = walk_hugetlb_range(start, end, walk);
+	} else
+		err = walk_pgd_range(start, end, walk);
+
+	return err;
+}
 
 /**
- * walk_page_range - walk a memory map's page tables with a callback
- * @addr: starting address
- * @end: ending address
- * @walk: set of callbacks to invoke for each level of the tree
- *
- * Recursively walk the page table for the memory area in a VMA,
- * calling supplied callbacks. Callbacks are called in-order (first
- * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
- * etc.). If lower-level callbacks are omitted, walking depth is reduced.
+ * walk_page_range - walk page table with caller specific callbacks
  *
- * Each callback receives an entry pointer and the start and end of the
- * associated range, and a copy of the original mm_walk for access to
- * the ->private or ->mm fields.
+ * Recursively walk the page table tree of the process represented by @walk->mm
+ * within the virtual address range [@start, @end). During walking, we can do
+ * some caller-specific works for each entry, by setting up pmd_entry(),
+ * pte_entry(), and/or hugetlb_entry(). If you don't set up for some of these
+ * callbacks, the associated entries/pages are just ignored.
+ * The return values of these callbacks are commonly defined like below:
+ *  - 0  : succeeded to handle the current entry, and if you don't reach the
+ *         end address yet, continue to walk.
+ *  - >0 : succeeded to handle the current entry, and return to the caller
+ *         with caller specific value.
+ *  - <0 : failed to handle the current entry, and return to the caller
+ *         with error code.
  *
- * Usually no locks are taken, but splitting transparent huge page may
- * take page table lock. And the bottom level iterator will map PTE
- * directories from highmem if necessary.
+ * Before starting to walk page table, some callers want to check whether
+ * they really want to walk over the current vma, typically by checking
+ * its vm_flags. walk_page_test() and @walk->test_walk() are used for this
+ * purpose.
  *
- * If any callback returns a non-zero value, the walk is aborted and
- * the return value is propagated back to the caller. Otherwise 0 is returned.
+ * struct mm_walk keeps current values of some common data like vma and pmd,
+ * which are useful for the access from callbacks. If you want to pass some
+ * caller-specific data to callbacks, @walk->private should be helpful.
  *
- * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry
- * is !NULL.
+ * Locking:
+ *   Callers of walk_page_range() and walk_page_vma() should hold
+ *   @walk->mm->mmap_sem, because these function traverse vma list and/or
+ *   access to vma's data.
  */
-int walk_page_range(unsigned long addr, unsigned long end,
+int walk_page_range(unsigned long start, unsigned long end,
 		    struct mm_walk *walk)
 {
-	pgd_t *pgd;
-	unsigned long next;
 	int err = 0;
+	unsigned long next;
+	struct vm_area_struct *vma;
 
-	if (addr >= end)
-		return err;
+	if (start >= end)
+		return -EINVAL;
 
 	if (!walk->mm)
 		return -EINVAL;
 
 	VM_BUG_ON_MM(!rwsem_is_locked(&walk->mm->mmap_sem), walk->mm);
 
-	pgd = pgd_offset(walk->mm, addr);
+	vma = find_vma(walk->mm, start);
 	do {
-		struct vm_area_struct *vma = NULL;
+		if (!vma) { /* after the last vma */
+			walk->vma = NULL;
+			next = end;
+		} else if (start < vma->vm_start) { /* outside vma */
+			walk->vma = NULL;
+			next = min(end, vma->vm_start);
+		} else { /* inside vma */
+			walk->vma = vma;
+			next = min(end, vma->vm_end);
+			vma = vma->vm_next;
 
-		next = pgd_addr_end(addr, end);
-
-		/*
-		 * This function was not intended to be vma based.
-		 * But there are vma special cases to be handled:
-		 * - hugetlb vma's
-		 * - VM_PFNMAP vma's
-		 */
-		vma = find_vma(walk->mm, addr);
-		if (vma) {
-			/*
-			 * There are no page structures backing a VM_PFNMAP
-			 * range, so do not allow split_huge_page_pmd().
-			 */
-			if ((vma->vm_start <= addr) &&
-			    (vma->vm_flags & VM_PFNMAP)) {
-				next = vma->vm_end;
-				pgd = pgd_offset(walk->mm, next);
+			err = walk_page_test(start, next, walk);
+			if (err > 0)
 				continue;
-			}
-			/*
-			 * Handle hugetlb vma individually because pagetable
-			 * walk for the hugetlb page is dependent on the
-			 * architecture and we can't handled it in the same
-			 * manner as non-huge pages.
-			 */
-			if (walk->hugetlb_entry && (vma->vm_start <= addr) &&
-			    is_vm_hugetlb_page(vma)) {
-				if (vma->vm_end < next)
-					next = vma->vm_end;
-				/*
-				 * Hugepage is very tightly coupled with vma,
-				 * so walk through hugetlb entries within a
-				 * given vma.
-				 */
-				err = walk_hugetlb_range(vma, addr, next, walk);
-				if (err)
-					break;
-				pgd = pgd_offset(walk->mm, next);
-				continue;
-			}
-		}
-
-		if (pgd_none_or_clear_bad(pgd)) {
-			if (walk->pte_hole)
-				err = walk->pte_hole(addr, next, walk);
-			if (err)
+			if (err < 0)
 				break;
-			pgd++;
-			continue;
 		}
-		if (walk->pmd_entry || walk->pte_entry)
-			err = walk_pud_range(pgd, addr, next, walk);
+		if (walk->vma || walk->pte_hole)
+			err = __walk_page_range(start, next, walk);
 		if (err)
 			break;
-		pgd++;
-	} while (addr = next, addr < end);
-
+	} while (start = next, start < end);
 	return err;
 }
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 02/13] pagewalk: improve vma handling

[Naoya Horiguchi]

Current implementation of page table walker has a fundamental problem
in vma handling, which started when we tried to handle vma(VM_HUGETLB).
Because it's done in pgd loop, considering vma boundary makes code
complicated and bug-prone.

>From the users viewpoint, some user checks some vma-related condition to
determine whether the user really does page walk over the vma.

In order to solve these, this patch moves vma check outside pgd loop and
introduce a new callback ->test_walk().

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
ChangeLog v4:
- avoid walking over the regions where vma is NULL if pte_hole() is
  undefined
- use vma->vm_next instead of repeating find_vma()
- use min() in walk_page_range "outside vma" branch
- fix return value of walk_hugetlb_range()

ChangeLog v3:
- drop walk->skip control
---
 include/linux/mm.h |  15 +++-
 mm/pagewalk.c      | 203 ++++++++++++++++++++++++++++++-----------------------
 2 files changed, 129 insertions(+), 89 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/include/linux/mm.h mmotm-2014-11-05-16-01/include/linux/mm.h
index ba964aa0282a..25a4cf75b575 100644
--- mmotm-2014-11-05-16-01.orig/include/linux/mm.h
+++ mmotm-2014-11-05-16-01/include/linux/mm.h
@@ -1127,10 +1127,16 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
  * @pte_entry: if set, called for each non-empty PTE (4th-level) entry
  * @pte_hole: if set, called for each hole at all levels
  * @hugetlb_entry: if set, called for each hugetlb entry
- *		   *Caution*: The caller must hold mmap_sem() if @hugetlb_entry
- * 			      is used.
+ * @test_walk: caller specific callback function to determine whether
+ *             we walk over the current vma or not. A positive returned
+ *             value means "do page table walk over the current vma,"
+ *             and a negative one means "abort current page table walk
+ *             right now." 0 means "skip the current vma."
+ * @mm:        mm_struct representing the target process of page table walk
+ * @vma:       vma currently walked (NULL if walking outside vmas)
+ * @private:   private data for callbacks' usage
  *
- * (see walk_page_range for more details)
+ * (see the comment on walk_page_range() for more details)
  */
 struct mm_walk {
 	int (*pmd_entry)(pmd_t *pmd, unsigned long addr,
@@ -1142,7 +1148,10 @@ struct mm_walk {
 	int (*hugetlb_entry)(pte_t *pte, unsigned long hmask,
 			     unsigned long addr, unsigned long next,
 			     struct mm_walk *walk);
+	int (*test_walk)(unsigned long addr, unsigned long next,
+			struct mm_walk *walk);
 	struct mm_struct *mm;
+	struct vm_area_struct *vma;
 	void *private;
 };
 
diff --git mmotm-2014-11-05-16-01.orig/mm/pagewalk.c mmotm-2014-11-05-16-01/mm/pagewalk.c
index 5d41393260c8..d9cc3caae802 100644
--- mmotm-2014-11-05-16-01.orig/mm/pagewalk.c
+++ mmotm-2014-11-05-16-01/mm/pagewalk.c
@@ -59,7 +59,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 			continue;
 
 		split_huge_page_pmd_mm(walk->mm, addr, pmd);
-		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
+		if (pmd_trans_unstable(pmd))
 			goto again;
 		err = walk_pte_range(pmd, addr, next, walk);
 		if (err)
@@ -95,6 +95,32 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
 	return err;
 }
 
+static int walk_pgd_range(unsigned long addr, unsigned long end,
+			  struct mm_walk *walk)
+{
+	pgd_t *pgd;
+	unsigned long next;
+	int err = 0;
+
+	pgd = pgd_offset(walk->mm, addr);
+	do {
+		next = pgd_addr_end(addr, end);
+		if (pgd_none_or_clear_bad(pgd)) {
+			if (walk->pte_hole)
+				err = walk->pte_hole(addr, next, walk);
+			if (err)
+				break;
+			continue;
+		}
+		if (walk->pmd_entry || walk->pte_entry)
+			err = walk_pud_range(pgd, addr, next, walk);
+		if (err)
+			break;
+	} while (pgd++, addr = next, addr != end);
+
+	return err;
+}
+
 #ifdef CONFIG_HUGETLB_PAGE
 static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
 				       unsigned long end)
@@ -103,10 +129,10 @@ static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
 	return boundary < end ? boundary : end;
 }
 
-static int walk_hugetlb_range(struct vm_area_struct *vma,
-			      unsigned long addr, unsigned long end,
+static int walk_hugetlb_range(unsigned long addr, unsigned long end,
 			      struct mm_walk *walk)
 {
+	struct vm_area_struct *vma = walk->vma;
 	struct hstate *h = hstate_vma(vma);
 	unsigned long next;
 	unsigned long hmask = huge_page_mask(h);
@@ -119,15 +145,14 @@ static int walk_hugetlb_range(struct vm_area_struct *vma,
 		if (pte && walk->hugetlb_entry)
 			err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
 		if (err)
-			return err;
+			break;
 	} while (addr = next, addr != end);
 
-	return 0;
+	return err;
 }
 
 #else /* CONFIG_HUGETLB_PAGE */
-static int walk_hugetlb_range(struct vm_area_struct *vma,
-			      unsigned long addr, unsigned long end,
+static int walk_hugetlb_range(unsigned long addr, unsigned long end,
 			      struct mm_walk *walk)
 {
 	return 0;
@@ -135,109 +160,115 @@ static int walk_hugetlb_range(struct vm_area_struct *vma,
 
 #endif /* CONFIG_HUGETLB_PAGE */
 
+/*
+ * Decide whether we really walk over the current vma on [@start, @end)
+ * or skip it via the returned value. Return 0 if we do walk over the
+ * current vma, and return 1 if we skip the vma. Negative values means
+ * error, where we abort the current walk.
+ *
+ * Default check (only VM_PFNMAP check for now) is used when the caller
+ * doesn't define test_walk() callback.
+ */
+static int walk_page_test(unsigned long start, unsigned long end,
+			struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
 
+	if (walk->test_walk)
+		return walk->test_walk(start, end, walk);
+
+	/*
+	 * Do not walk over vma(VM_PFNMAP), because we have no valid struct
+	 * page backing a VM_PFNMAP range. See also commit a9ff785e4437.
+	 */
+	if (vma->vm_flags & VM_PFNMAP)
+		return 1;
+	return 0;
+}
+
+static int __walk_page_range(unsigned long start, unsigned long end,
+			struct mm_walk *walk)
+{
+	int err = 0;
+	struct vm_area_struct *vma = walk->vma;
+
+	if (vma && is_vm_hugetlb_page(vma)) {
+		if (walk->hugetlb_entry)
+			err = walk_hugetlb_range(start, end, walk);
+	} else
+		err = walk_pgd_range(start, end, walk);
+
+	return err;
+}
 
 /**
- * walk_page_range - walk a memory map's page tables with a callback
- * @addr: starting address
- * @end: ending address
- * @walk: set of callbacks to invoke for each level of the tree
- *
- * Recursively walk the page table for the memory area in a VMA,
- * calling supplied callbacks. Callbacks are called in-order (first
- * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
- * etc.). If lower-level callbacks are omitted, walking depth is reduced.
+ * walk_page_range - walk page table with caller specific callbacks
  *
- * Each callback receives an entry pointer and the start and end of the
- * associated range, and a copy of the original mm_walk for access to
- * the ->private or ->mm fields.
+ * Recursively walk the page table tree of the process represented by @walk->mm
+ * within the virtual address range [@start, @end). During walking, we can do
+ * some caller-specific works for each entry, by setting up pmd_entry(),
+ * pte_entry(), and/or hugetlb_entry(). If you don't set up for some of these
+ * callbacks, the associated entries/pages are just ignored.
+ * The return values of these callbacks are commonly defined like below:
+ *  - 0  : succeeded to handle the current entry, and if you don't reach the
+ *         end address yet, continue to walk.
+ *  - >0 : succeeded to handle the current entry, and return to the caller
+ *         with caller specific value.
+ *  - <0 : failed to handle the current entry, and return to the caller
+ *         with error code.
  *
- * Usually no locks are taken, but splitting transparent huge page may
- * take page table lock. And the bottom level iterator will map PTE
- * directories from highmem if necessary.
+ * Before starting to walk page table, some callers want to check whether
+ * they really want to walk over the current vma, typically by checking
+ * its vm_flags. walk_page_test() and @walk->test_walk() are used for this
+ * purpose.
  *
- * If any callback returns a non-zero value, the walk is aborted and
- * the return value is propagated back to the caller. Otherwise 0 is returned.
+ * struct mm_walk keeps current values of some common data like vma and pmd,
+ * which are useful for the access from callbacks. If you want to pass some
+ * caller-specific data to callbacks, @walk->private should be helpful.
  *
- * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry
- * is !NULL.
+ * Locking:
+ *   Callers of walk_page_range() and walk_page_vma() should hold
+ *   @walk->mm->mmap_sem, because these function traverse vma list and/or
+ *   access to vma's data.
  */
-int walk_page_range(unsigned long addr, unsigned long end,
+int walk_page_range(unsigned long start, unsigned long end,
 		    struct mm_walk *walk)
 {
-	pgd_t *pgd;
-	unsigned long next;
 	int err = 0;
+	unsigned long next;
+	struct vm_area_struct *vma;
 
-	if (addr >= end)
-		return err;
+	if (start >= end)
+		return -EINVAL;
 
 	if (!walk->mm)
 		return -EINVAL;
 
 	VM_BUG_ON_MM(!rwsem_is_locked(&walk->mm->mmap_sem), walk->mm);
 
-	pgd = pgd_offset(walk->mm, addr);
+	vma = find_vma(walk->mm, start);
 	do {
-		struct vm_area_struct *vma = NULL;
+		if (!vma) { /* after the last vma */
+			walk->vma = NULL;
+			next = end;
+		} else if (start < vma->vm_start) { /* outside vma */
+			walk->vma = NULL;
+			next = min(end, vma->vm_start);
+		} else { /* inside vma */
+			walk->vma = vma;
+			next = min(end, vma->vm_end);
+			vma = vma->vm_next;
 
-		next = pgd_addr_end(addr, end);
-
-		/*
-		 * This function was not intended to be vma based.
-		 * But there are vma special cases to be handled:
-		 * - hugetlb vma's
-		 * - VM_PFNMAP vma's
-		 */
-		vma = find_vma(walk->mm, addr);
-		if (vma) {
-			/*
-			 * There are no page structures backing a VM_PFNMAP
-			 * range, so do not allow split_huge_page_pmd().
-			 */
-			if ((vma->vm_start <= addr) &&
-			    (vma->vm_flags & VM_PFNMAP)) {
-				next = vma->vm_end;
-				pgd = pgd_offset(walk->mm, next);
+			err = walk_page_test(start, next, walk);
+			if (err > 0)
 				continue;
-			}
-			/*
-			 * Handle hugetlb vma individually because pagetable
-			 * walk for the hugetlb page is dependent on the
-			 * architecture and we can't handled it in the same
-			 * manner as non-huge pages.
-			 */
-			if (walk->hugetlb_entry && (vma->vm_start <= addr) &&
-			    is_vm_hugetlb_page(vma)) {
-				if (vma->vm_end < next)
-					next = vma->vm_end;
-				/*
-				 * Hugepage is very tightly coupled with vma,
-				 * so walk through hugetlb entries within a
-				 * given vma.
-				 */
-				err = walk_hugetlb_range(vma, addr, next, walk);
-				if (err)
-					break;
-				pgd = pgd_offset(walk->mm, next);
-				continue;
-			}
-		}
-
-		if (pgd_none_or_clear_bad(pgd)) {
-			if (walk->pte_hole)
-				err = walk->pte_hole(addr, next, walk);
-			if (err)
+			if (err < 0)
 				break;
-			pgd++;
-			continue;
 		}
-		if (walk->pmd_entry || walk->pte_entry)
-			err = walk_pud_range(pgd, addr, next, walk);
+		if (walk->vma || walk->pte_hole)
+			err = __walk_page_range(start, next, walk);
 		if (err)
 			break;
-		pgd++;
-	} while (addr = next, addr < end);
-
+	} while (start = next, start < end);
 	return err;
 }
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 03/13] pagewalk: add walk_page_vma()

[Naoya Horiguchi]

Introduces walk_page_vma(), which is useful for the callers which want to
walk over a given vma.  It's used by later patches.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
ChangeLog v3:
- check walk_page_test's return value instead of walk->skip
---
 include/linux/mm.h |  1 +
 mm/pagewalk.c      | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git mmotm-2014-11-05-16-01.orig/include/linux/mm.h mmotm-2014-11-05-16-01/include/linux/mm.h
index 25a4cf75b575..1022cc27150e 100644
--- mmotm-2014-11-05-16-01.orig/include/linux/mm.h
+++ mmotm-2014-11-05-16-01/include/linux/mm.h
@@ -1157,6 +1157,7 @@ struct mm_walk {
 
 int walk_page_range(unsigned long addr, unsigned long end,
 		struct mm_walk *walk);
+int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 		unsigned long end, unsigned long floor, unsigned long ceiling);
 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
diff --git mmotm-2014-11-05-16-01.orig/mm/pagewalk.c mmotm-2014-11-05-16-01/mm/pagewalk.c
index d9cc3caae802..4c9a653ba563 100644
--- mmotm-2014-11-05-16-01.orig/mm/pagewalk.c
+++ mmotm-2014-11-05-16-01/mm/pagewalk.c
@@ -272,3 +272,21 @@ int walk_page_range(unsigned long start, unsigned long end,
 	} while (start = next, start < end);
 	return err;
 }
+
+int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk)
+{
+	int err;
+
+	if (!walk->mm)
+		return -EINVAL;
+
+	VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem));
+	VM_BUG_ON(!vma);
+	walk->vma = vma;
+	err = walk_page_test(vma->vm_start, vma->vm_end, walk);
+	if (err > 0)
+		return 0;
+	if (err < 0)
+		return err;
+	return __walk_page_range(vma->vm_start, vma->vm_end, walk);
+}
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 04/13] smaps: remove mem_size_stats->vma and use walk_page_vma()

[Naoya Horiguchi]

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private. And show_smap() walks pages on vma basis, so using
walk_page_vma() is preferable.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 fs/proc/task_mmu.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index 2ab200d429be..c1b937095625 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -433,7 +433,6 @@ const struct file_operations proc_tid_maps_operations = {
 
 #ifdef CONFIG_PROC_PAGE_MONITOR
 struct mem_size_stats {
-	struct vm_area_struct *vma;
 	unsigned long resident;
 	unsigned long shared_clean;
 	unsigned long shared_dirty;
@@ -480,7 +479,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 		struct mm_walk *walk)
 {
 	struct mem_size_stats *mss = walk->private;
-	struct vm_area_struct *vma = mss->vma;
+	struct vm_area_struct *vma = walk->vma;
 	pgoff_t pgoff = linear_page_index(vma, addr);
 	struct page *page = NULL;
 
@@ -512,7 +511,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 		struct mm_walk *walk)
 {
 	struct mem_size_stats *mss = walk->private;
-	struct vm_area_struct *vma = mss->vma;
+	struct vm_area_struct *vma = walk->vma;
 	struct page *page;
 
 	/* FOLL_DUMP will return -EFAULT on huge zero page */
@@ -533,8 +532,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			   struct mm_walk *walk)
 {
-	struct mem_size_stats *mss = walk->private;
-	struct vm_area_struct *vma = mss->vma;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte;
 	spinlock_t *ptl;
 
@@ -624,10 +622,8 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 	};
 
 	memset(&mss, 0, sizeof mss);
-	mss.vma = vma;
 	/* mmap_sem is held in m_start */
-	if (vma->vm_mm && !is_vm_hugetlb_page(vma))
-		walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
+	walk_page_vma(vma, &smaps_walk);
 
 	show_map_vma(m, vma, is_pid);
 
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 03/13] pagewalk: add walk_page_vma()

[Naoya Horiguchi]

Introduces walk_page_vma(), which is useful for the callers which want to
walk over a given vma.  It's used by later patches.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
ChangeLog v3:
- check walk_page_test's return value instead of walk->skip
---
 include/linux/mm.h |  1 +
 mm/pagewalk.c      | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git mmotm-2014-11-05-16-01.orig/include/linux/mm.h mmotm-2014-11-05-16-01/include/linux/mm.h
index 25a4cf75b575..1022cc27150e 100644
--- mmotm-2014-11-05-16-01.orig/include/linux/mm.h
+++ mmotm-2014-11-05-16-01/include/linux/mm.h
@@ -1157,6 +1157,7 @@ struct mm_walk {
 
 int walk_page_range(unsigned long addr, unsigned long end,
 		struct mm_walk *walk);
+int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk);
 void free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
 		unsigned long end, unsigned long floor, unsigned long ceiling);
 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
diff --git mmotm-2014-11-05-16-01.orig/mm/pagewalk.c mmotm-2014-11-05-16-01/mm/pagewalk.c
index d9cc3caae802..4c9a653ba563 100644
--- mmotm-2014-11-05-16-01.orig/mm/pagewalk.c
+++ mmotm-2014-11-05-16-01/mm/pagewalk.c
@@ -272,3 +272,21 @@ int walk_page_range(unsigned long start, unsigned long end,
 	} while (start = next, start < end);
 	return err;
 }
+
+int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk)
+{
+	int err;
+
+	if (!walk->mm)
+		return -EINVAL;
+
+	VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem));
+	VM_BUG_ON(!vma);
+	walk->vma = vma;
+	err = walk_page_test(vma->vm_start, vma->vm_end, walk);
+	if (err > 0)
+		return 0;
+	if (err < 0)
+		return err;
+	return __walk_page_range(vma->vm_start, vma->vm_end, walk);
+}
-- 
2.2.0.rc0.2.gf745acb

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
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[PATCH -mm v7 04/13] smaps: remove mem_size_stats->vma and use walk_page_vma()

[Naoya Horiguchi]

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private. And show_smap() walks pages on vma basis, so using
walk_page_vma() is preferable.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 fs/proc/task_mmu.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index 2ab200d429be..c1b937095625 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -433,7 +433,6 @@ const struct file_operations proc_tid_maps_operations = {
 
 #ifdef CONFIG_PROC_PAGE_MONITOR
 struct mem_size_stats {
-	struct vm_area_struct *vma;
 	unsigned long resident;
 	unsigned long shared_clean;
 	unsigned long shared_dirty;
@@ -480,7 +479,7 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr,
 		struct mm_walk *walk)
 {
 	struct mem_size_stats *mss = walk->private;
-	struct vm_area_struct *vma = mss->vma;
+	struct vm_area_struct *vma = walk->vma;
 	pgoff_t pgoff = linear_page_index(vma, addr);
 	struct page *page = NULL;
 
@@ -512,7 +511,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 		struct mm_walk *walk)
 {
 	struct mem_size_stats *mss = walk->private;
-	struct vm_area_struct *vma = mss->vma;
+	struct vm_area_struct *vma = walk->vma;
 	struct page *page;
 
 	/* FOLL_DUMP will return -EFAULT on huge zero page */
@@ -533,8 +532,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			   struct mm_walk *walk)
 {
-	struct mem_size_stats *mss = walk->private;
-	struct vm_area_struct *vma = mss->vma;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte;
 	spinlock_t *ptl;
 
@@ -624,10 +622,8 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 	};
 
 	memset(&mss, 0, sizeof mss);
-	mss.vma = vma;
 	/* mmap_sem is held in m_start */
-	if (vma->vm_mm && !is_vm_hugetlb_page(vma))
-		walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
+	walk_page_vma(vma, &smaps_walk);
 
 	show_map_vma(m, vma, is_pid);
 
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 05/13] clear_refs: remove clear_refs_private->vma and introduce clear_refs_test_walk()

[Naoya Horiguchi]

clear_refs_write() has some prechecks to determine if we really walk over
a given vma. Now we have a test_walk() callback to filter vmas, so let's
utilize it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
ChangeLog v5:
- remove unused vma

ChangeLog v4:
- use walk_page_range instead of walk_page_vma with for loop
---
 fs/proc/task_mmu.c | 46 ++++++++++++++++++++++------------------------
 1 file changed, 22 insertions(+), 24 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index c1b937095625..9aaab24677ae 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -741,7 +741,6 @@ enum clear_refs_types {
 };
 
 struct clear_refs_private {
-	struct vm_area_struct *vma;
 	enum clear_refs_types type;
 };
 
@@ -774,7 +773,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 				unsigned long end, struct mm_walk *walk)
 {
 	struct clear_refs_private *cp = walk->private;
-	struct vm_area_struct *vma = cp->vma;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte, ptent;
 	spinlock_t *ptl;
 	struct page *page;
@@ -808,6 +807,25 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 
+static int clear_refs_test_walk(unsigned long start, unsigned long end,
+				struct mm_walk *walk)
+{
+	struct clear_refs_private *cp = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+
+	/*
+	 * Writing 1 to /proc/pid/clear_refs affects all pages.
+	 * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
+	 * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
+	 * Writing 4 to /proc/pid/clear_refs affects all pages.
+	 */
+	if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
+		return 1;
+	if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
+		return 1;
+	return 0;
+}
+
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
@@ -848,6 +866,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 		};
 		struct mm_walk clear_refs_walk = {
 			.pmd_entry = clear_refs_pte_range,
+			.test_walk = clear_refs_test_walk,
 			.mm = mm,
 			.private = &cp,
 		};
@@ -867,28 +886,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 			}
 			mmu_notifier_invalidate_range_start(mm, 0, -1);
 		}
-		for (vma = mm->mmap; vma; vma = vma->vm_next) {
-			cp.vma = vma;
-			if (is_vm_hugetlb_page(vma))
-				continue;
-			/*
-			 * Writing 1 to /proc/pid/clear_refs affects all pages.
-			 *
-			 * Writing 2 to /proc/pid/clear_refs only affects
-			 * Anonymous pages.
-			 *
-			 * Writing 3 to /proc/pid/clear_refs only affects file
-			 * mapped pages.
-			 *
-			 * Writing 4 to /proc/pid/clear_refs affects all pages.
-			 */
-			if (type == CLEAR_REFS_ANON && vma->vm_file)
-				continue;
-			if (type == CLEAR_REFS_MAPPED && !vma->vm_file)
-				continue;
-			walk_page_range(vma->vm_start, vma->vm_end,
-					&clear_refs_walk);
-		}
+		walk_page_range(0, ~0UL, &clear_refs_walk);
 		if (type == CLEAR_REFS_SOFT_DIRTY)
 			mmu_notifier_invalidate_range_end(mm, 0, -1);
 		flush_tlb_mm(mm);
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 05/13] clear_refs: remove clear_refs_private->vma and introduce clear_refs_test_walk()

[Naoya Horiguchi]

clear_refs_write() has some prechecks to determine if we really walk over
a given vma. Now we have a test_walk() callback to filter vmas, so let's
utilize it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
ChangeLog v5:
- remove unused vma

ChangeLog v4:
- use walk_page_range instead of walk_page_vma with for loop
---
 fs/proc/task_mmu.c | 46 ++++++++++++++++++++++------------------------
 1 file changed, 22 insertions(+), 24 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index c1b937095625..9aaab24677ae 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -741,7 +741,6 @@ enum clear_refs_types {
 };
 
 struct clear_refs_private {
-	struct vm_area_struct *vma;
 	enum clear_refs_types type;
 };
 
@@ -774,7 +773,7 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 				unsigned long end, struct mm_walk *walk)
 {
 	struct clear_refs_private *cp = walk->private;
-	struct vm_area_struct *vma = cp->vma;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte, ptent;
 	spinlock_t *ptl;
 	struct page *page;
@@ -808,6 +807,25 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 
+static int clear_refs_test_walk(unsigned long start, unsigned long end,
+				struct mm_walk *walk)
+{
+	struct clear_refs_private *cp = walk->private;
+	struct vm_area_struct *vma = walk->vma;
+
+	/*
+	 * Writing 1 to /proc/pid/clear_refs affects all pages.
+	 * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
+	 * Writing 3 to /proc/pid/clear_refs only affects file mapped pages.
+	 * Writing 4 to /proc/pid/clear_refs affects all pages.
+	 */
+	if (cp->type == CLEAR_REFS_ANON && vma->vm_file)
+		return 1;
+	if (cp->type == CLEAR_REFS_MAPPED && !vma->vm_file)
+		return 1;
+	return 0;
+}
+
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
@@ -848,6 +866,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 		};
 		struct mm_walk clear_refs_walk = {
 			.pmd_entry = clear_refs_pte_range,
+			.test_walk = clear_refs_test_walk,
 			.mm = mm,
 			.private = &cp,
 		};
@@ -867,28 +886,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 			}
 			mmu_notifier_invalidate_range_start(mm, 0, -1);
 		}
-		for (vma = mm->mmap; vma; vma = vma->vm_next) {
-			cp.vma = vma;
-			if (is_vm_hugetlb_page(vma))
-				continue;
-			/*
-			 * Writing 1 to /proc/pid/clear_refs affects all pages.
-			 *
-			 * Writing 2 to /proc/pid/clear_refs only affects
-			 * Anonymous pages.
-			 *
-			 * Writing 3 to /proc/pid/clear_refs only affects file
-			 * mapped pages.
-			 *
-			 * Writing 4 to /proc/pid/clear_refs affects all pages.
-			 */
-			if (type == CLEAR_REFS_ANON && vma->vm_file)
-				continue;
-			if (type == CLEAR_REFS_MAPPED && !vma->vm_file)
-				continue;
-			walk_page_range(vma->vm_start, vma->vm_end,
-					&clear_refs_walk);
-		}
+		walk_page_range(0, ~0UL, &clear_refs_walk);
 		if (type == CLEAR_REFS_SOFT_DIRTY)
 			mmu_notifier_invalidate_range_end(mm, 0, -1);
 		flush_tlb_mm(mm);
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 06/13] pagemap: use walk->vma instead of calling find_vma()

[Naoya Horiguchi]

Page table walker has the information of the current vma in mm_walk,
so we don't have to call find_vma() in each pagemap_(pte|hugetlb)_range()
call any longer. Currently pagemap_pte_range() does vma loop itself, so
this patch reduces many lines of code.

NULL-vma check is omitted because we assume that we never run these
callbacks on any address outside vma. And even if it were broken, NULL
pointer dereference would be detected, so we can get enough information
for debugging.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v7:
- remove while-loop in pagemap_pte_range() (thanks to Peter Feiner)
- remove Kirill's Ack because this patch has non-minor change since v6
---
 fs/proc/task_mmu.c | 68 +++++++++++++-----------------------------------------
 1 file changed, 16 insertions(+), 52 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index 9aaab24677ae..f997734d2b4b 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -1054,15 +1054,13 @@ static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemap
 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			     struct mm_walk *walk)
 {
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma = walk->vma;
 	struct pagemapread *pm = walk->private;
 	spinlock_t *ptl;
 	pte_t *pte;
 	int err = 0;
 
-	/* find the first VMA at or above 'addr' */
-	vma = find_vma(walk->mm, addr);
-	if (vma && pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
 		int pmd_flags2;
 
 		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
@@ -1088,50 +1086,19 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	if (pmd_trans_unstable(pmd))
 		return 0;
 
-	while (1) {
-		/* End of address space hole, which we mark as non-present. */
-		unsigned long hole_end;
-
-		if (vma)
-			hole_end = min(end, vma->vm_start);
-		else
-			hole_end = end;
-
-		for (; addr < hole_end; addr += PAGE_SIZE) {
-			pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
-
-			err = add_to_pagemap(addr, &pme, pm);
-			if (err)
-				return err;
-		}
-
-		if (!vma || vma->vm_start >= end)
-			break;
-		/*
-		 * We can't possibly be in a hugetlb VMA. In general,
-		 * for a mm_walk with a pmd_entry and a hugetlb_entry,
-		 * the pmd_entry can only be called on addresses in a
-		 * hugetlb if the walk starts in a non-hugetlb VMA and
-		 * spans a hugepage VMA. Since pagemap_read walks are
-		 * PMD-sized and PMD-aligned, this will never be true.
-		 */
-		BUG_ON(is_vm_hugetlb_page(vma));
-
-		/* Addresses in the VMA. */
-		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
-			pagemap_entry_t pme;
-			pte = pte_offset_map(pmd, addr);
-			pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
-			pte_unmap(pte);
-			err = add_to_pagemap(addr, &pme, pm);
-			if (err)
-				return err;
-		}
-
-		if (addr == end)
-			break;
+	/*
+	 * We can assume that @vma always points to a valid one and @end never
+	 * goes beyond vma->vm_end.
+	 */
+	for (; addr < end; addr += PAGE_SIZE) {
+		pagemap_entry_t pme;
 
-		vma = find_vma(walk->mm, addr);
+		pte = pte_offset_map(pmd, addr);
+		pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
+		pte_unmap(pte);
+		err = add_to_pagemap(addr, &pme, pm);
+		if (err)
+			return err;
 	}
 
 	cond_resched();
@@ -1158,15 +1125,12 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
 				 struct mm_walk *walk)
 {
 	struct pagemapread *pm = walk->private;
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma = walk->vma;
 	int err = 0;
 	int flags2;
 	pagemap_entry_t pme;
 
-	vma = find_vma(walk->mm, addr);
-	WARN_ON_ONCE(!vma);
-
-	if (vma && (vma->vm_flags & VM_SOFTDIRTY))
+	if (vma->vm_flags & VM_SOFTDIRTY)
 		flags2 = __PM_SOFT_DIRTY;
 	else
 		flags2 = 0;
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 06/13] pagemap: use walk->vma instead of calling find_vma()

[Naoya Horiguchi]

Page table walker has the information of the current vma in mm_walk,
so we don't have to call find_vma() in each pagemap_(pte|hugetlb)_range()
call any longer. Currently pagemap_pte_range() does vma loop itself, so
this patch reduces many lines of code.

NULL-vma check is omitted because we assume that we never run these
callbacks on any address outside vma. And even if it were broken, NULL
pointer dereference would be detected, so we can get enough information
for debugging.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v7:
- remove while-loop in pagemap_pte_range() (thanks to Peter Feiner)
- remove Kirill's Ack because this patch has non-minor change since v6
---
 fs/proc/task_mmu.c | 68 +++++++++++++-----------------------------------------
 1 file changed, 16 insertions(+), 52 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index 9aaab24677ae..f997734d2b4b 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -1054,15 +1054,13 @@ static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemap
 static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 			     struct mm_walk *walk)
 {
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma = walk->vma;
 	struct pagemapread *pm = walk->private;
 	spinlock_t *ptl;
 	pte_t *pte;
 	int err = 0;
 
-	/* find the first VMA at or above 'addr' */
-	vma = find_vma(walk->mm, addr);
-	if (vma && pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
 		int pmd_flags2;
 
 		if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
@@ -1088,50 +1086,19 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	if (pmd_trans_unstable(pmd))
 		return 0;
 
-	while (1) {
-		/* End of address space hole, which we mark as non-present. */
-		unsigned long hole_end;
-
-		if (vma)
-			hole_end = min(end, vma->vm_start);
-		else
-			hole_end = end;
-
-		for (; addr < hole_end; addr += PAGE_SIZE) {
-			pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
-
-			err = add_to_pagemap(addr, &pme, pm);
-			if (err)
-				return err;
-		}
-
-		if (!vma || vma->vm_start >= end)
-			break;
-		/*
-		 * We can't possibly be in a hugetlb VMA. In general,
-		 * for a mm_walk with a pmd_entry and a hugetlb_entry,
-		 * the pmd_entry can only be called on addresses in a
-		 * hugetlb if the walk starts in a non-hugetlb VMA and
-		 * spans a hugepage VMA. Since pagemap_read walks are
-		 * PMD-sized and PMD-aligned, this will never be true.
-		 */
-		BUG_ON(is_vm_hugetlb_page(vma));
-
-		/* Addresses in the VMA. */
-		for (; addr < min(end, vma->vm_end); addr += PAGE_SIZE) {
-			pagemap_entry_t pme;
-			pte = pte_offset_map(pmd, addr);
-			pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
-			pte_unmap(pte);
-			err = add_to_pagemap(addr, &pme, pm);
-			if (err)
-				return err;
-		}
-
-		if (addr == end)
-			break;
+	/*
+	 * We can assume that @vma always points to a valid one and @end never
+	 * goes beyond vma->vm_end.
+	 */
+	for (; addr < end; addr += PAGE_SIZE) {
+		pagemap_entry_t pme;
 
-		vma = find_vma(walk->mm, addr);
+		pte = pte_offset_map(pmd, addr);
+		pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
+		pte_unmap(pte);
+		err = add_to_pagemap(addr, &pme, pm);
+		if (err)
+			return err;
 	}
 
 	cond_resched();
@@ -1158,15 +1125,12 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask,
 				 struct mm_walk *walk)
 {
 	struct pagemapread *pm = walk->private;
-	struct vm_area_struct *vma;
+	struct vm_area_struct *vma = walk->vma;
 	int err = 0;
 	int flags2;
 	pagemap_entry_t pme;
 
-	vma = find_vma(walk->mm, addr);
-	WARN_ON_ONCE(!vma);
-
-	if (vma && (vma->vm_flags & VM_SOFTDIRTY))
+	if (vma->vm_flags & VM_SOFTDIRTY)
 		flags2 = __PM_SOFT_DIRTY;
 	else
 		flags2 = 0;
-- 
2.2.0.rc0.2.gf745acb

--
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[PATCH -mm v7 07/13] numa_maps: fix typo in gather_hugetbl_stats

[Naoya Horiguchi]

Just doing s/gather_hugetbl_stats/gather_hugetlb_stats/g, this makes code
grep-friendly.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 fs/proc/task_mmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index f997734d2b4b..bddae83fbf39 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -1392,7 +1392,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 #ifdef CONFIG_HUGETLB_PAGE
-static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
+static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 		unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
 	struct numa_maps *md;
@@ -1411,7 +1411,7 @@ static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
 }
 
 #else
-static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
+static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 		unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
 	return 0;
@@ -1442,7 +1442,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 
 	md->vma = vma;
 
-	walk.hugetlb_entry = gather_hugetbl_stats;
+	walk.hugetlb_entry = gather_hugetlb_stats;
 	walk.pmd_entry = gather_pte_stats;
 	walk.private = md;
 	walk.mm = mm;
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 07/13] numa_maps: fix typo in gather_hugetbl_stats

[Naoya Horiguchi]

Just doing s/gather_hugetbl_stats/gather_hugetlb_stats/g, this makes code
grep-friendly.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 fs/proc/task_mmu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index f997734d2b4b..bddae83fbf39 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -1392,7 +1392,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 	return 0;
 }
 #ifdef CONFIG_HUGETLB_PAGE
-static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
+static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 		unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
 	struct numa_maps *md;
@@ -1411,7 +1411,7 @@ static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
 }
 
 #else
-static int gather_hugetbl_stats(pte_t *pte, unsigned long hmask,
+static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 		unsigned long addr, unsigned long end, struct mm_walk *walk)
 {
 	return 0;
@@ -1442,7 +1442,7 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 
 	md->vma = vma;
 
-	walk.hugetlb_entry = gather_hugetbl_stats;
+	walk.hugetlb_entry = gather_hugetlb_stats;
 	walk.pmd_entry = gather_pte_stats;
 	walk.private = md;
 	walk.mm = mm;
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 08/13] numa_maps: remove numa_maps->vma

[Naoya Horiguchi]

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private. And show_numa_map() walks pages on vma basis, so using
walk_page_vma() is preferable.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 fs/proc/task_mmu.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index bddae83fbf39..e7d86b97598b 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -1290,7 +1290,6 @@ const struct file_operations proc_pagemap_operations = {
 #ifdef CONFIG_NUMA
 
 struct numa_maps {
-	struct vm_area_struct *vma;
 	unsigned long pages;
 	unsigned long anon;
 	unsigned long active;
@@ -1359,18 +1358,17 @@ static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 		unsigned long end, struct mm_walk *walk)
 {
-	struct numa_maps *md;
+	struct numa_maps *md = walk->private;
+	struct vm_area_struct *vma = walk->vma;
 	spinlock_t *ptl;
 	pte_t *orig_pte;
 	pte_t *pte;
 
-	md = walk->private;
-
-	if (pmd_trans_huge_lock(pmd, md->vma, &ptl) == 1) {
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
 		pte_t huge_pte = *(pte_t *)pmd;
 		struct page *page;
 
-		page = can_gather_numa_stats(huge_pte, md->vma, addr);
+		page = can_gather_numa_stats(huge_pte, vma, addr);
 		if (page)
 			gather_stats(page, md, pte_dirty(huge_pte),
 				     HPAGE_PMD_SIZE/PAGE_SIZE);
@@ -1382,7 +1380,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 		return 0;
 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
 	do {
-		struct page *page = can_gather_numa_stats(*pte, md->vma, addr);
+		struct page *page = can_gather_numa_stats(*pte, vma, addr);
 		if (!page)
 			continue;
 		gather_stats(page, md, pte_dirty(*pte), 1);
@@ -1429,7 +1427,12 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 	struct numa_maps *md = &numa_priv->md;
 	struct file *file = vma->vm_file;
 	struct mm_struct *mm = vma->vm_mm;
-	struct mm_walk walk = {};
+	struct mm_walk walk = {
+		.hugetlb_entry = gather_hugetlb_stats,
+		.pmd_entry = gather_pte_stats,
+		.private = md,
+		.mm = mm,
+	};
 	struct mempolicy *pol;
 	char buffer[64];
 	int nid;
@@ -1440,13 +1443,6 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 	/* Ensure we start with an empty set of numa_maps statistics. */
 	memset(md, 0, sizeof(*md));
 
-	md->vma = vma;
-
-	walk.hugetlb_entry = gather_hugetlb_stats;
-	walk.pmd_entry = gather_pte_stats;
-	walk.private = md;
-	walk.mm = mm;
-
 	pol = __get_vma_policy(vma, vma->vm_start);
 	if (pol) {
 		mpol_to_str(buffer, sizeof(buffer), pol);
@@ -1480,7 +1476,8 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 	if (is_vm_hugetlb_page(vma))
 		seq_puts(m, " huge");
 
-	walk_page_range(vma->vm_start, vma->vm_end, &walk);
+	/* mmap_sem is held by m_start */
+	walk_page_vma(vma, &walk);
 
 	if (!md->pages)
 		goto out;
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 08/13] numa_maps: remove numa_maps->vma

[Naoya Horiguchi]

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private. And show_numa_map() walks pages on vma basis, so using
walk_page_vma() is preferable.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 fs/proc/task_mmu.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index bddae83fbf39..e7d86b97598b 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -1290,7 +1290,6 @@ const struct file_operations proc_pagemap_operations = {
 #ifdef CONFIG_NUMA
 
 struct numa_maps {
-	struct vm_area_struct *vma;
 	unsigned long pages;
 	unsigned long anon;
 	unsigned long active;
@@ -1359,18 +1358,17 @@ static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
 static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 		unsigned long end, struct mm_walk *walk)
 {
-	struct numa_maps *md;
+	struct numa_maps *md = walk->private;
+	struct vm_area_struct *vma = walk->vma;
 	spinlock_t *ptl;
 	pte_t *orig_pte;
 	pte_t *pte;
 
-	md = walk->private;
-
-	if (pmd_trans_huge_lock(pmd, md->vma, &ptl) == 1) {
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
 		pte_t huge_pte = *(pte_t *)pmd;
 		struct page *page;
 
-		page = can_gather_numa_stats(huge_pte, md->vma, addr);
+		page = can_gather_numa_stats(huge_pte, vma, addr);
 		if (page)
 			gather_stats(page, md, pte_dirty(huge_pte),
 				     HPAGE_PMD_SIZE/PAGE_SIZE);
@@ -1382,7 +1380,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
 		return 0;
 	orig_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
 	do {
-		struct page *page = can_gather_numa_stats(*pte, md->vma, addr);
+		struct page *page = can_gather_numa_stats(*pte, vma, addr);
 		if (!page)
 			continue;
 		gather_stats(page, md, pte_dirty(*pte), 1);
@@ -1429,7 +1427,12 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 	struct numa_maps *md = &numa_priv->md;
 	struct file *file = vma->vm_file;
 	struct mm_struct *mm = vma->vm_mm;
-	struct mm_walk walk = {};
+	struct mm_walk walk = {
+		.hugetlb_entry = gather_hugetlb_stats,
+		.pmd_entry = gather_pte_stats,
+		.private = md,
+		.mm = mm,
+	};
 	struct mempolicy *pol;
 	char buffer[64];
 	int nid;
@@ -1440,13 +1443,6 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 	/* Ensure we start with an empty set of numa_maps statistics. */
 	memset(md, 0, sizeof(*md));
 
-	md->vma = vma;
-
-	walk.hugetlb_entry = gather_hugetlb_stats;
-	walk.pmd_entry = gather_pte_stats;
-	walk.private = md;
-	walk.mm = mm;
-
 	pol = __get_vma_policy(vma, vma->vm_start);
 	if (pol) {
 		mpol_to_str(buffer, sizeof(buffer), pol);
@@ -1480,7 +1476,8 @@ static int show_numa_map(struct seq_file *m, void *v, int is_pid)
 	if (is_vm_hugetlb_page(vma))
 		seq_puts(m, " huge");
 
-	walk_page_range(vma->vm_start, vma->vm_end, &walk);
+	/* mmap_sem is held by m_start */
+	walk_page_vma(vma, &walk);
 
 	if (!md->pages)
 		goto out;
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 09/13] memcg: cleanup preparation for page table walk

[Naoya Horiguchi]

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private. And both of mem_cgroup_count_precharge() and
mem_cgroup_move_charge() do for each vma loop themselves, but now it's
done in pagewalk.c, so let's clean up them.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v4:
- use walk_page_range() instead of walk_page_vma() with for loop.
---
 mm/memcontrol.c | 49 ++++++++++++++++---------------------------------
 1 file changed, 16 insertions(+), 33 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/mm/memcontrol.c mmotm-2014-11-05-16-01/mm/memcontrol.c
index 496f0b9cd786..59d1342bbda7 100644
--- mmotm-2014-11-05-16-01.orig/mm/memcontrol.c
+++ mmotm-2014-11-05-16-01/mm/memcontrol.c
@@ -4959,7 +4959,7 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
 					unsigned long addr, unsigned long end,
 					struct mm_walk *walk)
 {
-	struct vm_area_struct *vma = walk->private;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte;
 	spinlock_t *ptl;
 
@@ -4985,20 +4985,13 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
 {
 	unsigned long precharge;
-	struct vm_area_struct *vma;
 
+	struct mm_walk mem_cgroup_count_precharge_walk = {
+		.pmd_entry = mem_cgroup_count_precharge_pte_range,
+		.mm = mm,
+	};
 	down_read(&mm->mmap_sem);
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		struct mm_walk mem_cgroup_count_precharge_walk = {
-			.pmd_entry = mem_cgroup_count_precharge_pte_range,
-			.mm = mm,
-			.private = vma,
-		};
-		if (is_vm_hugetlb_page(vma))
-			continue;
-		walk_page_range(vma->vm_start, vma->vm_end,
-					&mem_cgroup_count_precharge_walk);
-	}
+	walk_page_range(0, ~0UL, &mem_cgroup_count_precharge_walk);
 	up_read(&mm->mmap_sem);
 
 	precharge = mc.precharge;
@@ -5131,7 +5124,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
 				struct mm_walk *walk)
 {
 	int ret = 0;
-	struct vm_area_struct *vma = walk->private;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte;
 	spinlock_t *ptl;
 	enum mc_target_type target_type;
@@ -5227,7 +5220,10 @@ put:			/* get_mctgt_type() gets the page */
 
 static void mem_cgroup_move_charge(struct mm_struct *mm)
 {
-	struct vm_area_struct *vma;
+	struct mm_walk mem_cgroup_move_charge_walk = {
+		.pmd_entry = mem_cgroup_move_charge_pte_range,
+		.mm = mm,
+	};
 
 	lru_add_drain_all();
 	/*
@@ -5250,24 +5246,11 @@ static void mem_cgroup_move_charge(struct mm_struct *mm)
 		cond_resched();
 		goto retry;
 	}
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		int ret;
-		struct mm_walk mem_cgroup_move_charge_walk = {
-			.pmd_entry = mem_cgroup_move_charge_pte_range,
-			.mm = mm,
-			.private = vma,
-		};
-		if (is_vm_hugetlb_page(vma))
-			continue;
-		ret = walk_page_range(vma->vm_start, vma->vm_end,
-						&mem_cgroup_move_charge_walk);
-		if (ret)
-			/*
-			 * means we have consumed all precharges and failed in
-			 * doing additional charge. Just abandon here.
-			 */
-			break;
-	}
+	/*
+	 * When we have consumed all precharges and failed in doing
+	 * additional charge, the page walk just aborts.
+	 */
+	walk_page_range(0, ~0UL, &mem_cgroup_move_charge_walk);
 	up_read(&mm->mmap_sem);
 	atomic_dec(&mc.from->moving_account);
 }
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 09/13] memcg: cleanup preparation for page table walk

[Naoya Horiguchi]

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private. And both of mem_cgroup_count_precharge() and
mem_cgroup_move_charge() do for each vma loop themselves, but now it's
done in pagewalk.c, so let's clean up them.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v4:
- use walk_page_range() instead of walk_page_vma() with for loop.
---
 mm/memcontrol.c | 49 ++++++++++++++++---------------------------------
 1 file changed, 16 insertions(+), 33 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/mm/memcontrol.c mmotm-2014-11-05-16-01/mm/memcontrol.c
index 496f0b9cd786..59d1342bbda7 100644
--- mmotm-2014-11-05-16-01.orig/mm/memcontrol.c
+++ mmotm-2014-11-05-16-01/mm/memcontrol.c
@@ -4959,7 +4959,7 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
 					unsigned long addr, unsigned long end,
 					struct mm_walk *walk)
 {
-	struct vm_area_struct *vma = walk->private;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte;
 	spinlock_t *ptl;
 
@@ -4985,20 +4985,13 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
 {
 	unsigned long precharge;
-	struct vm_area_struct *vma;
 
+	struct mm_walk mem_cgroup_count_precharge_walk = {
+		.pmd_entry = mem_cgroup_count_precharge_pte_range,
+		.mm = mm,
+	};
 	down_read(&mm->mmap_sem);
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		struct mm_walk mem_cgroup_count_precharge_walk = {
-			.pmd_entry = mem_cgroup_count_precharge_pte_range,
-			.mm = mm,
-			.private = vma,
-		};
-		if (is_vm_hugetlb_page(vma))
-			continue;
-		walk_page_range(vma->vm_start, vma->vm_end,
-					&mem_cgroup_count_precharge_walk);
-	}
+	walk_page_range(0, ~0UL, &mem_cgroup_count_precharge_walk);
 	up_read(&mm->mmap_sem);
 
 	precharge = mc.precharge;
@@ -5131,7 +5124,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
 				struct mm_walk *walk)
 {
 	int ret = 0;
-	struct vm_area_struct *vma = walk->private;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *pte;
 	spinlock_t *ptl;
 	enum mc_target_type target_type;
@@ -5227,7 +5220,10 @@ put:			/* get_mctgt_type() gets the page */
 
 static void mem_cgroup_move_charge(struct mm_struct *mm)
 {
-	struct vm_area_struct *vma;
+	struct mm_walk mem_cgroup_move_charge_walk = {
+		.pmd_entry = mem_cgroup_move_charge_pte_range,
+		.mm = mm,
+	};
 
 	lru_add_drain_all();
 	/*
@@ -5250,24 +5246,11 @@ static void mem_cgroup_move_charge(struct mm_struct *mm)
 		cond_resched();
 		goto retry;
 	}
-	for (vma = mm->mmap; vma; vma = vma->vm_next) {
-		int ret;
-		struct mm_walk mem_cgroup_move_charge_walk = {
-			.pmd_entry = mem_cgroup_move_charge_pte_range,
-			.mm = mm,
-			.private = vma,
-		};
-		if (is_vm_hugetlb_page(vma))
-			continue;
-		ret = walk_page_range(vma->vm_start, vma->vm_end,
-						&mem_cgroup_move_charge_walk);
-		if (ret)
-			/*
-			 * means we have consumed all precharges and failed in
-			 * doing additional charge. Just abandon here.
-			 */
-			break;
-	}
+	/*
+	 * When we have consumed all precharges and failed in doing
+	 * additional charge, the page walk just aborts.
+	 */
+	walk_page_range(0, ~0UL, &mem_cgroup_move_charge_walk);
 	up_read(&mm->mmap_sem);
 	atomic_dec(&mc.from->moving_account);
 }
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 10/13] arch/powerpc/mm/subpage-prot.c: use walk->vma and walk_page_vma()

[Naoya Horiguchi]

We don't have to use mm_walk->private to pass vma to the callback function
because of mm_walk->vma. And walk_page_vma() is useful if we walk over a
single vma.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/powerpc/mm/subpage-prot.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/arch/powerpc/mm/subpage-prot.c mmotm-2014-11-05-16-01/arch/powerpc/mm/subpage-prot.c
index 6c0b1f5f8d2c..fa9fb5b4c66c 100644
--- mmotm-2014-11-05-16-01.orig/arch/powerpc/mm/subpage-prot.c
+++ mmotm-2014-11-05-16-01/arch/powerpc/mm/subpage-prot.c
@@ -134,7 +134,7 @@ static void subpage_prot_clear(unsigned long addr, unsigned long len)
 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->private;
+	struct vm_area_struct *vma = walk->vma;
 	split_huge_page_pmd(vma, addr, pmd);
 	return 0;
 }
@@ -163,9 +163,7 @@ static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 		if (vma->vm_start >= (addr + len))
 			break;
 		vma->vm_flags |= VM_NOHUGEPAGE;
-		subpage_proto_walk.private = vma;
-		walk_page_range(vma->vm_start, vma->vm_end,
-				&subpage_proto_walk);
+		walk_page_vma(vma, &subpage_proto_walk);
 		vma = vma->vm_next;
 	}
 }
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 10/13] arch/powerpc/mm/subpage-prot.c: use walk->vma and walk_page_vma()

[Naoya Horiguchi]

We don't have to use mm_walk->private to pass vma to the callback function
because of mm_walk->vma. And walk_page_vma() is useful if we walk over a
single vma.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 arch/powerpc/mm/subpage-prot.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/arch/powerpc/mm/subpage-prot.c mmotm-2014-11-05-16-01/arch/powerpc/mm/subpage-prot.c
index 6c0b1f5f8d2c..fa9fb5b4c66c 100644
--- mmotm-2014-11-05-16-01.orig/arch/powerpc/mm/subpage-prot.c
+++ mmotm-2014-11-05-16-01/arch/powerpc/mm/subpage-prot.c
@@ -134,7 +134,7 @@ static void subpage_prot_clear(unsigned long addr, unsigned long len)
 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->private;
+	struct vm_area_struct *vma = walk->vma;
 	split_huge_page_pmd(vma, addr, pmd);
 	return 0;
 }
@@ -163,9 +163,7 @@ static void subpage_mark_vma_nohuge(struct mm_struct *mm, unsigned long addr,
 		if (vma->vm_start >= (addr + len))
 			break;
 		vma->vm_flags |= VM_NOHUGEPAGE;
-		subpage_proto_walk.private = vma;
-		walk_page_range(vma->vm_start, vma->vm_end,
-				&subpage_proto_walk);
+		walk_page_vma(vma, &subpage_proto_walk);
 		vma = vma->vm_next;
 	}
 }
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 11/13] mempolicy: apply page table walker on queue_pages_range()

[Naoya Horiguchi]

queue_pages_range() does page table walking in its own way now, but there
is some code duplicate. This patch applies page table walker to reduce
lines of code.

queue_pages_range() has to do some precheck to determine whether we really
walk over the vma or just skip it. Now we have test_walk() callback in
mm_walk for this purpose, so we can do this replacement cleanly.
queue_pages_test_walk() depends on not only the current vma but also the
previous one, so queue_pages->prev is introduced to remember it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v4:
- rebase to v3.16-rc3, where the return value of queue_pages_range()
  becomes 0 in success instead of the first found vma, and use -EFAILT
  instead of ERR_PTR() in failure.
---
 mm/mempolicy.c | 228 +++++++++++++++++++++++----------------------------------
 1 file changed, 92 insertions(+), 136 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/mm/mempolicy.c mmotm-2014-11-05-16-01/mm/mempolicy.c
index e58725aff7e9..2c7c4e296386 100644
--- mmotm-2014-11-05-16-01.orig/mm/mempolicy.c
+++ mmotm-2014-11-05-16-01/mm/mempolicy.c
@@ -477,24 +477,34 @@ static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
 static void migrate_page_add(struct page *page, struct list_head *pagelist,
 				unsigned long flags);
 
+struct queue_pages {
+	struct list_head *pagelist;
+	unsigned long flags;
+	nodemask_t *nmask;
+	struct vm_area_struct *prev;
+};
+
 /*
  * Scan through pages checking if pages follow certain conditions,
  * and move them to the pagelist if they do.
  */
-static int queue_pages_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
+static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
+			unsigned long end, struct mm_walk *walk)
 {
-	pte_t *orig_pte;
+	struct vm_area_struct *vma = walk->vma;
+	struct page *page;
+	struct queue_pages *qp = walk->private;
+	unsigned long flags = qp->flags;
+	int nid;
 	pte_t *pte;
 	spinlock_t *ptl;
 
-	orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
-	do {
-		struct page *page;
-		int nid;
+	split_huge_page_pmd(vma, addr, pmd);
+	if (pmd_trans_unstable(pmd))
+		return 0;
 
+	pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+	for (; addr != end; pte++, addr += PAGE_SIZE) {
 		if (!pte_present(*pte))
 			continue;
 		page = vm_normal_page(vma, addr, *pte);
@@ -507,114 +517,46 @@ static int queue_pages_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 		if (PageReserved(page))
 			continue;
 		nid = page_to_nid(page);
-		if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
+		if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
 			continue;
 
 		if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
-			migrate_page_add(page, private, flags);
-		else
-			break;
-	} while (pte++, addr += PAGE_SIZE, addr != end);
-	pte_unmap_unlock(orig_pte, ptl);
-	return addr != end;
+			migrate_page_add(page, qp->pagelist, flags);
+	}
+	pte_unmap_unlock(pte - 1, ptl);
+	cond_resched();
+	return 0;
 }
 
-static void queue_pages_hugetlb_pmd_range(struct vm_area_struct *vma,
-		pmd_t *pmd, const nodemask_t *nodes, unsigned long flags,
-				    void *private)
+static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
+			       unsigned long addr, unsigned long end,
+			       struct mm_walk *walk)
 {
 #ifdef CONFIG_HUGETLB_PAGE
+	struct queue_pages *qp = walk->private;
+	unsigned long flags = qp->flags;
 	int nid;
 	struct page *page;
 	spinlock_t *ptl;
 	pte_t entry;
 
-	ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, (pte_t *)pmd);
-	entry = huge_ptep_get((pte_t *)pmd);
+	ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
+	entry = huge_ptep_get(pte);
 	if (!pte_present(entry))
 		goto unlock;
 	page = pte_page(entry);
 	nid = page_to_nid(page);
-	if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
+	if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
 		goto unlock;
 	/* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
 	if (flags & (MPOL_MF_MOVE_ALL) ||
 	    (flags & MPOL_MF_MOVE && page_mapcount(page) == 1))
-		isolate_huge_page(page, private);
+		isolate_huge_page(page, qp->pagelist);
 unlock:
 	spin_unlock(ptl);
 #else
 	BUG();
 #endif
-}
-
-static inline int queue_pages_pmd_range(struct vm_area_struct *vma, pud_t *pud,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
-{
-	pmd_t *pmd;
-	unsigned long next;
-
-	pmd = pmd_offset(pud, addr);
-	do {
-		next = pmd_addr_end(addr, end);
-		if (!pmd_present(*pmd))
-			continue;
-		if (pmd_huge(*pmd) && is_vm_hugetlb_page(vma)) {
-			queue_pages_hugetlb_pmd_range(vma, pmd, nodes,
-						flags, private);
-			continue;
-		}
-		split_huge_page_pmd(vma, addr, pmd);
-		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
-			continue;
-		if (queue_pages_pte_range(vma, pmd, addr, next, nodes,
-				    flags, private))
-			return -EIO;
-	} while (pmd++, addr = next, addr != end);
-	return 0;
-}
-
-static inline int queue_pages_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
-{
-	pud_t *pud;
-	unsigned long next;
-
-	pud = pud_offset(pgd, addr);
-	do {
-		next = pud_addr_end(addr, end);
-		if (pud_huge(*pud) && is_vm_hugetlb_page(vma))
-			continue;
-		if (pud_none_or_clear_bad(pud))
-			continue;
-		if (queue_pages_pmd_range(vma, pud, addr, next, nodes,
-				    flags, private))
-			return -EIO;
-	} while (pud++, addr = next, addr != end);
-	return 0;
-}
-
-static inline int queue_pages_pgd_range(struct vm_area_struct *vma,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
-{
-	pgd_t *pgd;
-	unsigned long next;
-
-	pgd = pgd_offset(vma->vm_mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(pgd))
-			continue;
-		if (queue_pages_pud_range(vma, pgd, addr, next, nodes,
-				    flags, private))
-			return -EIO;
-	} while (pgd++, addr = next, addr != end);
 	return 0;
 }
 
@@ -647,6 +589,46 @@ static unsigned long change_prot_numa(struct vm_area_struct *vma,
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
+static int queue_pages_test_walk(unsigned long start, unsigned long end,
+				struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
+	struct queue_pages *qp = walk->private;
+	unsigned long endvma = vma->vm_end;
+	unsigned long flags = qp->flags;
+
+	if (endvma > end)
+		endvma = end;
+	if (vma->vm_start > start)
+		start = vma->vm_start;
+
+	if (!(flags & MPOL_MF_DISCONTIG_OK)) {
+		if (!vma->vm_next && vma->vm_end < end)
+			return -EFAULT;
+		if (qp->prev && qp->prev->vm_end < vma->vm_start)
+			return -EFAULT;
+	}
+
+	qp->prev = vma;
+
+	if (vma->vm_flags & VM_PFNMAP)
+		return 1;
+
+	if (flags & MPOL_MF_LAZY) {
+		/* Similar to task_numa_work, skip inaccessible VMAs */
+		if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
+			change_prot_numa(vma, start, endvma);
+		return 1;
+	}
+
+	if ((flags & MPOL_MF_STRICT) ||
+	    ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
+	     vma_migratable(vma)))
+		/* queue pages from current vma */
+		return 0;
+	return 1;
+}
+
 /*
  * Walk through page tables and collect pages to be migrated.
  *
@@ -656,50 +638,24 @@ static unsigned long change_prot_numa(struct vm_area_struct *vma,
  */
 static int
 queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags, void *private)
-{
-	int err = 0;
-	struct vm_area_struct *vma, *prev;
-
-	vma = find_vma(mm, start);
-	if (!vma)
-		return -EFAULT;
-	prev = NULL;
-	for (; vma && vma->vm_start < end; vma = vma->vm_next) {
-		unsigned long endvma = vma->vm_end;
-
-		if (endvma > end)
-			endvma = end;
-		if (vma->vm_start > start)
-			start = vma->vm_start;
-
-		if (!(flags & MPOL_MF_DISCONTIG_OK)) {
-			if (!vma->vm_next && vma->vm_end < end)
-				return -EFAULT;
-			if (prev && prev->vm_end < vma->vm_start)
-				return -EFAULT;
-		}
-
-		if (flags & MPOL_MF_LAZY) {
-			/* Similar to task_numa_work, skip inaccessible VMAs */
-			if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
-				change_prot_numa(vma, start, endvma);
-			goto next;
-		}
-
-		if ((flags & MPOL_MF_STRICT) ||
-		     ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
-		      vma_migratable(vma))) {
-
-			err = queue_pages_pgd_range(vma, start, endvma, nodes,
-						flags, private);
-			if (err)
-				break;
-		}
-next:
-		prev = vma;
-	}
-	return err;
+		nodemask_t *nodes, unsigned long flags,
+		struct list_head *pagelist)
+{
+	struct queue_pages qp = {
+		.pagelist = pagelist,
+		.flags = flags,
+		.nmask = nodes,
+		.prev = NULL,
+	};
+	struct mm_walk queue_pages_walk = {
+		.hugetlb_entry = queue_pages_hugetlb,
+		.pmd_entry = queue_pages_pte_range,
+		.test_walk = queue_pages_test_walk,
+		.mm = mm,
+		.private = &qp,
+	};
+
+	return walk_page_range(start, end, &queue_pages_walk);
 }
 
 /*
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 11/13] mempolicy: apply page table walker on queue_pages_range()

[Naoya Horiguchi]

queue_pages_range() does page table walking in its own way now, but there
is some code duplicate. This patch applies page table walker to reduce
lines of code.

queue_pages_range() has to do some precheck to determine whether we really
walk over the vma or just skip it. Now we have test_walk() callback in
mm_walk for this purpose, so we can do this replacement cleanly.
queue_pages_test_walk() depends on not only the current vma but also the
previous one, so queue_pages->prev is introduced to remember it.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v4:
- rebase to v3.16-rc3, where the return value of queue_pages_range()
  becomes 0 in success instead of the first found vma, and use -EFAILT
  instead of ERR_PTR() in failure.
---
 mm/mempolicy.c | 228 +++++++++++++++++++++++----------------------------------
 1 file changed, 92 insertions(+), 136 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/mm/mempolicy.c mmotm-2014-11-05-16-01/mm/mempolicy.c
index e58725aff7e9..2c7c4e296386 100644
--- mmotm-2014-11-05-16-01.orig/mm/mempolicy.c
+++ mmotm-2014-11-05-16-01/mm/mempolicy.c
@@ -477,24 +477,34 @@ static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
 static void migrate_page_add(struct page *page, struct list_head *pagelist,
 				unsigned long flags);
 
+struct queue_pages {
+	struct list_head *pagelist;
+	unsigned long flags;
+	nodemask_t *nmask;
+	struct vm_area_struct *prev;
+};
+
 /*
  * Scan through pages checking if pages follow certain conditions,
  * and move them to the pagelist if they do.
  */
-static int queue_pages_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
+static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
+			unsigned long end, struct mm_walk *walk)
 {
-	pte_t *orig_pte;
+	struct vm_area_struct *vma = walk->vma;
+	struct page *page;
+	struct queue_pages *qp = walk->private;
+	unsigned long flags = qp->flags;
+	int nid;
 	pte_t *pte;
 	spinlock_t *ptl;
 
-	orig_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
-	do {
-		struct page *page;
-		int nid;
+	split_huge_page_pmd(vma, addr, pmd);
+	if (pmd_trans_unstable(pmd))
+		return 0;
 
+	pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+	for (; addr != end; pte++, addr += PAGE_SIZE) {
 		if (!pte_present(*pte))
 			continue;
 		page = vm_normal_page(vma, addr, *pte);
@@ -507,114 +517,46 @@ static int queue_pages_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 		if (PageReserved(page))
 			continue;
 		nid = page_to_nid(page);
-		if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
+		if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
 			continue;
 
 		if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL))
-			migrate_page_add(page, private, flags);
-		else
-			break;
-	} while (pte++, addr += PAGE_SIZE, addr != end);
-	pte_unmap_unlock(orig_pte, ptl);
-	return addr != end;
+			migrate_page_add(page, qp->pagelist, flags);
+	}
+	pte_unmap_unlock(pte - 1, ptl);
+	cond_resched();
+	return 0;
 }
 
-static void queue_pages_hugetlb_pmd_range(struct vm_area_struct *vma,
-		pmd_t *pmd, const nodemask_t *nodes, unsigned long flags,
-				    void *private)
+static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
+			       unsigned long addr, unsigned long end,
+			       struct mm_walk *walk)
 {
 #ifdef CONFIG_HUGETLB_PAGE
+	struct queue_pages *qp = walk->private;
+	unsigned long flags = qp->flags;
 	int nid;
 	struct page *page;
 	spinlock_t *ptl;
 	pte_t entry;
 
-	ptl = huge_pte_lock(hstate_vma(vma), vma->vm_mm, (pte_t *)pmd);
-	entry = huge_ptep_get((pte_t *)pmd);
+	ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte);
+	entry = huge_ptep_get(pte);
 	if (!pte_present(entry))
 		goto unlock;
 	page = pte_page(entry);
 	nid = page_to_nid(page);
-	if (node_isset(nid, *nodes) == !!(flags & MPOL_MF_INVERT))
+	if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT))
 		goto unlock;
 	/* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
 	if (flags & (MPOL_MF_MOVE_ALL) ||
 	    (flags & MPOL_MF_MOVE && page_mapcount(page) == 1))
-		isolate_huge_page(page, private);
+		isolate_huge_page(page, qp->pagelist);
 unlock:
 	spin_unlock(ptl);
 #else
 	BUG();
 #endif
-}
-
-static inline int queue_pages_pmd_range(struct vm_area_struct *vma, pud_t *pud,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
-{
-	pmd_t *pmd;
-	unsigned long next;
-
-	pmd = pmd_offset(pud, addr);
-	do {
-		next = pmd_addr_end(addr, end);
-		if (!pmd_present(*pmd))
-			continue;
-		if (pmd_huge(*pmd) && is_vm_hugetlb_page(vma)) {
-			queue_pages_hugetlb_pmd_range(vma, pmd, nodes,
-						flags, private);
-			continue;
-		}
-		split_huge_page_pmd(vma, addr, pmd);
-		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
-			continue;
-		if (queue_pages_pte_range(vma, pmd, addr, next, nodes,
-				    flags, private))
-			return -EIO;
-	} while (pmd++, addr = next, addr != end);
-	return 0;
-}
-
-static inline int queue_pages_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
-{
-	pud_t *pud;
-	unsigned long next;
-
-	pud = pud_offset(pgd, addr);
-	do {
-		next = pud_addr_end(addr, end);
-		if (pud_huge(*pud) && is_vm_hugetlb_page(vma))
-			continue;
-		if (pud_none_or_clear_bad(pud))
-			continue;
-		if (queue_pages_pmd_range(vma, pud, addr, next, nodes,
-				    flags, private))
-			return -EIO;
-	} while (pud++, addr = next, addr != end);
-	return 0;
-}
-
-static inline int queue_pages_pgd_range(struct vm_area_struct *vma,
-		unsigned long addr, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags,
-		void *private)
-{
-	pgd_t *pgd;
-	unsigned long next;
-
-	pgd = pgd_offset(vma->vm_mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(pgd))
-			continue;
-		if (queue_pages_pud_range(vma, pgd, addr, next, nodes,
-				    flags, private))
-			return -EIO;
-	} while (pgd++, addr = next, addr != end);
 	return 0;
 }
 
@@ -647,6 +589,46 @@ static unsigned long change_prot_numa(struct vm_area_struct *vma,
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
+static int queue_pages_test_walk(unsigned long start, unsigned long end,
+				struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
+	struct queue_pages *qp = walk->private;
+	unsigned long endvma = vma->vm_end;
+	unsigned long flags = qp->flags;
+
+	if (endvma > end)
+		endvma = end;
+	if (vma->vm_start > start)
+		start = vma->vm_start;
+
+	if (!(flags & MPOL_MF_DISCONTIG_OK)) {
+		if (!vma->vm_next && vma->vm_end < end)
+			return -EFAULT;
+		if (qp->prev && qp->prev->vm_end < vma->vm_start)
+			return -EFAULT;
+	}
+
+	qp->prev = vma;
+
+	if (vma->vm_flags & VM_PFNMAP)
+		return 1;
+
+	if (flags & MPOL_MF_LAZY) {
+		/* Similar to task_numa_work, skip inaccessible VMAs */
+		if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
+			change_prot_numa(vma, start, endvma);
+		return 1;
+	}
+
+	if ((flags & MPOL_MF_STRICT) ||
+	    ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
+	     vma_migratable(vma)))
+		/* queue pages from current vma */
+		return 0;
+	return 1;
+}
+
 /*
  * Walk through page tables and collect pages to be migrated.
  *
@@ -656,50 +638,24 @@ static unsigned long change_prot_numa(struct vm_area_struct *vma,
  */
 static int
 queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
-		const nodemask_t *nodes, unsigned long flags, void *private)
-{
-	int err = 0;
-	struct vm_area_struct *vma, *prev;
-
-	vma = find_vma(mm, start);
-	if (!vma)
-		return -EFAULT;
-	prev = NULL;
-	for (; vma && vma->vm_start < end; vma = vma->vm_next) {
-		unsigned long endvma = vma->vm_end;
-
-		if (endvma > end)
-			endvma = end;
-		if (vma->vm_start > start)
-			start = vma->vm_start;
-
-		if (!(flags & MPOL_MF_DISCONTIG_OK)) {
-			if (!vma->vm_next && vma->vm_end < end)
-				return -EFAULT;
-			if (prev && prev->vm_end < vma->vm_start)
-				return -EFAULT;
-		}
-
-		if (flags & MPOL_MF_LAZY) {
-			/* Similar to task_numa_work, skip inaccessible VMAs */
-			if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
-				change_prot_numa(vma, start, endvma);
-			goto next;
-		}
-
-		if ((flags & MPOL_MF_STRICT) ||
-		     ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) &&
-		      vma_migratable(vma))) {
-
-			err = queue_pages_pgd_range(vma, start, endvma, nodes,
-						flags, private);
-			if (err)
-				break;
-		}
-next:
-		prev = vma;
-	}
-	return err;
+		nodemask_t *nodes, unsigned long flags,
+		struct list_head *pagelist)
+{
+	struct queue_pages qp = {
+		.pagelist = pagelist,
+		.flags = flags,
+		.nmask = nodes,
+		.prev = NULL,
+	};
+	struct mm_walk queue_pages_walk = {
+		.hugetlb_entry = queue_pages_hugetlb,
+		.pmd_entry = queue_pages_pte_range,
+		.test_walk = queue_pages_test_walk,
+		.mm = mm,
+		.private = &qp,
+	};
+
+	return walk_page_range(start, end, &queue_pages_walk);
 }
 
 /*
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 12/13] mm: /proc/pid/clear_refs: avoid split_huge_page()

[Naoya Horiguchi]

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

Currently pagewalker splits all THP pages on any clear_refs request.  It's
not necessary.  We can handle this on PMD level.

One side effect is that soft dirty will potentially see more dirty memory,
since we will mark whole THP page dirty at once.

Sanity checked with CRIU test suite. More testing is required.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
---
ChangeLog:
- move code for thp to clear_refs_pte_range()
---
 fs/proc/task_mmu.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 3 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index e7d86b97598b..a6c1b75ed3c2 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -744,10 +744,10 @@ struct clear_refs_private {
 	enum clear_refs_types type;
 };
 
+#ifdef CONFIG_MEM_SOFT_DIRTY
 static inline void clear_soft_dirty(struct vm_area_struct *vma,
 		unsigned long addr, pte_t *pte)
 {
-#ifdef CONFIG_MEM_SOFT_DIRTY
 	/*
 	 * The soft-dirty tracker uses #PF-s to catch writes
 	 * to pages, so write-protect the pte as well. See the
@@ -766,9 +766,35 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
 	}
 
 	set_pte_at(vma->vm_mm, addr, pte, ptent);
-#endif
 }
 
+static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
+		unsigned long addr, pmd_t *pmdp)
+{
+	pmd_t pmd = *pmdp;
+
+	pmd = pmd_wrprotect(pmd);
+	pmd = pmd_clear_flags(pmd, _PAGE_SOFT_DIRTY);
+
+	if (vma->vm_flags & VM_SOFTDIRTY)
+		vma->vm_flags &= ~VM_SOFTDIRTY;
+
+	set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+}
+
+#else
+
+static inline void clear_soft_dirty(struct vm_area_struct *vma,
+		unsigned long addr, pte_t *pte)
+{
+}
+
+static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
+		unsigned long addr, pmd_t *pmdp)
+{
+}
+#endif
+
 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 				unsigned long end, struct mm_walk *walk)
 {
@@ -778,7 +804,22 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 	spinlock_t *ptl;
 	struct page *page;
 
-	split_huge_page_pmd(vma, addr, pmd);
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
+			clear_soft_dirty_pmd(vma, addr, pmd);
+			goto out;
+		}
+
+		page = pmd_page(*pmd);
+
+		/* Clear accessed and referenced bits. */
+		pmdp_test_and_clear_young(vma, addr, pmd);
+		ClearPageReferenced(page);
+out:
+		spin_unlock(ptl);
+		return 0;
+	}
+
 	if (pmd_trans_unstable(pmd))
 		return 0;
 
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 12/13] mm: /proc/pid/clear_refs: avoid split_huge_page()

[Naoya Horiguchi]

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

Currently pagewalker splits all THP pages on any clear_refs request.  It's
not necessary.  We can handle this on PMD level.

One side effect is that soft dirty will potentially see more dirty memory,
since we will mark whole THP page dirty at once.

Sanity checked with CRIU test suite. More testing is required.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
---
ChangeLog:
- move code for thp to clear_refs_pte_range()
---
 fs/proc/task_mmu.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 3 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
index e7d86b97598b..a6c1b75ed3c2 100644
--- mmotm-2014-11-05-16-01.orig/fs/proc/task_mmu.c
+++ mmotm-2014-11-05-16-01/fs/proc/task_mmu.c
@@ -744,10 +744,10 @@ struct clear_refs_private {
 	enum clear_refs_types type;
 };
 
+#ifdef CONFIG_MEM_SOFT_DIRTY
 static inline void clear_soft_dirty(struct vm_area_struct *vma,
 		unsigned long addr, pte_t *pte)
 {
-#ifdef CONFIG_MEM_SOFT_DIRTY
 	/*
 	 * The soft-dirty tracker uses #PF-s to catch writes
 	 * to pages, so write-protect the pte as well. See the
@@ -766,9 +766,35 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
 	}
 
 	set_pte_at(vma->vm_mm, addr, pte, ptent);
-#endif
 }
 
+static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
+		unsigned long addr, pmd_t *pmdp)
+{
+	pmd_t pmd = *pmdp;
+
+	pmd = pmd_wrprotect(pmd);
+	pmd = pmd_clear_flags(pmd, _PAGE_SOFT_DIRTY);
+
+	if (vma->vm_flags & VM_SOFTDIRTY)
+		vma->vm_flags &= ~VM_SOFTDIRTY;
+
+	set_pmd_at(vma->vm_mm, addr, pmdp, pmd);
+}
+
+#else
+
+static inline void clear_soft_dirty(struct vm_area_struct *vma,
+		unsigned long addr, pte_t *pte)
+{
+}
+
+static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
+		unsigned long addr, pmd_t *pmdp)
+{
+}
+#endif
+
 static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 				unsigned long end, struct mm_walk *walk)
 {
@@ -778,7 +804,22 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
 	spinlock_t *ptl;
 	struct page *page;
 
-	split_huge_page_pmd(vma, addr, pmd);
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+		if (cp->type == CLEAR_REFS_SOFT_DIRTY) {
+			clear_soft_dirty_pmd(vma, addr, pmd);
+			goto out;
+		}
+
+		page = pmd_page(*pmd);
+
+		/* Clear accessed and referenced bits. */
+		pmdp_test_and_clear_young(vma, addr, pmd);
+		ClearPageReferenced(page);
+out:
+		spin_unlock(ptl);
+		return 0;
+	}
+
 	if (pmd_trans_unstable(pmd))
 		return 0;
 
-- 
2.2.0.rc0.2.gf745acb

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[PATCH -mm v7 13/13] mincore: apply page table walker on do_mincore()

[Naoya Horiguchi]

This patch makes do_mincore() use walk_page_vma(), which reduces many lines
of code by using common page table walk code.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v5:
- fix buffer overflow

ChangeLog v4:
- remove redundant vma

ChangeLog v3:
- add NULL vma check in mincore_unmapped_range()
- don't use pte_entry()

ChangeLog v2:
- change type of args of callbacks to void *
- move definition of mincore_walk to the start of the function to fix compiler
  warning
---
 mm/huge_memory.c |  20 -------
 mm/mincore.c     | 169 +++++++++++++++++++------------------------------------
 2 files changed, 59 insertions(+), 130 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/mm/huge_memory.c mmotm-2014-11-05-16-01/mm/huge_memory.c
index ff1ecea8c0d7..a81a0b917068 100644
--- mmotm-2014-11-05-16-01.orig/mm/huge_memory.c
+++ mmotm-2014-11-05-16-01/mm/huge_memory.c
@@ -1422,26 +1422,6 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 	return ret;
 }
 
-int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
-		unsigned long addr, unsigned long end,
-		unsigned char *vec)
-{
-	spinlock_t *ptl;
-	int ret = 0;
-
-	if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
-		/*
-		 * All logical pages in the range are present
-		 * if backed by a huge page.
-		 */
-		spin_unlock(ptl);
-		memset(vec, 1, (end - addr) >> PAGE_SHIFT);
-		ret = 1;
-	}
-
-	return ret;
-}
-
 int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
 		  unsigned long old_addr,
 		  unsigned long new_addr, unsigned long old_end,
diff --git mmotm-2014-11-05-16-01.orig/mm/mincore.c mmotm-2014-11-05-16-01/mm/mincore.c
index 725c80961048..0e548fbce19e 100644
--- mmotm-2014-11-05-16-01.orig/mm/mincore.c
+++ mmotm-2014-11-05-16-01/mm/mincore.c
@@ -19,38 +19,26 @@
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 
-static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
-				unsigned long addr, unsigned long end,
-				unsigned char *vec)
+static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
+			unsigned long end, struct mm_walk *walk)
 {
+	int err = 0;
 #ifdef CONFIG_HUGETLB_PAGE
-	struct hstate *h;
+	unsigned char present;
+	unsigned char *vec = walk->private;
 
-	h = hstate_vma(vma);
-	while (1) {
-		unsigned char present;
-		pte_t *ptep;
-		/*
-		 * Huge pages are always in RAM for now, but
-		 * theoretically it needs to be checked.
-		 */
-		ptep = huge_pte_offset(current->mm,
-				       addr & huge_page_mask(h));
-		present = ptep && !huge_pte_none(huge_ptep_get(ptep));
-		while (1) {
-			*vec = present;
-			vec++;
-			addr += PAGE_SIZE;
-			if (addr == end)
-				return;
-			/* check hugepage border */
-			if (!(addr & ~huge_page_mask(h)))
-				break;
-		}
-	}
+	/*
+	 * Hugepages under user process are always in RAM and never
+	 * swapped out, but theoretically it needs to be checked.
+	 */
+	present = pte && !huge_pte_none(huge_ptep_get(pte));
+	for (; addr != end; vec++, addr += PAGE_SIZE)
+		*vec = present;
+	walk->private = vec;
 #else
 	BUG();
 #endif
+	return err;
 }
 
 /*
@@ -94,14 +82,15 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
 	return present;
 }
 
-static void mincore_unmapped_range(struct vm_area_struct *vma,
-				unsigned long addr, unsigned long end,
-				unsigned char *vec)
+static int mincore_unmapped_range(unsigned long addr, unsigned long end,
+				   struct mm_walk *walk)
 {
+	struct vm_area_struct *vma = walk->vma;
+	unsigned char *vec = walk->private;
 	unsigned long nr = (end - addr) >> PAGE_SHIFT;
 	int i;
 
-	if (vma->vm_file) {
+	if (vma && vma->vm_file) {
 		pgoff_t pgoff;
 
 		pgoff = linear_page_index(vma, addr);
@@ -111,25 +100,40 @@ static void mincore_unmapped_range(struct vm_area_struct *vma,
 		for (i = 0; i < nr; i++)
 			vec[i] = 0;
 	}
+	walk->private += nr;
+	return 0;
 }
 
-static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
+static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+			struct mm_walk *walk)
 {
-	unsigned long next;
 	spinlock_t *ptl;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *ptep;
 
-	ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
-	do {
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+		memset(walk->private, 1, (end - addr) >> PAGE_SHIFT);
+		walk->private += (end - addr) >> PAGE_SHIFT;
+		spin_unlock(ptl);
+		return 0;
+	}
+
+	if (pmd_trans_unstable(pmd)) {
+		mincore_unmapped_range(addr, end, walk);
+		return 0;
+	}
+
+	ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+	for (; addr != end; ptep++, addr += PAGE_SIZE) {
 		pte_t pte = *ptep;
 		pgoff_t pgoff;
+		unsigned char *vec = walk->private;
 
-		next = addr + PAGE_SIZE;
-		if (pte_none(pte))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else if (pte_present(pte))
+		if (pte_none(pte)) {
+			mincore_unmapped_range(addr, addr + PAGE_SIZE, walk);
+			continue;
+		}
+		if (pte_present(pte))
 			*vec = 1;
 		else if (pte_file(pte)) {
 			pgoff = pte_to_pgoff(pte);
@@ -151,70 +155,11 @@ static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 #endif
 			}
 		}
-		vec++;
-	} while (ptep++, addr = next, addr != end);
+		walk->private++;
+	}
 	pte_unmap_unlock(ptep - 1, ptl);
-}
-
-static void mincore_pmd_range(struct vm_area_struct *vma, pud_t *pud,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
-{
-	unsigned long next;
-	pmd_t *pmd;
-
-	pmd = pmd_offset(pud, addr);
-	do {
-		next = pmd_addr_end(addr, end);
-		if (pmd_trans_huge(*pmd)) {
-			if (mincore_huge_pmd(vma, pmd, addr, next, vec)) {
-				vec += (next - addr) >> PAGE_SHIFT;
-				continue;
-			}
-			/* fall through */
-		}
-		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else
-			mincore_pte_range(vma, pmd, addr, next, vec);
-		vec += (next - addr) >> PAGE_SHIFT;
-	} while (pmd++, addr = next, addr != end);
-}
-
-static void mincore_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
-{
-	unsigned long next;
-	pud_t *pud;
-
-	pud = pud_offset(pgd, addr);
-	do {
-		next = pud_addr_end(addr, end);
-		if (pud_none_or_clear_bad(pud))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else
-			mincore_pmd_range(vma, pud, addr, next, vec);
-		vec += (next - addr) >> PAGE_SHIFT;
-	} while (pud++, addr = next, addr != end);
-}
-
-static void mincore_page_range(struct vm_area_struct *vma,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
-{
-	unsigned long next;
-	pgd_t *pgd;
-
-	pgd = pgd_offset(vma->vm_mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(pgd))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else
-			mincore_pud_range(vma, pgd, addr, next, vec);
-		vec += (next - addr) >> PAGE_SHIFT;
-	} while (pgd++, addr = next, addr != end);
+	cond_resched();
+	return 0;
 }
 
 /*
@@ -226,18 +171,22 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
 {
 	struct vm_area_struct *vma;
 	unsigned long end;
+	int err;
+	struct mm_walk mincore_walk = {
+		.pmd_entry = mincore_pte_range,
+		.pte_hole = mincore_unmapped_range,
+		.hugetlb_entry = mincore_hugetlb,
+		.private = vec,
+	};
 
 	vma = find_vma(current->mm, addr);
 	if (!vma || addr < vma->vm_start)
 		return -ENOMEM;
-
+	mincore_walk.mm = vma->vm_mm;
 	end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));
-
-	if (is_vm_hugetlb_page(vma))
-		mincore_hugetlb_page_range(vma, addr, end, vec);
-	else
-		mincore_page_range(vma, addr, end, vec);
-
+	err = walk_page_range(addr, end, &mincore_walk);
+	if (err < 0)
+		return err;
 	return (end - addr) >> PAGE_SHIFT;
 }
 
-- 
2.2.0.rc0.2.gf745acb

[PATCH -mm v7 13/13] mincore: apply page table walker on do_mincore()

[Naoya Horiguchi]

This patch makes do_mincore() use walk_page_vma(), which reduces many lines
of code by using common page table walk code.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
---
ChangeLog v5:
- fix buffer overflow

ChangeLog v4:
- remove redundant vma

ChangeLog v3:
- add NULL vma check in mincore_unmapped_range()
- don't use pte_entry()

ChangeLog v2:
- change type of args of callbacks to void *
- move definition of mincore_walk to the start of the function to fix compiler
  warning
---
 mm/huge_memory.c |  20 -------
 mm/mincore.c     | 169 +++++++++++++++++++------------------------------------
 2 files changed, 59 insertions(+), 130 deletions(-)

diff --git mmotm-2014-11-05-16-01.orig/mm/huge_memory.c mmotm-2014-11-05-16-01/mm/huge_memory.c
index ff1ecea8c0d7..a81a0b917068 100644
--- mmotm-2014-11-05-16-01.orig/mm/huge_memory.c
+++ mmotm-2014-11-05-16-01/mm/huge_memory.c
@@ -1422,26 +1422,6 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 	return ret;
 }
 
-int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
-		unsigned long addr, unsigned long end,
-		unsigned char *vec)
-{
-	spinlock_t *ptl;
-	int ret = 0;
-
-	if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
-		/*
-		 * All logical pages in the range are present
-		 * if backed by a huge page.
-		 */
-		spin_unlock(ptl);
-		memset(vec, 1, (end - addr) >> PAGE_SHIFT);
-		ret = 1;
-	}
-
-	return ret;
-}
-
 int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
 		  unsigned long old_addr,
 		  unsigned long new_addr, unsigned long old_end,
diff --git mmotm-2014-11-05-16-01.orig/mm/mincore.c mmotm-2014-11-05-16-01/mm/mincore.c
index 725c80961048..0e548fbce19e 100644
--- mmotm-2014-11-05-16-01.orig/mm/mincore.c
+++ mmotm-2014-11-05-16-01/mm/mincore.c
@@ -19,38 +19,26 @@
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 
-static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
-				unsigned long addr, unsigned long end,
-				unsigned char *vec)
+static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
+			unsigned long end, struct mm_walk *walk)
 {
+	int err = 0;
 #ifdef CONFIG_HUGETLB_PAGE
-	struct hstate *h;
+	unsigned char present;
+	unsigned char *vec = walk->private;
 
-	h = hstate_vma(vma);
-	while (1) {
-		unsigned char present;
-		pte_t *ptep;
-		/*
-		 * Huge pages are always in RAM for now, but
-		 * theoretically it needs to be checked.
-		 */
-		ptep = huge_pte_offset(current->mm,
-				       addr & huge_page_mask(h));
-		present = ptep && !huge_pte_none(huge_ptep_get(ptep));
-		while (1) {
-			*vec = present;
-			vec++;
-			addr += PAGE_SIZE;
-			if (addr == end)
-				return;
-			/* check hugepage border */
-			if (!(addr & ~huge_page_mask(h)))
-				break;
-		}
-	}
+	/*
+	 * Hugepages under user process are always in RAM and never
+	 * swapped out, but theoretically it needs to be checked.
+	 */
+	present = pte && !huge_pte_none(huge_ptep_get(pte));
+	for (; addr != end; vec++, addr += PAGE_SIZE)
+		*vec = present;
+	walk->private = vec;
 #else
 	BUG();
 #endif
+	return err;
 }
 
 /*
@@ -94,14 +82,15 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
 	return present;
 }
 
-static void mincore_unmapped_range(struct vm_area_struct *vma,
-				unsigned long addr, unsigned long end,
-				unsigned char *vec)
+static int mincore_unmapped_range(unsigned long addr, unsigned long end,
+				   struct mm_walk *walk)
 {
+	struct vm_area_struct *vma = walk->vma;
+	unsigned char *vec = walk->private;
 	unsigned long nr = (end - addr) >> PAGE_SHIFT;
 	int i;
 
-	if (vma->vm_file) {
+	if (vma && vma->vm_file) {
 		pgoff_t pgoff;
 
 		pgoff = linear_page_index(vma, addr);
@@ -111,25 +100,40 @@ static void mincore_unmapped_range(struct vm_area_struct *vma,
 		for (i = 0; i < nr; i++)
 			vec[i] = 0;
 	}
+	walk->private += nr;
+	return 0;
 }
 
-static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
+static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+			struct mm_walk *walk)
 {
-	unsigned long next;
 	spinlock_t *ptl;
+	struct vm_area_struct *vma = walk->vma;
 	pte_t *ptep;
 
-	ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
-	do {
+	if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
+		memset(walk->private, 1, (end - addr) >> PAGE_SHIFT);
+		walk->private += (end - addr) >> PAGE_SHIFT;
+		spin_unlock(ptl);
+		return 0;
+	}
+
+	if (pmd_trans_unstable(pmd)) {
+		mincore_unmapped_range(addr, end, walk);
+		return 0;
+	}
+
+	ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
+	for (; addr != end; ptep++, addr += PAGE_SIZE) {
 		pte_t pte = *ptep;
 		pgoff_t pgoff;
+		unsigned char *vec = walk->private;
 
-		next = addr + PAGE_SIZE;
-		if (pte_none(pte))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else if (pte_present(pte))
+		if (pte_none(pte)) {
+			mincore_unmapped_range(addr, addr + PAGE_SIZE, walk);
+			continue;
+		}
+		if (pte_present(pte))
 			*vec = 1;
 		else if (pte_file(pte)) {
 			pgoff = pte_to_pgoff(pte);
@@ -151,70 +155,11 @@ static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 #endif
 			}
 		}
-		vec++;
-	} while (ptep++, addr = next, addr != end);
+		walk->private++;
+	}
 	pte_unmap_unlock(ptep - 1, ptl);
-}
-
-static void mincore_pmd_range(struct vm_area_struct *vma, pud_t *pud,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
-{
-	unsigned long next;
-	pmd_t *pmd;
-
-	pmd = pmd_offset(pud, addr);
-	do {
-		next = pmd_addr_end(addr, end);
-		if (pmd_trans_huge(*pmd)) {
-			if (mincore_huge_pmd(vma, pmd, addr, next, vec)) {
-				vec += (next - addr) >> PAGE_SHIFT;
-				continue;
-			}
-			/* fall through */
-		}
-		if (pmd_none_or_trans_huge_or_clear_bad(pmd))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else
-			mincore_pte_range(vma, pmd, addr, next, vec);
-		vec += (next - addr) >> PAGE_SHIFT;
-	} while (pmd++, addr = next, addr != end);
-}
-
-static void mincore_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
-{
-	unsigned long next;
-	pud_t *pud;
-
-	pud = pud_offset(pgd, addr);
-	do {
-		next = pud_addr_end(addr, end);
-		if (pud_none_or_clear_bad(pud))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else
-			mincore_pmd_range(vma, pud, addr, next, vec);
-		vec += (next - addr) >> PAGE_SHIFT;
-	} while (pud++, addr = next, addr != end);
-}
-
-static void mincore_page_range(struct vm_area_struct *vma,
-			unsigned long addr, unsigned long end,
-			unsigned char *vec)
-{
-	unsigned long next;
-	pgd_t *pgd;
-
-	pgd = pgd_offset(vma->vm_mm, addr);
-	do {
-		next = pgd_addr_end(addr, end);
-		if (pgd_none_or_clear_bad(pgd))
-			mincore_unmapped_range(vma, addr, next, vec);
-		else
-			mincore_pud_range(vma, pgd, addr, next, vec);
-		vec += (next - addr) >> PAGE_SHIFT;
-	} while (pgd++, addr = next, addr != end);
+	cond_resched();
+	return 0;
 }
 
 /*
@@ -226,18 +171,22 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
 {
 	struct vm_area_struct *vma;
 	unsigned long end;
+	int err;
+	struct mm_walk mincore_walk = {
+		.pmd_entry = mincore_pte_range,
+		.pte_hole = mincore_unmapped_range,
+		.hugetlb_entry = mincore_hugetlb,
+		.private = vec,
+	};
 
 	vma = find_vma(current->mm, addr);
 	if (!vma || addr < vma->vm_start)
 		return -ENOMEM;
-
+	mincore_walk.mm = vma->vm_mm;
 	end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));
-
-	if (is_vm_hugetlb_page(vma))
-		mincore_hugetlb_page_range(vma, addr, end, vec);
-	else
-		mincore_page_range(vma, addr, end, vec);
-
+	err = walk_page_range(addr, end, &mincore_walk);
+	if (err < 0)
+		return err;
 	return (end - addr) >> PAGE_SHIFT;
 }
 
-- 
2.2.0.rc0.2.gf745acb

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Re: [PATCH -mm v7 00/13] pagewalk: improve vma handling, apply to new users

[Kirill A. Shutemov]

On Fri, Nov 07, 2014 at 07:01:51AM +0000, Naoya Horiguchi wrote:
> This series is ver.7 of page table walker patchset.
> 
> I apologize about my long delay since previous version (I have moved to
> Japan last month and no machine access for a while.)
> I just rebased this onto mmotm-2014-11-05-16-01. I had some conflicts but
> the resolution was not hard.
> Trinity showed no bug at least in my environment.

Andrew, any chance you'll find time for the patchset?

-- 
 Kirill A. Shutemov

Re: [PATCH -mm v7 00/13] pagewalk: improve vma handling, apply to new users

[Kirill A. Shutemov]

On Fri, Nov 07, 2014 at 07:01:51AM +0000, Naoya Horiguchi wrote:
> This series is ver.7 of page table walker patchset.
> 
> I apologize about my long delay since previous version (I have moved to
> Japan last month and no machine access for a while.)
> I just rebased this onto mmotm-2014-11-05-16-01. I had some conflicts but
> the resolution was not hard.
> Trinity showed no bug at least in my environment.

Andrew, any chance you'll find time for the patchset?

-- 
 Kirill A. Shutemov

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Re: [PATCH -mm v7 00/13] pagewalk: improve vma handling, apply to new users

[Andrew Morton]

On Fri, 16 Jan 2015 18:32:17 +0200 "Kirill A. Shutemov" <kirill@shutemov.name> wrote:

> On Fri, Nov 07, 2014 at 07:01:51AM +0000, Naoya Horiguchi wrote:
> > This series is ver.7 of page table walker patchset.
> > 
> > I apologize about my long delay since previous version (I have moved to
> > Japan last month and no machine access for a while.)
> > I just rebased this onto mmotm-2014-11-05-16-01. I had some conflicts but
> > the resolution was not hard.
> > Trinity showed no bug at least in my environment.
> 
> Andrew, any chance you'll find time for the patchset?
> 

That was 2+ months ago - the patches have decayed somewhat.  I'm only
seeing a few rejects so I'll have a play with them, see how it all
looks.

Re: [PATCH -mm v7 00/13] pagewalk: improve vma handling, apply to new users

[Andrew Morton]

On Fri, 16 Jan 2015 18:32:17 +0200 "Kirill A. Shutemov" <kirill@shutemov.name> wrote:

> On Fri, Nov 07, 2014 at 07:01:51AM +0000, Naoya Horiguchi wrote:
> > This series is ver.7 of page table walker patchset.
> > 
> > I apologize about my long delay since previous version (I have moved to
> > Japan last month and no machine access for a while.)
> > I just rebased this onto mmotm-2014-11-05-16-01. I had some conflicts but
> > the resolution was not hard.
> > Trinity showed no bug at least in my environment.
> 
> Andrew, any chance you'll find time for the patchset?
> 

That was 2+ months ago - the patches have decayed somewhat.  I'm only
seeing a few rejects so I'll have a play with them, see how it all
looks.


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[PATCH -mm 14/13] mm: pagewalk: fix misbehavior of walk_page_range for vma(VM_PFNMAP) (Re: [PATCH -mm v7 02/13] pagewalk: improve vma handling)

[Naoya Horiguchi]

Hi Andrew,

On Thu, Jan 22, 2015 at 03:22:05PM -0800, Andrew Morton wrote:
> On Fri, 7 Nov 2014 07:01:55 +0000 Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> wrote:
> 
> > Current implementation of page table walker has a fundamental problem
> > in vma handling, which started when we tried to handle vma(VM_HUGETLB).
> > Because it's done in pgd loop, considering vma boundary makes code
> > complicated and bug-prone.
> > 
> > >From the users viewpoint, some user checks some vma-related condition to
> > determine whether the user really does page walk over the vma.
> > 
> > In order to solve these, this patch moves vma check outside pgd loop and
> > introduce a new callback ->test_walk().
> 
> I had to revert
> mm-pagewalk-call-pte_hole-for-vm_pfnmap-during-walk_page_range.patch.patch
> to apply this.  Could you please work out how to reapply it after your
> patch?

I revised Shiraz's patch on top of this series.
My testing confirmed that both of the overrunning problem and "storing data
in wrong index" problem are solved with it.

Thanks,
Naoya Horiguchi
---
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Date: Fri, 23 Jan 2015 16:58:12 +0900
Subject: [PATCH] mm: pagewalk: fix misbehavior of walk_page_range for
 vma(VM_PFNMAP)

walk_page_range() silently skips vma having VM_PFNMAP set, which leads to
undesirable behaviour at client end (who called walk_page_range).  For
example for pagemap_read(), when no callbacks are called against VM_PFNMAP
vma, pagemap_read() may prepare pagemap data for next virtual address range
at wrong index. That could confuse and/or break userspace applications.

This patch avoid this misbehavior caused by vma(VM_PFNMAP) like follows:
- for pagemap_read() which has its own ->pte_hole(), call the ->pte_hole()
  over vma(VM_PFNMAP),
- for clear_refs and queue_pages which have their own ->tests_walk,
  just return 1 and skip vma(VM_PFNMAP). This is no problem because
  these are not interested in hole regions,
- for other callers, just skip the vma(VM_PFNMAP) as a default behavior.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Shiraz Hashim <shashim@codeaurora.org>
---
 fs/proc/task_mmu.c |  3 +++
 mm/mempolicy.c     |  3 +++
 mm/pagewalk.c      | 21 +++++++++++++--------
 3 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index dcee0ad53fae..91753dd283f0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -844,6 +844,9 @@ static int clear_refs_test_walk(unsigned long start, unsigned long end,
 	struct clear_refs_private *cp = walk->private;
 	struct vm_area_struct *vma = walk->vma;
 
+	if (vma->vm_flags & VM_PFNMAP)
+		return 1;
+
 	/*
 	 * Writing 1 to /proc/pid/clear_refs affects all pages.
 	 * Writing 2 to /proc/pid/clear_refs only affects anonymous pages.
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 326474de80bd..66e7141c2bfd 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -591,6 +591,9 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
 	unsigned long endvma = vma->vm_end;
 	unsigned long flags = qp->flags;
 
+	if (vma->vm_flags & VM_PFNMAP)
+		return 1;
+
 	if (endvma > end)
 		endvma = end;
 	if (vma->vm_start > start)
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 4c9a653ba563..75c1f2878519 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -35,7 +35,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
 	do {
 again:
 		next = pmd_addr_end(addr, end);
-		if (pmd_none(*pmd)) {
+		if (pmd_none(*pmd) || !walk->vma) {
 			if (walk->pte_hole)
 				err = walk->pte_hole(addr, next, walk);
 			if (err)
@@ -165,9 +165,6 @@ static int walk_hugetlb_range(unsigned long addr, unsigned long end,
  * or skip it via the returned value. Return 0 if we do walk over the
  * current vma, and return 1 if we skip the vma. Negative values means
  * error, where we abort the current walk.
- *
- * Default check (only VM_PFNMAP check for now) is used when the caller
- * doesn't define test_walk() callback.
  */
 static int walk_page_test(unsigned long start, unsigned long end,
 			struct mm_walk *walk)
@@ -178,11 +175,19 @@ static int walk_page_test(unsigned long start, unsigned long end,
 		return walk->test_walk(start, end, walk);
 
 	/*
-	 * Do not walk over vma(VM_PFNMAP), because we have no valid struct
-	 * page backing a VM_PFNMAP range. See also commit a9ff785e4437.
+	 * vma(VM_PFNMAP) doesn't have any valid struct pages behind VM_PFNMAP
+	 * range, so we don't walk over it as we do for normal vmas. However,
+	 * Some callers are interested in handling hole range and they don't
+	 * want to just ignore any single address range. Such users certainly
+	 * define their ->pte_hole() callbacks, so let's delegate them to handle
+	 * vma(VM_PFNMAP).
 	 */
-	if (vma->vm_flags & VM_PFNMAP)
-		return 1;
+	if (vma->vm_flags & VM_PFNMAP) {
+		int err = 1;
+		if (walk->pte_hole)
+			err = walk->pte_hole(start, end, walk);
+		return err ? err : 1;
+	}
 	return 0;
 }
 
-- 
1.9.3

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