On 2021/4/28 22:54, David Hildenbrand wrote:
On 21.04.21 04:04, Ding Hui wrote:
Recently we found there is a lot MemFree left in /proc/meminfo after
do a lot of pages soft offline.
I think it's incorrect since NR_FREE_PAGES should not contain HWPoison
pages.
After take_page_off_buddy, the page is no longer belong to buddy
allocator, and will not be used any more, but we maybe missed accounting
NR_FREE_PAGES in this situation.
Signed-off-by: Ding Hui <dinghui@xxxxxxxxxxxxxx>
---
mm/page_alloc.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cfc72873961d..8d65b62784d8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8947,6 +8947,7 @@ bool take_page_off_buddy(struct page *page)
del_page_from_free_list(page_head, zone, page_order);
break_down_buddy_pages(zone, page_head, page, 0,
page_order, migratetype);
+ __mod_zone_page_state(zone, NR_FREE_PAGES, -1);
ret = true;
break;
}
Should this use __mod_zone_freepage_state() instead?
Yes, you're right.
I'll use it in v2.
--
Thanks,
- Ding Hui
