From ab5196c202c60f84c7a74975742806aad242d9e3 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Fri, 26 Oct 2012 13:37:32 +0200 Subject: [PATCH] memcg: make mem_cgroup_reparent_charges non failing Now that pre_destroy callbacks are called from the context where neither any task can attach the group nor any children group can be added there is no other way to fail from mem_cgroup_pre_destroy. mem_cgroup_pre_destroy doesn't have to take a reference to memcg's css because all css' are marked dead already. tj: Remove now unused local variable @cgrp from mem_cgroup_reparent_charges(). Signed-off-by: Michal Hocko Reviewed-by: Glauber Costa Acked-by: KAMEZAWA Hiroyuki Signed-off-by: Tejun Heo --- mm/memcontrol.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 930edfaa5187..6678f991c6c6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3740,14 +3740,11 @@ static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg, * * Caller is responsible for holding css reference on the memcg. */ -static int mem_cgroup_reparent_charges(struct mem_cgroup *memcg) +static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg) { - struct cgroup *cgrp = memcg->css.cgroup; int node, zid; do { - if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) - return -EBUSY; /* This is for making all *used* pages to be on LRU. */ lru_add_drain_all(); drain_all_stock_sync(memcg); @@ -3773,8 +3770,6 @@ static int mem_cgroup_reparent_charges(struct mem_cgroup *memcg) * charge before adding to the LRU. */ } while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0); - - return 0; } /* @@ -3811,7 +3806,9 @@ static int mem_cgroup_force_empty(struct mem_cgroup *memcg) } lru_add_drain(); - return mem_cgroup_reparent_charges(memcg); + mem_cgroup_reparent_charges(memcg); + + return 0; } static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) @@ -5008,13 +5005,9 @@ free_out: static int mem_cgroup_pre_destroy(struct cgroup *cont) { struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); - int ret; - css_get(&memcg->css); - ret = mem_cgroup_reparent_charges(memcg); - css_put(&memcg->css); - - return ret; + mem_cgroup_reparent_charges(memcg); + return 0; } static void mem_cgroup_destroy(struct cgroup *cont)