tree d9f1d2493f86e14e0a3ae3013606655973643e33
parent 717a2621b5103b90f2028137c2964f7a3acac8ba
author Jin Dongming <jin.dongming@np.css.fujitsu.com> 1290580631 +0900
committer Andi Kleen <ak@linux.intel.com> 1290594939 +0100

Fix write/read_hugepage() for copy-on-write.

When the cowflag is valid, child process should copy all the hugepage of
its parent. But now no matter what cowflag is, the child process will not do
copy-on-write operation. It is because the parameter(size==0) of
write_hugepage() make write_hugepage() do nothing.

This problem is introduced by
  commit c6a4c3d950385063db705e520bc9b6cda9587f57
  Author: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

With this patch, the state of parent and child processes will be like following:
        Before this patch                        After this patch
NO-COW  Parent and child processes are killed.   Same as before.
COW     Parent and child processes are killed.   Only parent process is killed.
(Here process is killed by memory-failure.)

Signed-off-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>