linux-kernel - [PATCH 1/1] pagemap clear_refs: modify to specify anon or mapped vma clearing

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Date:	Thu, 23 Jul 2009 20:57:22 -0700
From:	"Moussa A. Ba" <moussa.a.ba@...il.com>
To:	linux-kernel@...r.kernel.org
CC:	akpm@...ux-foundation.org, adobriyan@...il.com, mpm@...enic.com,
	mel@....ul.ie, yinghan@...gle.com, npiggin@...e.de,
	jaredeh@...il.com, moussa.a.ba@...il.com
Subject: [PATCH 1/1] pagemap clear_refs: modify to specify anon or mapped
 vma clearing


Signed-off-by: Jared E. Hulbert <jaredeh@...il.com>
Signed-off-by: Moussa Ba <moussa.a.ba@...il.com>
--- a/fs/proc/task_mmu.c	2009-07-21 14:30:01.000000000 -0700
+++ b/fs/proc/task_mmu.c	2009-07-21 14:32:56.000000000 -0700
@@ -461,6 +461,33 @@
  	cond_resched();
  	return 0;
  }
+static void walk_vma_area(struct mm_walk *this_walk, struct 
vm_area_struct *vma,
+						int type)
+{
+	switch (type) {
+		/* Clear Anon VMAs only */
+	case 1:
+		if (!is_vm_hugetlb_page(vma) && !vma->vm_file)
+			walk_page_range(vma->vm_start,
+					vma->vm_end,
+					this_walk);
+		break;
+		/* Clear Mapped VMAs only */
+	case 2:
+		if (!is_vm_hugetlb_page(vma) && vma->vm_file)
+			walk_page_range(vma->vm_start,
+					vma->vm_end,
+					this_walk);
+		break;
+		/* Clear All VMAs */
+	default:
+		if (!is_vm_hugetlb_page(vma))
+			walk_page_range(vma->vm_start,
+					vma->vm_end,
+					this_walk);
+		break;
+	}
+}

  static ssize_t clear_refs_write(struct file *file, const char __user * 
buf,
  				size_t count, loff_t * ppos)
@@ -469,13 +496,15 @@
  	char buffer[PROC_NUMBUF], *end;
  	struct mm_struct *mm;
  	struct vm_area_struct *vma;
+	int type;

  	memset(buffer, 0, sizeof(buffer));
  	if (count > sizeof(buffer) - 1)
  		count = sizeof(buffer) - 1;
  	if (copy_from_user(buffer, buf, count))
  		return -EFAULT;
-	if (!simple_strtol(buffer, &end, 0))
+	type = simple_strtol(buffer, &end, 0);
+	if (!type)
  		return -EINVAL;
  	if (*end == '\n')
  		end++;
@@ -491,9 +520,7 @@
  		down_read(&mm->mmap_sem);
  		for (vma = mm->mmap; vma; vma = vma->vm_next) {
  			clear_refs_walk.private = vma;
-			if (!is_vm_hugetlb_page(vma))
-				walk_page_range(vma->vm_start, vma->vm_end,
-						&clear_refs_walk);
+			walk_vma_area(&clear_refs_walk, vma, type);
  		}
  		flush_tlb_mm(mm);
  		up_read(&mm->mmap_sem);
--
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