diff options
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 66 |
1 files changed, 40 insertions, 26 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3d4bb07c7679..f20a57b7faf2 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -500,6 +500,29 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) return (memcg == root_mem_cgroup); } +/* + * We restrict the id in the range of [1, 65535], so it can fit into + * an unsigned short. + */ +#define MEM_CGROUP_ID_MAX USHRT_MAX + +static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) +{ + /* + * The ID of the root cgroup is 0, but memcg treat 0 as an + * invalid ID, so we return (cgroup_id + 1). + */ + return memcg->css.cgroup->id + 1; +} + +static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) +{ + struct cgroup_subsys_state *css; + + css = css_from_id(id - 1, &mem_cgroup_subsys); + return mem_cgroup_from_css(css); +} + /* Writing them here to avoid exposing memcg's inner layout */ #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM) @@ -571,16 +594,11 @@ static void disarm_sock_keys(struct mem_cgroup *memcg) #ifdef CONFIG_MEMCG_KMEM /* * This will be the memcg's index in each cache's ->memcg_params->memcg_caches. - * There are two main reasons for not using the css_id for this: - * 1) this works better in sparse environments, where we have a lot of memcgs, - * but only a few kmem-limited. Or also, if we have, for instance, 200 - * memcgs, and none but the 200th is kmem-limited, we'd have to have a - * 200 entry array for that. - * - * 2) In order not to violate the cgroup API, we would like to do all memory - * allocation in ->create(). At that point, we haven't yet allocated the - * css_id. Having a separate index prevents us from messing with the cgroup - * core for this + * The main reason for not using cgroup id for this: + * this works better in sparse environments, where we have a lot of memcgs, + * but only a few kmem-limited. Or also, if we have, for instance, 200 + * memcgs, and none but the 200th is kmem-limited, we'd have to have a + * 200 entry array for that. * * The current size of the caches array is stored in * memcg_limited_groups_array_size. It will double each time we have to @@ -595,14 +613,14 @@ int memcg_limited_groups_array_size; * cgroups is a reasonable guess. In the future, it could be a parameter or * tunable, but that is strictly not necessary. * - * MAX_SIZE should be as large as the number of css_ids. Ideally, we could get + * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get * this constant directly from cgroup, but it is understandable that this is * better kept as an internal representation in cgroup.c. In any case, the - * css_id space is not getting any smaller, and we don't have to necessarily + * cgrp_id space is not getting any smaller, and we don't have to necessarily * increase ours as well if it increases. */ #define MEMCG_CACHES_MIN_SIZE 4 -#define MEMCG_CACHES_MAX_SIZE 65535 +#define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX /* * A lot of the calls to the cache allocation functions are expected to be @@ -1409,7 +1427,7 @@ bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, return true; if (!root_memcg->use_hierarchy || !memcg) return false; - return css_is_ancestor(&memcg->css, &root_memcg->css); + return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup); } static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, @@ -2827,15 +2845,10 @@ static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg, */ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) { - struct cgroup_subsys_state *css; - /* ID 0 is unused ID */ if (!id) return NULL; - css = css_lookup(&mem_cgroup_subsys, id); - if (!css) - return NULL; - return mem_cgroup_from_css(css); + return mem_cgroup_from_id(id); } struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) @@ -4344,7 +4357,7 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) * css_get() was called in uncharge(). */ if (do_swap_account && swapout && memcg) - swap_cgroup_record(ent, css_id(&memcg->css)); + swap_cgroup_record(ent, mem_cgroup_id(memcg)); } #endif @@ -4396,8 +4409,8 @@ static int mem_cgroup_move_swap_account(swp_entry_t entry, { unsigned short old_id, new_id; - old_id = css_id(&from->css); - new_id = css_id(&to->css); + old_id = mem_cgroup_id(from); + new_id = mem_cgroup_id(to); if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { mem_cgroup_swap_statistics(from, false); @@ -6165,7 +6178,6 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) size_t size = memcg_size(); mem_cgroup_remove_from_trees(memcg); - free_css_id(&mem_cgroup_subsys, &memcg->css); for_each_node(node) free_mem_cgroup_per_zone_info(memcg, node); @@ -6268,6 +6280,9 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css) struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css)); int error = 0; + if (css->cgroup->id > MEM_CGROUP_ID_MAX) + return -ENOSPC; + if (!parent) return 0; @@ -6539,7 +6554,7 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma, } /* There is a swap entry and a page doesn't exist or isn't charged */ if (ent.val && !ret && - css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) { + mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) { ret = MC_TARGET_SWAP; if (target) target->ent = ent; @@ -6959,7 +6974,6 @@ struct cgroup_subsys mem_cgroup_subsys = { .bind = mem_cgroup_bind, .base_cftypes = mem_cgroup_files, .early_init = 0, - .use_id = 1, }; #ifdef CONFIG_MEMCG_SWAP |