[34-longterm 093/209] nommu: yield CPU while disposing VM

[Paul Gortmaker]

From: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>

  =====================================================================
  | This is a commit scheduled for the next v2.6.34 longterm release. |
  | If you see a problem with using this for longterm, please comment.|
  =====================================================================

commit 04c3496152394d17e3bc2316f9731ee3e8a026bc upstream.

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@xxxxxxxxxxxxxxx>
Cc: Greg Ungerer <gerg@xxxxxxxxxxxx>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 mm/nommu.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/mm/nommu.c b/mm/nommu.c
index 28994ee..1fc13c0 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1669,6 +1669,7 @@ void exit_mmap(struct mm_struct *mm)
 		mm->mmap = vma->vm_next;
 		delete_vma_from_mm(vma);
 		delete_vma(mm, vma);
+		cond_resched();
 	}
 
 	kleave("");
-- 
1.7.4.4

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