Commit ab5196c2 authored by Michal Hocko's avatar Michal Hocko Committed by Tejun Heo
Browse files

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: default avatarMichal Hocko <mhocko@suse.cz>
Reviewed-by: default avatarGlauber Costa <glommer@parallels.com>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent b25ed609

mm/memcontrol.c

+6 −13
Original line number Diff line number Diff line
@@ -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)

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