diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 30 |
1 files changed, 13 insertions, 17 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1097d8098f8ce2..d0e57a3cda1899 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1042,6 +1042,19 @@ struct lruvec *mem_cgroup_lru_add_list(struct zone *zone, struct page *page, pc = lookup_page_cgroup(page); memcg = pc->mem_cgroup; + + /* + * Surreptitiously switch any uncharged page to root: + * an uncharged page off lru does nothing to secure + * its former mem_cgroup from sudden removal. + * + * Our caller holds lru_lock, and PageCgroupUsed is updated + * under page_cgroup lock: between them, they make all uses + * of pc->mem_cgroup safe. + */ + if (!PageCgroupUsed(pc) && memcg != root_mem_cgroup) + pc->mem_cgroup = memcg = root_mem_cgroup; + mz = page_cgroup_zoneinfo(memcg, page); /* compound_order() is stabilized through lru_lock */ MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); @@ -3029,23 +3042,6 @@ void mem_cgroup_uncharge_end(void) batch->memcg = NULL; } -/* - * A function for resetting pc->mem_cgroup for newly allocated pages. - * This function should be called if the newpage will be added to LRU - * before start accounting. - */ -void mem_cgroup_reset_owner(struct page *newpage) -{ - struct page_cgroup *pc; - - if (mem_cgroup_disabled()) - return; - - pc = lookup_page_cgroup(newpage); - VM_BUG_ON(PageCgroupUsed(pc)); - pc->mem_cgroup = root_mem_cgroup; -} - #ifdef CONFIG_SWAP /* * called after __delete_from_swap_cache() and drop "page" account. |