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From: Ding Hui <dinghui@sangfor.com.cn>
To: akpm@linux-foundation.org, naoya.horiguchi@nec.com, osalvador@suse.de
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Ding Hui <dinghui@sangfor.com.cn>
Subject: [RFC PATCH] mm/page_alloc: fix counting of free pages after take off from buddy
Date: Wed, 21 Apr 2021 10:04:26 +0800	[thread overview]
Message-ID: <20210421020426.5914-1-dinghui@sangfor.com.cn> (raw)

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@sangfor.com.cn>
---
 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;
 		}
-- 
2.17.1


             reply	other threads:[~2021-04-21  2:13 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-21  2:04 Ding Hui [this message]
2021-04-28 14:54 ` [RFC PATCH] mm/page_alloc: fix counting of free pages after take off from buddy David Hildenbrand
2021-04-30  9:43   ` Ding Hui
2021-05-08  3:55     ` [PATCH v2] " Ding Hui
2021-05-25  8:32       ` HORIGUCHI NAOYA(堀口　直也)
2021-05-26  0:43         ` Ding Hui
2021-05-06  2:49   ` [RFC PATCH] " HORIGUCHI NAOYA(堀口　直也)
2021-05-06  4:01     ` Ding Hui
2021-05-06  7:30       ` HORIGUCHI NAOYA(堀口　直也)
2021-05-07  1:46         ` Ding Hui

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