[PATCH 3.16 135/366] ksm: add cond_resched() to the rmap_walks

[Ben Hutchings]

3.16.61-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Andrea Arcangeli <aarcange@xxxxxxxxxx>

commit ad12695f177c3403a64348b42718faf9727fe358 upstream.

While at it add it to the file and anon walks too.

Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Petr Holasek <pholasek@xxxxxxxxxx>
Acked-by: Davidlohr Bueso <dbueso@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 mm/ksm.c  | 2 ++
 mm/rmap.c | 4 ++++
 2 files changed, 6 insertions(+)

--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1915,9 +1915,11 @@ again:
 		struct anon_vma_chain *vmac;
 		struct vm_area_struct *vma;
 
+		cond_resched();
 		anon_vma_lock_read(anon_vma);
 		anon_vma_interval_tree_foreach(vmac, &anon_vma->rb_root,
 					       0, ULONG_MAX) {
+			cond_resched();
 			vma = vmac->vma;
 			if (rmap_item->address < vma->vm_start ||
 			    rmap_item->address >= vma->vm_end)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1486,6 +1486,8 @@ static int rmap_walk_anon(struct page *p
 		struct vm_area_struct *vma = avc->vma;
 		unsigned long address = vma_address(page, vma);
 
+		cond_resched();
+
 		if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
 			continue;
 
@@ -1533,6 +1535,8 @@ static int rmap_walk_file(struct page *p
 	vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
 		unsigned long address = vma_address(page, vma);
 
+		cond_resched();
+
 		if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg))
 			continue;