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mm: memcontrol: give the kmem states more descriptive names

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On any given memcg, the kmem accounting feature has three separate
states: not initialized, structures allocated, and actively accounting
slab memory.  These are represented through a combination of the
kmem_acct_activated and kmem_acct_active flags, which is confusing.

Convert to a kmem_state enum with the states NONE, ALLOCATED, and
ONLINE.  Then rename the functions to modify the state accordingly.
This follows the nomenclature of css object states more closely.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Johannes Weiner 2016-01-20 15:02:24 -08:00 committed by Linus Torvalds
parent b15aac110a
commit 567e9ab2e6
4 changed files with 38 additions and 35 deletions
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15
include/linux/memcontrol.h
View file

@ -152,6 +152,12 @@ struct mem_cgroup_thresholds {
struct mem_cgroup_threshold_ary *spare;
};
enum memcg_kmem_state {
KMEM_NONE,
KMEM_ALLOCATED,
KMEM_ONLINE,
};
/*
* The memory controller data structure. The memory controller controls both
* page cache and RSS per cgroup. We would eventually like to provide
@ -233,8 +239,7 @@ struct mem_cgroup {
#if defined(CONFIG_MEMCG_KMEM)
/* Index in the kmem_cache->memcg_params.memcg_caches array */
int kmemcg_id;
bool kmem_acct_activated;
bool kmem_acct_active;
enum memcg_kmem_state kmem_state;
#endif
int last_scanned_node;
@ -750,9 +755,9 @@ static inline bool memcg_kmem_enabled(void)
return static_branch_unlikely(&memcg_kmem_enabled_key);
}
static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
static inline bool memcg_kmem_online(struct mem_cgroup *memcg)
{
return memcg->kmem_acct_active;
return memcg->kmem_state == KMEM_ONLINE;
}
/*
@ -850,7 +855,7 @@ static inline bool memcg_kmem_enabled(void)
return false;
}
static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
static inline bool memcg_kmem_online(struct mem_cgroup *memcg)
{
return false;
}

52
mm/memcontrol.c
View file

@ -2378,7 +2378,7 @@ int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
struct page_counter *counter;
int ret;
if (!memcg_kmem_is_active(memcg))
if (!memcg_kmem_online(memcg))
return 0;
if (!page_counter_try_charge(&memcg->kmem, nr_pages, &counter))
@ -2861,14 +2861,13 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
}
#ifdef CONFIG_MEMCG_KMEM
static int memcg_activate_kmem(struct mem_cgroup *memcg)
static int memcg_online_kmem(struct mem_cgroup *memcg)
{
int err = 0;
int memcg_id;
BUG_ON(memcg->kmemcg_id >= 0);
BUG_ON(memcg->kmem_acct_activated);
BUG_ON(memcg->kmem_acct_active);
BUG_ON(memcg->kmem_state);
/*
* For simplicity, we won't allow this to be disabled. It also can't
@ -2898,14 +2897,13 @@ static int memcg_activate_kmem(struct mem_cgroup *memcg)
static_branch_inc(&memcg_kmem_enabled_key);
/*
* A memory cgroup is considered kmem-active as soon as it gets
* A memory cgroup is considered kmem-online as soon as it gets
* kmemcg_id. Setting the id after enabling static branching will
* guarantee no one starts accounting before all call sites are
* patched.
*/
memcg->kmemcg_id = memcg_id;
memcg->kmem_acct_activated = true;
memcg->kmem_acct_active = true;
memcg->kmem_state = KMEM_ONLINE;
out:
return err;
}
@ -2917,8 +2915,8 @@ static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
mutex_lock(&memcg_limit_mutex);
/* Top-level cgroup doesn't propagate from root */
if (!memcg_kmem_is_active(memcg)) {
ret = memcg_activate_kmem(memcg);
if (!memcg_kmem_online(memcg)) {
ret = memcg_online_kmem(memcg);
if (ret)
goto out;
}
@ -2938,11 +2936,12 @@ static int memcg_propagate_kmem(struct mem_cgroup *memcg)
mutex_lock(&memcg_limit_mutex);
/*
* If the parent cgroup is not kmem-active now, it cannot be activated
* after this point, because it has at least one child already.
* If the parent cgroup is not kmem-online now, it cannot be
* onlined after this point, because it has at least one child
* already.
*/
if (memcg_kmem_is_active(parent))
ret = memcg_activate_kmem(memcg);
if (memcg_kmem_online(parent))
ret = memcg_online_kmem(memcg);
mutex_unlock(&memcg_limit_mutex);
return ret;
}
@ -3590,22 +3589,21 @@ static int memcg_init_kmem(struct mem_cgroup *memcg)
return tcp_init_cgroup(memcg);
}
static void memcg_deactivate_kmem(struct mem_cgroup *memcg)
static void memcg_offline_kmem(struct mem_cgroup *memcg)
{
struct cgroup_subsys_state *css;
struct mem_cgroup *parent, *child;
int kmemcg_id;
if (!memcg->kmem_acct_active)
if (memcg->kmem_state != KMEM_ONLINE)
return;
/*
* Clear the 'active' flag before clearing memcg_caches arrays entries.
* Since we take the slab_mutex in memcg_deactivate_kmem_caches(), it
* guarantees no cache will be created for this cgroup after we are
* done (see memcg_create_kmem_cache()).
* Clear the online state before clearing memcg_caches array
* entries. The slab_mutex in memcg_deactivate_kmem_caches()
* guarantees that no cache will be created for this cgroup
* after we are done (see memcg_create_kmem_cache()).
*/
memcg->kmem_acct_active = false;
memcg->kmem_state = KMEM_ALLOCATED;
memcg_deactivate_kmem_caches(memcg);
@ -3636,9 +3634,9 @@ static void memcg_deactivate_kmem(struct mem_cgroup *memcg)
memcg_free_cache_id(kmemcg_id);
}
static void memcg_destroy_kmem(struct mem_cgroup *memcg)
static void memcg_free_kmem(struct mem_cgroup *memcg)
{
if (memcg->kmem_acct_activated) {
if (memcg->kmem_state == KMEM_ALLOCATED) {
memcg_destroy_kmem_caches(memcg);
static_branch_dec(&memcg_kmem_enabled_key);
WARN_ON(page_counter_read(&memcg->kmem));
@ -3651,11 +3649,11 @@ static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
return 0;
}
static void memcg_deactivate_kmem(struct mem_cgroup *memcg)
static void memcg_offline_kmem(struct mem_cgroup *memcg)
{
}
static void memcg_destroy_kmem(struct mem_cgroup *memcg)
static void memcg_free_kmem(struct mem_cgroup *memcg)
{
}
#endif
@ -4308,7 +4306,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
vmpressure_cleanup(&memcg->vmpressure);
memcg_deactivate_kmem(memcg);
memcg_offline_kmem(memcg);
wb_memcg_offline(memcg);
}
@ -4324,7 +4322,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
memcg_destroy_kmem(memcg);
memcg_free_kmem(memcg);
#ifdef CONFIG_INET
if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
static_branch_dec(&memcg_sockets_enabled_key);

4
mm/slab_common.c
View file

@ -503,10 +503,10 @@ void memcg_create_kmem_cache(struct mem_cgroup *memcg,
mutex_lock(&slab_mutex);
/*
* The memory cgroup could have been deactivated while the cache
* The memory cgroup could have been offlined while the cache
* creation work was pending.
*/
if (!memcg_kmem_is_active(memcg))
if (!memcg_kmem_online(memcg))
goto out_unlock;
idx = memcg_cache_id(memcg);

2
mm/vmscan.c
View file

@ -411,7 +411,7 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
struct shrinker *shrinker;
unsigned long freed = 0;
if (memcg && !memcg_kmem_is_active(memcg))
if (memcg && !memcg_kmem_online(memcg))
return 0;
if (nr_scanned == 0)