Commit 465939a1 authored by Li Zefan's avatar Li Zefan Committed by Linus Torvalds
Browse files

memcg: don't need to free memcg via RCU or workqueue

Now memcg has the same life cycle with its corresponding cgroup, and a
cgroup is freed via RCU and then mem_cgroup_css_free() will be called in
a work function, so we can simply call __mem_cgroup_free() in
mem_cgroup_css_free().

This actually reverts commit 59927fb9

 ("memcg: free mem_cgroup by RCU
to fix oops").
Signed-off-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Acked-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e0743e6b
......@@ -263,28 +263,10 @@ struct mem_cgroup {
/* vmpressure notifications */
struct vmpressure vmpressure;
union {
/*
* the counter to account for mem+swap usage.
*/
struct res_counter memsw;
/*
* rcu_freeing is used only when freeing struct mem_cgroup,
* so put it into a union to avoid wasting more memory.
* It must be disjoint from the css field. It could be
* in a union with the res field, but res plays a much
* larger part in mem_cgroup life than memsw, and might
* be of interest, even at time of free, when debugging.
* So share rcu_head with the less interesting memsw.
*/
struct rcu_head rcu_freeing;
/*
* We also need some space for a worker in deferred freeing.
* By the time we call it, rcu_freeing is no longer in use.
*/
struct work_struct work_freeing;
};
/*
* the counter to account for mem+swap usage.
*/
struct res_counter memsw;
/*
* the counter to account for kernel memory usage.
......@@ -6211,29 +6193,6 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
vfree(memcg);
}
/*
* Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU,
* but in process context. The work_freeing structure is overlaid
* on the rcu_freeing structure, which itself is overlaid on memsw.
*/
static void free_work(struct work_struct *work)
{
struct mem_cgroup *memcg;
memcg = container_of(work, struct mem_cgroup, work_freeing);
__mem_cgroup_free(memcg);
}
static void free_rcu(struct rcu_head *rcu_head)
{
struct mem_cgroup *memcg;
memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing);
INIT_WORK(&memcg->work_freeing, free_work);
schedule_work(&memcg->work_freeing);
}
/*
* Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
*/
......@@ -6383,7 +6342,7 @@ static void mem_cgroup_css_free(struct cgroup *cont)
struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
memcg_destroy_kmem(memcg);
call_rcu(&memcg->rcu_freeing, free_rcu);
__mem_cgroup_free(memcg);
}
#ifdef CONFIG_MMU
......
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