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Commit 5c64f52a authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds
Browse files

clear_refs: remove clear_refs_private->vma and introduce clear_refs_test_walk() 



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: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 14eb6fdd

fs/proc/task_mmu.c

+22 −24
Original line number Diff line number Diff line
@@ -736,7 +736,6 @@ enum clear_refs_types { 
};



struct clear_refs_private {

	struct vm_area_struct *vma;

	enum clear_refs_types type;

};
@@ -767,7 +766,7 @@ 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;
@@ -801,6 +800,25 @@ 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)

{
@@ -841,6 +859,7 @@ 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,

		};
@@ -860,28 +879,7 @@ 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);