From 6fb332fabd7288af9dbe7992394aa6ba97c1a537 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 21 Sep 2009 17:01:17 -0700 Subject: [PATCH] memory hotplug: exclude isolated page from pco page alloc Pages marked as isolated should not be allocated again. If such pages reside in pcp list, they can be allocated too, so there is a ping-pong memory offline frees some pages to pcp list and the pages get allocated and then memory offline frees them again, this loop will happen again and again. This should have no impact in normal code path, because in normal code path, pages in pcp list aren't isolated, and below loop will break in the first entry. Signed-off-by: Shaohua Li Cc: Mel Gorman Cc: Christoph Lameter Cc: Yakui Zhao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1a3a893ef50e..8a8302711725 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1143,10 +1143,20 @@ again: /* Allocate more to the pcp list if necessary */ if (unlikely(&page->lru == &pcp->list)) { + int get_one_page = 0; + pcp->count += rmqueue_bulk(zone, 0, pcp->batch, &pcp->list, migratetype, cold); - page = list_entry(pcp->list.next, struct page, lru); + list_for_each_entry(page, &pcp->list, lru) { + if (get_pageblock_migratetype(page) != + MIGRATE_ISOLATE) { + get_one_page = 1; + break; + } + } + if (!get_one_page) + goto failed; } list_del(&page->lru);