HWPOISON: comment dirty swapcache pages

AK: Improve comment

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/mm/memory.c b/mm/memory.c
index a54b2c498444..db09106ed44b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2553,6 +2553,10 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
                 ret = VM_FAULT_MAJOR;
                 count_vm_event(PGMAJFAULT);
         } else if (PageHWPoison(page)) {
+                /*
+                 * hwpoisoned dirty swapcache pages are kept for killing
+                 * owner processes (which may be unknown at hwpoison time)
+                 */
                 ret = VM_FAULT_HWPOISON;
                 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
                 goto out_release;