We should increase/decrease css->refcnt properly in charging/uncharging compound pages. Without this patch, a bug like below happens: 1. create a memcg directory. 2. run a program which uses enough memory to allocate them as transparent huge pages. 3. kill the program. 4. try to remove the directory, which will never finish. Signed-off-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b1ac9b1..b74bd83 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1650,8 +1650,9 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, } if (csize > page_size) refill_stock(mem, csize - page_size); + /* increase css->refcnt by the number of tail pages */ if (page_size != PAGE_SIZE) - __css_get(&mem->css, page_size); + __css_get(&mem->css, (page_size >> PAGE_SHIFT) - 1); done: return 0; nomem: @@ -2237,7 +2238,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) memcg_check_events(mem, page); /* at swapout, this memcg will be accessed to record to swap */ if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT) - css_put(&mem->css); + __css_put(&mem->css, page_size >> PAGE_SHIFT); return mem; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>