From 465939a1fa283cf2a5194362c5accf4429c99c42 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 8 Jul 2013 16:00:38 -0700 Subject: [PATCH] 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 59927fb984d ("memcg: free mem_cgroup by RCU to fix oops"). Signed-off-by: Li Zefan Cc: Hugh Dickins Acked-by: Michal Hocko Acked-by: KAMEZAWA Hiroyuki Cc: Tejun Heo Cc: Glauber Costa Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 51 +++++-------------------------------------------- 1 file changed, 5 insertions(+), 46 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index fa521a2f4bf6..d12ca6f3c293 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -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 -- 2.30.2