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@xxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
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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