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 <[email protected]> Cc: David Rientjes <[email protected]> Cc: Jiang Liu <[email protected]> Cc: Len Brown <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Christoph Lameter <[email protected]> Cc: Minchan Kim <[email protected]> Cc: KOSAKI Motohiro <[email protected]> Cc: Yasuaki Ishimatsu <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Mel Gorman <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
