NR_FREE_PAGES will be wrong after offlining pages. We add/dec
NR_FREE_PAGES like this now:
1. move all pages in buddy system to MIGRATE_ISOLATE, and dec NR_FREE_PAGES
2. don't add NR_FREE_PAGES when it is freed and the migratetype is
MIGRATE_ISOLATE
3. dec NR_FREE_PAGES when offlining isolated pages.
4. add NR_FREE_PAGES when undoing isolate pages.
When we come to step 3, all pages are in MIGRATE_ISOLATE list, and
NR_FREE_PAGES are right. When we come to step4, all pages are not in
buddy system, so we don't change NR_FREE_PAGES in this step, but we change
NR_FREE_PAGES in step3. So NR_FREE_PAGES is wrong after offlining pages.
So there is no need to change NR_FREE_PAGES in step3.
This patch also fixs a problem in step2: if the migratetype is
MIGRATE_ISOLATE, we should not add NR_FRR_PAGES when we remove pages from
pcppages.
Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
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: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5b74de6..a7cd2d1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -667,11 +667,13 @@ static void free_pcppages_bulk(struct zone *zone, int count,
/* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
__free_one_page(page, zone, 0, mt);
trace_mm_page_pcpu_drain(page, 0, mt);
- if (is_migrate_cma(mt))
- __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
+ if (likely(mt != MIGRATE_ISOLATE)) {
+ __mod_zone_page_state(zone, NR_FREE_PAGES, 1);
+ if (is_migrate_cma(mt))
+ __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, 1);
+ }
} while (--to_free && --batch_free && !list_empty(list));
}
- __mod_zone_page_state(zone, NR_FREE_PAGES, count);
spin_unlock(&zone->lock);
}
@@ -5987,8 +5989,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
list_del(&page->lru);
rmv_page_order(page);
zone->free_area[order].nr_free--;
- __mod_zone_page_state(zone, NR_FREE_PAGES,
- - (1UL << order));
for (i = 0; i < (1 << order); i++)
SetPageReserved((page+i));
pfn += (1 << order);
--
1.8.0
--
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