bugfix for memory cgroup controller: avoid !PageLRU page in mem_cgroup_isolate_pages
[linux-2.6.git] / mm / memcontrol.c
index 128f45c..e8493fb 100644 (file)
@@ -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--;