[PATCH v2 2/5] memory-hotplug: update mce_bad_pages when removing the memory

[wency]

From: Wen Congyang <wency@xxxxxxxxxxxxxx>

When we hotremove a memory device, we will free the memory to store
struct page. If the page is hwpoisoned page, we should decrease
mce_bad_pages.

CC: David Rientjes <rientjes@xxxxxxxxxx>
CC: Jiang Liu <liuj97@xxxxxxxxx>
CC: Len Brown <len.brown@xxxxxxxxx>
CC: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
CC: Paul Mackerras <paulus@xxxxxxxxx>
CC: Christoph Lameter <cl@xxxxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
CC: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
---
 mm/sparse.c |   21 +++++++++++++++++++++
 1 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index fac95f2..24072e4 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -773,6 +773,23 @@ out:
 	return ret;
 }
 
+#ifdef CONFIG_MEMORY_FAILURE
+static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
+{
+	int i;
+
+	if (!memmap)
+		return;
+
+	for (i = 0; i < PAGES_PER_SECTION; i++) {
+		if (PageHWPoison(&memmap[i])) {
+			atomic_long_sub(1, &mce_bad_pages);
+			ClearPageHWPoison(&memmap[i]);
+		}
+	}
+}
+#endif
+
 void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
 {
 	struct page *memmap = NULL;
@@ -786,6 +803,10 @@ void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
 		ms->pageblock_flags = NULL;
 	}
 
+#ifdef CONFIG_MEMORY_FAILURE
+	clear_hwpoisoned_pages(memmap, PAGES_PER_SECTION);
+#endif
+
 	free_section_usemap(memmap, usemap);
 }
 #endif
-- 
1.7.1

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