On Wed, Dec 12, 2012 at 01:36:36PM +0800, Bob Liu wrote:

On Mon, Dec 3, 2012 at 9:02 PM, Jiri Slaby [off-list ref] wrote:

quoted

On 11/30/2012 04:03 PM, Kirill A. Shutemov wrote:

quoted

From: "Kirill A. Shutemov" <redacted>

Hi Jiri,

Sorry for late answer. It took time to reproduce and debug the issue.

Could you test two patches below by thread. I expect it to fix both
issues: put_huge_zero_page() and Bad rss-counter state.

Hi, yes, since applying the patches on the last Thu, it didn't recur.

quoted

Kirill A. Shutemov (2):
  thp: fix anononymous page accounting in fallback path for COW of HZP
  thp: avoid race on multiple parallel page faults to the same page

 mm/huge_memory.c | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

I still saw this bug on 3.7.0-rc8, but it's hard to reproduce it.
It appears only once.

I guess the patch you've posted fixes the issue, right?

It's useful to enable debug_cow to test fallback path:

echo 1 > /sys/kernel/mm/transparent_hugepage/debug_cow

-- 
 Kirill A. Shutemov