The patch titled
Subject: slab: link memcg caches of the same kind into a list
has been added to the -mm tree. Its filename is
slab-link-memcg-caches-of-the-same-kind-into-a-list.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/slab-link-memcg-caches-of-the-same-kind-into-a-list.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/slab-link-memcg-caches-of-the-same-kind-into-a-list.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Subject: slab: link memcg caches of the same kind into a list
Sometimes, we need to iterate over all memcg copies of a particular root
kmem cache. Currently, we use memcg_cache_params->memcg_caches array for
that, because it contains all existing memcg caches.
However, it's a bad practice to keep all caches, including those that
belong to offline cgroups, in this array, because it will be growing
beyond any bounds then. I'm going to wipe away dead caches from it to
save space. To still be able to perform iterations over all memcg caches
of the same kind, let us link them into a list.
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/slab.h | 4 ++++
mm/slab.c | 13 +++++--------
mm/slab.h | 17 +++++++++++++++++
mm/slab_common.c | 21 ++++++++++-----------
mm/slub.c | 19 +++++--------------
5 files changed, 41 insertions(+), 33 deletions(-)
diff -puN include/linux/slab.h~slab-link-memcg-caches-of-the-same-kind-into-a-list include/linux/slab.h
--- a/include/linux/slab.h~slab-link-memcg-caches-of-the-same-kind-into-a-list
+++ a/include/linux/slab.h
@@ -491,9 +491,13 @@ struct memcg_cache_array {
*
* @memcg: pointer to the memcg this cache belongs to
* @root_cache: pointer to the global, root cache, this cache was derived from
+ *
+ * Both root and child caches of the same kind are linked into a list chained
+ * through @list.
*/
struct memcg_cache_params {
bool is_root_cache;
+ struct list_head list;
union {
struct memcg_cache_array __rcu *memcg_caches;
struct {
diff -puN mm/slab.c~slab-link-memcg-caches-of-the-same-kind-into-a-list mm/slab.c
--- a/mm/slab.c~slab-link-memcg-caches-of-the-same-kind-into-a-list
+++ a/mm/slab.c
@@ -3708,8 +3708,7 @@ static int do_tune_cpucache(struct kmem_
int batchcount, int shared, gfp_t gfp)
{
int ret;
- struct kmem_cache *c = NULL;
- int i = 0;
+ struct kmem_cache *c;
ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
@@ -3719,12 +3718,10 @@ static int do_tune_cpucache(struct kmem_
if ((ret < 0) || !is_root_cache(cachep))
return ret;
- VM_BUG_ON(!mutex_is_locked(&slab_mutex));
- for_each_memcg_cache_index(i) {
- c = cache_from_memcg_idx(cachep, i);
- if (c)
- /* return value determined by the parent cache only */
- __do_tune_cpucache(c, limit, batchcount, shared, gfp);
+ lockdep_assert_held(&slab_mutex);
+ for_each_memcg_cache(c, cachep) {
+ /* return value determined by the root cache only */
+ __do_tune_cpucache(c, limit, batchcount, shared, gfp);
}
return ret;
diff -puN mm/slab.h~slab-link-memcg-caches-of-the-same-kind-into-a-list mm/slab.h
--- a/mm/slab.h~slab-link-memcg-caches-of-the-same-kind-into-a-list
+++ a/mm/slab.h
@@ -163,6 +163,18 @@ ssize_t slabinfo_write(struct file *file
size_t count, loff_t *ppos);
#ifdef CONFIG_MEMCG_KMEM
+/*
+ * Iterate over all memcg caches of the given root cache. The caller must hold
+ * slab_mutex.
+ */
+#define for_each_memcg_cache(iter, root) \
+ list_for_each_entry(iter, &(root)->memcg_params.list, \
+ memcg_params.list)
+
+#define for_each_memcg_cache_safe(iter, tmp, root) \
+ list_for_each_entry_safe(iter, tmp, &(root)->memcg_params.list, \
+ memcg_params.list)
+
static inline bool is_root_cache(struct kmem_cache *s)
{
return s->memcg_params.is_root_cache;
@@ -241,6 +253,11 @@ extern void slab_init_memcg_params(struc
#else /* !CONFIG_MEMCG_KMEM */
+#define for_each_memcg_cache(iter, root) \
+ for (iter = NULL, (root); 0; )
+#define for_each_memcg_cache_safe(iter, tmp, root) \
+ for (iter = NULL, tmp = NULL, (root); 0; )
+
static inline bool is_root_cache(struct kmem_cache *s)
{
return true;
diff -puN mm/slab_common.c~slab-link-memcg-caches-of-the-same-kind-into-a-list mm/slab_common.c
--- a/mm/slab_common.c~slab-link-memcg-caches-of-the-same-kind-into-a-list
+++ a/mm/slab_common.c
@@ -109,6 +109,7 @@ static inline int kmem_cache_sanity_chec
void slab_init_memcg_params(struct kmem_cache *s)
{
s->memcg_params.is_root_cache = true;
+ INIT_LIST_HEAD(&s->memcg_params.list);
RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
}
@@ -448,6 +449,7 @@ static int do_kmem_cache_shutdown(struct
lockdep_is_held(&slab_mutex));
BUG_ON(arr->entries[idx] != s);
arr->entries[idx] = NULL;
+ list_del(&s->memcg_params.list);
}
#endif
list_move(&s->list, release);
@@ -528,6 +530,8 @@ void memcg_create_kmem_cache(struct mem_
goto out_unlock;
}
+ list_add(&s->memcg_params.list, &root_cache->memcg_params.list);
+
/*
* Since readers won't lock (see cache_from_memcg_idx()), we need a
* barrier here to ensure nobody will see the kmem_cache partially
@@ -580,11 +584,13 @@ void slab_kmem_cache_release(struct kmem
void kmem_cache_destroy(struct kmem_cache *s)
{
- int i;
+ struct kmem_cache *c, *c2;
LIST_HEAD(release);
bool need_rcu_barrier = false;
bool busy = false;
+ BUG_ON(!is_root_cache(s));
+
get_online_cpus();
get_online_mems();
@@ -594,10 +600,8 @@ void kmem_cache_destroy(struct kmem_cach
if (s->refcount)
goto out_unlock;
- for_each_memcg_cache_index(i) {
- struct kmem_cache *c = cache_from_memcg_idx(s, i);
-
- if (c && do_kmem_cache_shutdown(c, &release, &need_rcu_barrier))
+ for_each_memcg_cache_safe(c, c2, s) {
+ if (do_kmem_cache_shutdown(c, &release, &need_rcu_barrier))
busy = true;
}
@@ -931,16 +935,11 @@ memcg_accumulate_slabinfo(struct kmem_ca
{
struct kmem_cache *c;
struct slabinfo sinfo;
- int i;
if (!is_root_cache(s))
return;
- for_each_memcg_cache_index(i) {
- c = cache_from_memcg_idx(s, i);
- if (!c)
- continue;
-
+ for_each_memcg_cache(c, s) {
memset(&sinfo, 0, sizeof(sinfo));
get_slabinfo(c, &sinfo);
diff -puN mm/slub.c~slab-link-memcg-caches-of-the-same-kind-into-a-list mm/slub.c
--- a/mm/slub.c~slab-link-memcg-caches-of-the-same-kind-into-a-list
+++ a/mm/slub.c
@@ -3636,13 +3636,10 @@ struct kmem_cache *
__kmem_cache_alias(const char *name, size_t size, size_t align,
unsigned long flags, void (*ctor)(void *))
{
- struct kmem_cache *s;
+ struct kmem_cache *s, *c;
s = find_mergeable(size, align, flags, name, ctor);
if (s) {
- int i;
- struct kmem_cache *c;
-
s->refcount++;
/*
@@ -3652,10 +3649,7 @@ __kmem_cache_alias(const char *name, siz
s->object_size = max(s->object_size, (int)size);
s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
- for_each_memcg_cache_index(i) {
- c = cache_from_memcg_idx(s, i);
- if (!c)
- continue;
+ for_each_memcg_cache(c, s) {
c->object_size = s->object_size;
c->inuse = max_t(int, c->inuse,
ALIGN(size, sizeof(void *)));
@@ -4921,7 +4915,7 @@ static ssize_t slab_attr_store(struct ko
err = attribute->store(s, buf, len);
#ifdef CONFIG_MEMCG_KMEM
if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
- int i;
+ struct kmem_cache *c;
mutex_lock(&slab_mutex);
if (s->max_attr_size < len)
@@ -4944,11 +4938,8 @@ static ssize_t slab_attr_store(struct ko
* directly either failed or succeeded, in which case we loop
* through the descendants with best-effort propagation.
*/
- for_each_memcg_cache_index(i) {
- struct kmem_cache *c = cache_from_memcg_idx(s, i);
- if (c)
- attribute->store(c, buf, len);
- }
+ for_each_memcg_cache(c, s)
+ attribute->store(c, buf, len);
mutex_unlock(&slab_mutex);
}
#endif
_
Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are
mm-vmscan-fix-highidx-argument-type.patch
memcg-zap-__memcg_chargeuncharge_slab.patch
memcg-zap-memcg_name-argument-of-memcg_create_kmem_cache.patch
memcg-zap-memcg_slab_caches-and-memcg_slab_mutex.patch
swap-remove-unused-mem_cgroup_uncharge_swapcache-declaration.patch
mm-memcontrol-track-move_lock-state-internally.patch
mm-vmscan-wake-up-all-pfmemalloc-throttled-processes-at-once.patch
list_lru-introduce-list_lru_shrink_countwalk.patch
fs-consolidate-nrfree_cached_objects-args-in-shrink_control.patch
vmscan-per-memory-cgroup-slab-shrinkers.patch
memcg-rename-some-cache-id-related-variables.patch
memcg-add-rwsem-to-synchronize-against-memcg_caches-arrays-relocation.patch
list_lru-get-rid-of-active_nodes.patch
list_lru-organize-all-list_lrus-to-list.patch
list_lru-introduce-per-memcg-lists.patch
fs-make-shrinker-memcg-aware.patch
vmscan-force-scan-offline-memory-cgroups.patch
vmscan-force-scan-offline-memory-cgroups-fix.patch
mm-page_counter-pull-1-handling-out-of-page_counter_memparse.patch
mm-memcontrol-default-hierarchy-interface-for-memory.patch
mm-memcontrol-fold-move_anon-and-move_file.patch
mm-memcontrol-fold-move_anon-and-move_file-fix.patch
mm-memcontrol-remove-unnecessary-soft-limit-tree-node-test.patch
mm-memcontrol-consolidate-memory-controller-initialization.patch
mm-memcontrol-consolidate-swap-controller-code.patch
fs-shrinker-always-scan-at-least-one-object-of-each-type.patch
fs-shrinker-always-scan-at-least-one-object-of-each-type-fix.patch
mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated.patch
mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated-fix.patch
slab-embed-memcg_cache_params-to-kmem_cache.patch
slab-link-memcg-caches-of-the-same-kind-into-a-list.patch
cgroup-release-css-id-after-css_free.patch
slab-use-css-id-for-naming-per-memcg-caches.patch
memcg-free-memcg_caches-slot-on-css-offline.patch
list_lru-add-helpers-to-isolate-items.patch
memcg-reparent-list_lrus-and-free-kmemcg_id-on-css-offline.patch
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