nommu: yield CPU while disposing VM

Depending on processor speed, page size, and the amount of memory a
process is allowed to amass, cleanup of a large VM may freeze the system
for many seconds.  This can result in a watchdog timeout.

Make sure other tasks receive some service when cleaning up large VMs.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index 3613517c7592..27a9ac588516 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1717,6 +1717,7 @@ void exit_mmap(struct mm_struct *mm)
                 mm->mmap = vma->vm_next;
                 delete_vma_from_mm(vma);
                 delete_vma(mm, vma);
+                cond_resched();
         }
 
         kleave("");