linux-kernel - [RFC][PATCH v1 10/11] mm: clear PageHWPoison in memory hotremove

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Date:   Fri,  9 Nov 2018 15:47:14 +0900
From:   Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Michal Hocko <mhocko@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        xishi.qiuxishi@...baba-inc.com,
        Laurent Dufour <ldufour@...ux.vnet.ibm.com>
Subject: [RFC][PATCH v1 10/11] mm: clear PageHWPoison in memory hotremove

One hopeful usecase of memory hotplug is to replace half-broken DIMMs
with new ones, so it makes sense to clear hwpoison info at the time of
memory hotremove.

I hope that this patch covers the topic discussed in
https://lkml.org/lkml/2018/1/17/1228

Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
---
 mm/page_alloc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git v4.19-mmotm-2018-10-30-16-08/mm/page_alloc.c v4.19-mmotm-2018-10-30-16-08_patched/mm/page_alloc.c
index 970d6ff..27826b3 100644
--- v4.19-mmotm-2018-10-30-16-08/mm/page_alloc.c
+++ v4.19-mmotm-2018-10-30-16-08_patched/mm/page_alloc.c
@@ -8139,8 +8139,9 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
 		 * The HWPoisoned page may be not in buddy system, and
 		 * page_count() is not 0.
 		 */
-		if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
+		if (unlikely(!PageBuddy(page) && TestClearPageHWPoison(page))) {
 			pfn++;
+			num_poisoned_pages_dec();
 			SetPageReserved(page);
 			continue;
 		}
-- 
2.7.0