From ff7283fa3a66823933991ad55a558a3a01d5ab27 Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Thu, 7 Feb 2008 00:14:11 -0800 Subject: bugfix for memory cgroup controller: avoid !PageLRU page in mem_cgroup_isolate_pages This patch makes mem_cgroup_isolate_pages() to be - ignore !PageLRU pages. - fixes the bug that isolation makes no progress if page_zone(page) != zone page once find. (just increment scan in this case.) kswapd and memory migration removes a page from list when it handles a page for reclaiming/migration. Because __isolate_lru_page() doesn't moves page !PageLRU pages, it will be safe to avoid touching !PageLRU() page and its page_cgroup. Signed-off-by: KAMEZAWA Hiroyuki Cc: Balbir Singh Cc: Pavel Emelianov Cc: Paul Menage Cc: Peter Zijlstra Cc: "Eric W. Biederman" Cc: Nick Piggin Cc: Kirill Korotaev Cc: Herbert Poetzl Cc: David Rientjes Cc: Vaidyanathan Srinivasan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 128f45c16fa6..e8493fb2d69e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -250,7 +250,7 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, unsigned long scan; LIST_HEAD(pc_list); struct list_head *src; - struct page_cgroup *pc; + struct page_cgroup *pc, *tmp; if (active) src = &mem_cont->active_list; @@ -258,11 +258,18 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, src = &mem_cont->inactive_list; spin_lock(&mem_cont->lru_lock); - for (scan = 0; scan < nr_to_scan && !list_empty(src); scan++) { - pc = list_entry(src->prev, struct page_cgroup, lru); + scan = 0; + list_for_each_entry_safe_reverse(pc, tmp, src, lru) { + if (scan++ > nr_to_scan) + break; page = pc->page; VM_BUG_ON(!pc); + if (unlikely(!PageLRU(page))) { + scan--; + continue; + } + if (PageActive(page) && !active) { __mem_cgroup_move_lists(pc, true); scan--; -- cgit v1.2.3