From f7195656c3f6fc0498ad454175126160077384de Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Sat, 21 Jul 2012 10:54:10 +1000 Subject: [PATCH] mm: clean up __count_immobile_pages() The __count_immobile_pages() naming is rather awkward. Choose a more clear name and add a comment. Signed-off-by: Minchan Kim Cc: Andrea Arcangeli Cc: Mel Gorman Cc: Michal Hocko Acked-by: KAMEZAWA Hiroyuki Cc: Bartlomiej Zolnierkiewicz Signed-off-by: Andrew Morton --- mm/page_alloc.c | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 710add6f17b3..ac65b4d42937 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5470,26 +5470,28 @@ void set_pageblock_flags_group(struct page *page, unsigned long flags, } /* - * This is designed as sub function...plz see page_isolation.c also. - * set/clear page block's type to be ISOLATE. - * page allocater never alloc memory from ISOLATE block. + * This function checks whether pageblock includes unmovable pages or not. + * If @count is not zero, it is okay to include less @count unmovable pages + * + * PageLRU check wihtout isolation or lru_lock could race so that + * MIGRATE_MOVABLE block might include unmovable pages. It means you can't + * expect this function should be exact. */ - -static int -__count_immobile_pages(struct zone *zone, struct page *page, int count) +static bool +__has_unmovable_pages(struct zone *zone, struct page *page, int count) { unsigned long pfn, iter, found; int mt; /* * For avoiding noise data, lru_add_drain_all() should be called - * If ZONE_MOVABLE, the zone never contains immobile pages + * If ZONE_MOVABLE, the zone never contains unmovable pages */ if (zone_idx(zone) == ZONE_MOVABLE) - return true; + return false; mt = get_pageblock_migratetype(page); if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt)) - return true; + return false; pfn = page_to_pfn(page); for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) { @@ -5527,9 +5529,9 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count) * page at boot. */ if (found > count) - return false; + return true; } - return true; + return false; } bool is_pageblock_removable_nolock(struct page *page) @@ -5553,7 +5555,7 @@ bool is_pageblock_removable_nolock(struct page *page) zone->zone_start_pfn + zone->spanned_pages <= pfn) return false; - return __count_immobile_pages(zone, page, 0); + return !__has_unmovable_pages(zone, page, 0); } int set_migratetype_isolate(struct page *page) @@ -5592,12 +5594,12 @@ int set_migratetype_isolate(struct page *page) * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. * We just check MOVABLE pages. */ - if (__count_immobile_pages(zone, page, arg.pages_found)) + if (!__has_unmovable_pages(zone, page, arg.pages_found)) ret = 0; - /* - * immobile means "not-on-lru" paes. If immobile is larger than - * removable-by-driver pages reported by notifier, we'll fail. + * Unmovable means "not-on-lru" pages. If Unmovable pages are + * larger than removable-by-driver pages reported by notifier, + * we'll fail. */ out: -- 2.39.5