From: Qi Zheng Refactor the memcg_reparent_objcgs() to facilitate subsequent reparenting LRU folios here. Signed-off-by: Qi Zheng --- mm/memcontrol.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 930dacd6ce31a..3daa99a0c65fe 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -206,24 +206,41 @@ static struct obj_cgroup *obj_cgroup_alloc(void) return objcg; } -static void memcg_reparent_objcgs(struct mem_cgroup *memcg) +static inline void __memcg_reparent_objcgs(struct mem_cgroup *src, + struct mem_cgroup *dst) { struct obj_cgroup *objcg, *iter; - struct mem_cgroup *parent = parent_mem_cgroup(memcg); - - objcg = rcu_replace_pointer(memcg->objcg, NULL, true); - - spin_lock_irq(&objcg_lock); + objcg = rcu_replace_pointer(src->objcg, NULL, true); /* 1) Ready to reparent active objcg. */ - list_add(&objcg->list, &memcg->objcg_list); + list_add(&objcg->list, &src->objcg_list); /* 2) Reparent active objcg and already reparented objcgs to parent. */ - list_for_each_entry(iter, &memcg->objcg_list, list) - WRITE_ONCE(iter->memcg, parent); + list_for_each_entry(iter, &src->objcg_list, list) + WRITE_ONCE(iter->memcg, dst); /* 3) Move already reparented objcgs to the parent's list */ - list_splice(&memcg->objcg_list, &parent->objcg_list); + list_splice(&src->objcg_list, &dst->objcg_list); +} + +static inline void reparent_locks(struct mem_cgroup *src, struct mem_cgroup *dst) +{ + spin_lock_irq(&objcg_lock); +} +static inline void reparent_unlocks(struct mem_cgroup *src, struct mem_cgroup *dst) +{ spin_unlock_irq(&objcg_lock); +} + +static void memcg_reparent_objcgs(struct mem_cgroup *src) +{ + struct obj_cgroup *objcg = rcu_dereference_protected(src->objcg, true); + struct mem_cgroup *dst = parent_mem_cgroup(src); + + reparent_locks(src, dst); + + __memcg_reparent_objcgs(src, dst); + + reparent_unlocks(src, dst); percpu_ref_kill(&objcg->refcnt); } -- 2.20.1