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 <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Paul Menage <menage@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: David Rientjes <rientjes@google.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 128f45c..e8493fb 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -250,7 +250,7 @@
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 @@
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--;
