On 2021/5/25 16:32, HORIGUCHI NAOYA(堀口 直也) wrote:
On Sat, May 08, 2021 at 11:55:33AM +0800, 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.
For offline free pages, after a successful call take_page_off_buddy(), the
page is no longer belong to buddy allocator, and will not be used any more,
but we missed accounting NR_FREE_PAGES in this situation.
Do update like rmqueue() does.
Signed-off-by: Ding Hui <dinghui@xxxxxxxxxxxxxx>
---
V2:
use __mod_zone_freepage_state instead of __mod_zone_page_state
mm/page_alloc.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cfc72873961d..e124a615303b 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_freepage_state(zone, -1, migratetype);
Page offline code (see set_migratetype_isolate()) seems to handle
NR_FREE_PAGES counter in its own way, so I think that it's more correct to
call __mod_zone_freepage_state() only when is_migrate_isolate(migratetype))
is false.
Otherwise, the patch looks good to me.
Thanks for reply and suggestion, I'll send v3 patch later.
ret = true;
break;
}
--
2.17.1
--
Thanks,
- Ding Hui
