mm/ksm: fix ksm_zero_pages accounting

We normally ksm_zero_pages++ in ksmd when page is merged with zero page,
but ksm_zero_pages-- is done from page tables side, where there is no any
accessing protection of ksm_zero_pages.

So we can read very exceptional value of ksm_zero_pages in rare cases,
such as -1, which is very confusing to users.

Fix it by changing to use atomic_long_t, and the same case with the
mm->ksm_zero_pages.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: e2942062e01d ("ksm: count all zero pages placed by KSM")
Fixes: 6080d19f0704 ("ksm: add ksm zero pages for each process")
Signed-off-by: Chengming Zhou <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ran Xiaokai <[email protected]>
Cc: Stefan Roesch <[email protected]>
Cc: xu xin <[email protected]>
Cc: Yang Yang <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions