diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 20e1d90b3363a6e59191e48fe1660af166732723..886e2224c5fdde439cb99da510159065e545b796 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -149,6 +149,10 @@ struct mem_cgroup { * reclaimed from. Protected by cgroup_lock() */ struct mem_cgroup *last_scanned_child; + /* + * Should the accounting and control be hierarchical, per subtree? + */ + bool use_hierarchy; int obsolete; atomic_t refcnt; @@ -1543,6 +1547,44 @@ int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) } +static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) +{ + return mem_cgroup_from_cont(cont)->use_hierarchy; +} + +static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, + u64 val) +{ + int retval = 0; + struct mem_cgroup *mem = mem_cgroup_from_cont(cont); + struct cgroup *parent = cont->parent; + struct mem_cgroup *parent_mem = NULL; + + if (parent) + parent_mem = mem_cgroup_from_cont(parent); + + cgroup_lock(); + /* + * If parent's use_hiearchy is set, we can't make any modifications + * in the child subtrees. If it is unset, then the change can + * occur, provided the current cgroup has no children. + * + * For the root cgroup, parent_mem is NULL, we allow value to be + * set if there are no children. + */ + if ((!parent_mem || !parent_mem->use_hierarchy) && + (val == 1 || val == 0)) { + if (list_empty(&cont->children)) + mem->use_hierarchy = val; + else + retval = -EBUSY; + } else + retval = -EINVAL; + cgroup_unlock(); + + return retval; +} + static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) { struct mem_cgroup *mem = mem_cgroup_from_cont(cont); @@ -1706,6 +1748,11 @@ static struct cftype mem_cgroup_files[] = { .name = "force_empty", .trigger = mem_cgroup_force_empty_write, }, + { + .name = "use_hierarchy", + .write_u64 = mem_cgroup_hierarchy_write, + .read_u64 = mem_cgroup_hierarchy_read, + }, }; #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP @@ -1881,12 +1928,18 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) if (cont->parent == NULL) { enable_swap_cgroup(); parent = NULL; - } else + } else { parent = mem_cgroup_from_cont(cont->parent); + mem->use_hierarchy = parent->use_hierarchy; + } - res_counter_init(&mem->res, parent ? &parent->res : NULL); - res_counter_init(&mem->memsw, parent ? &parent->memsw : NULL); - + if (parent && parent->use_hierarchy) { + res_counter_init(&mem->res, &parent->res); + res_counter_init(&mem->memsw, &parent->memsw); + } else { + res_counter_init(&mem->res, NULL); + res_counter_init(&mem->memsw, NULL); + } mem->last_scanned_child = NULL;