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authorRoman Gushchin <guro@fb.com>2020-08-06 23:21:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 11:33:25 -0700
commit10befea91b61c4e2c2d1df06a2e978d182fcf792 (patch)
treecc5c9a0e4d351194ccde996f5455248f45b5d56c /mm/slab_common.c
parent15999eef7f25e2ea6a1c33f026166f472c5714e9 (diff)
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mm: memcg/slab: use a single set of kmem_caches for all allocations
Instead of having two sets of kmem_caches: one for system-wide and non-accounted allocations and the second one shared by all accounted allocations, we can use just one. The idea is simple: space for obj_cgroup metadata can be allocated on demand and filled only for accounted allocations. It allows to remove a bunch of code which is required to handle kmem_cache clones for accounted allocations. There is no more need to create them, accumulate statistics, propagate attributes, etc. It's a quite significant simplification. Also, because the total number of slab_caches is reduced almost twice (not all kmem_caches have a memcg clone), some additional memory savings are expected. On my devvm it additionally saves about 3.5% of slab memory. [guro@fb.com: fix build on MIPS] Link: http://lkml.kernel.org/r/20200717214810.3733082-1-guro@fb.com Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Shakeel Butt <shakeelb@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Naresh Kamboju <naresh.kamboju@linaro.org> Link: http://lkml.kernel.org/r/20200623174037.3951353-18-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r--mm/slab_common.c230
1 files changed, 5 insertions, 225 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index ad67a03c592a..a513f3237155 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -130,36 +130,6 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
return i;
}
-#ifdef CONFIG_MEMCG_KMEM
-static void memcg_kmem_cache_create_func(struct work_struct *work)
-{
- struct kmem_cache *cachep = container_of(work, struct kmem_cache,
- memcg_params.work);
- memcg_create_kmem_cache(cachep);
-}
-
-void slab_init_memcg_params(struct kmem_cache *s)
-{
- s->memcg_params.root_cache = NULL;
- s->memcg_params.memcg_cache = NULL;
- INIT_WORK(&s->memcg_params.work, memcg_kmem_cache_create_func);
-}
-
-static void init_memcg_params(struct kmem_cache *s,
- struct kmem_cache *root_cache)
-{
- if (root_cache)
- s->memcg_params.root_cache = root_cache;
- else
- slab_init_memcg_params(s);
-}
-#else
-static inline void init_memcg_params(struct kmem_cache *s,
- struct kmem_cache *root_cache)
-{
-}
-#endif /* CONFIG_MEMCG_KMEM */
-
/*
* Figure out what the alignment of the objects will be given a set of
* flags, a user specified alignment and the size of the objects.
@@ -197,9 +167,6 @@ int slab_unmergeable(struct kmem_cache *s)
if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
return 1;
- if (!is_root_cache(s))
- return 1;
-
if (s->ctor)
return 1;
@@ -286,7 +253,6 @@ static struct kmem_cache *create_cache(const char *name,
s->useroffset = useroffset;
s->usersize = usersize;
- init_memcg_params(s, root_cache);
err = __kmem_cache_create(s, flags);
if (err)
goto out_free_cache;
@@ -344,7 +310,6 @@ kmem_cache_create_usercopy(const char *name,
get_online_cpus();
get_online_mems();
- memcg_get_cache_ids();
mutex_lock(&slab_mutex);
@@ -394,7 +359,6 @@ kmem_cache_create_usercopy(const char *name,
out_unlock:
mutex_unlock(&slab_mutex);
- memcg_put_cache_ids();
put_online_mems();
put_online_cpus();
@@ -507,87 +471,6 @@ static int shutdown_cache(struct kmem_cache *s)
return 0;
}
-#ifdef CONFIG_MEMCG_KMEM
-/*
- * memcg_create_kmem_cache - Create a cache for non-root memory cgroups.
- * @root_cache: The parent of the new cache.
- *
- * This function attempts to create a kmem cache that will serve allocation
- * requests going all non-root memory cgroups to @root_cache. The new cache
- * inherits properties from its parent.
- */
-void memcg_create_kmem_cache(struct kmem_cache *root_cache)
-{
- struct kmem_cache *s = NULL;
- char *cache_name;
-
- get_online_cpus();
- get_online_mems();
-
- mutex_lock(&slab_mutex);
-
- if (root_cache->memcg_params.memcg_cache)
- goto out_unlock;
-
- cache_name = kasprintf(GFP_KERNEL, "%s-memcg", root_cache->name);
- if (!cache_name)
- goto out_unlock;
-
- s = create_cache(cache_name, root_cache->object_size,
- root_cache->align,
- root_cache->flags & CACHE_CREATE_MASK,
- root_cache->useroffset, root_cache->usersize,
- root_cache->ctor, root_cache);
- /*
- * If we could not create a memcg cache, do not complain, because
- * that's not critical at all as we can always proceed with the root
- * cache.
- */
- if (IS_ERR(s)) {
- kfree(cache_name);
- goto out_unlock;
- }
-
- /*
- * Since readers won't lock (see memcg_slab_pre_alloc_hook()), we need a
- * barrier here to ensure nobody will see the kmem_cache partially
- * initialized.
- */
- smp_wmb();
- root_cache->memcg_params.memcg_cache = s;
-
-out_unlock:
- mutex_unlock(&slab_mutex);
-
- put_online_mems();
- put_online_cpus();
-}
-
-static int shutdown_memcg_caches(struct kmem_cache *s)
-{
- BUG_ON(!is_root_cache(s));
-
- if (s->memcg_params.memcg_cache)
- WARN_ON(shutdown_cache(s->memcg_params.memcg_cache));
-
- return 0;
-}
-
-static void cancel_memcg_cache_creation(struct kmem_cache *s)
-{
- cancel_work_sync(&s->memcg_params.work);
-}
-#else
-static inline int shutdown_memcg_caches(struct kmem_cache *s)
-{
- return 0;
-}
-
-static inline void cancel_memcg_cache_creation(struct kmem_cache *s)
-{
-}
-#endif /* CONFIG_MEMCG_KMEM */
-
void slab_kmem_cache_release(struct kmem_cache *s)
{
__kmem_cache_release(s);
@@ -602,8 +485,6 @@ void kmem_cache_destroy(struct kmem_cache *s)
if (unlikely(!s))
return;
- cancel_memcg_cache_creation(s);
-
get_online_cpus();
get_online_mems();
@@ -613,10 +494,7 @@ void kmem_cache_destroy(struct kmem_cache *s)
if (s->refcount)
goto out_unlock;
- err = shutdown_memcg_caches(s);
- if (!err)
- err = shutdown_cache(s);
-
+ err = shutdown_cache(s);
if (err) {
pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
s->name);
@@ -653,33 +531,6 @@ int kmem_cache_shrink(struct kmem_cache *cachep)
}
EXPORT_SYMBOL(kmem_cache_shrink);
-/**
- * kmem_cache_shrink_all - shrink root and memcg caches
- * @s: The cache pointer
- */
-void kmem_cache_shrink_all(struct kmem_cache *s)
-{
- struct kmem_cache *c;
-
- if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || !is_root_cache(s)) {
- kmem_cache_shrink(s);
- return;
- }
-
- get_online_cpus();
- get_online_mems();
- kasan_cache_shrink(s);
- __kmem_cache_shrink(s);
-
- c = memcg_cache(s);
- if (c) {
- kasan_cache_shrink(c);
- __kmem_cache_shrink(c);
- }
- put_online_mems();
- put_online_cpus();
-}
-
bool slab_is_available(void)
{
return slab_state >= UP;
@@ -708,8 +559,6 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
s->useroffset = useroffset;
s->usersize = usersize;
- slab_init_memcg_params(s);
-
err = __kmem_cache_create(s, flags);
if (err)
@@ -1098,25 +947,6 @@ void slab_stop(struct seq_file *m, void *p)
mutex_unlock(&slab_mutex);
}
-static void
-memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
-{
- struct kmem_cache *c;
- struct slabinfo sinfo;
-
- c = memcg_cache(s);
- if (c) {
- memset(&sinfo, 0, sizeof(sinfo));
- get_slabinfo(c, &sinfo);
-
- info->active_slabs += sinfo.active_slabs;
- info->num_slabs += sinfo.num_slabs;
- info->shared_avail += sinfo.shared_avail;
- info->active_objs += sinfo.active_objs;
- info->num_objs += sinfo.num_objs;
- }
-}
-
static void cache_show(struct kmem_cache *s, struct seq_file *m)
{
struct slabinfo sinfo;
@@ -1124,10 +954,8 @@ static void cache_show(struct kmem_cache *s, struct seq_file *m)
memset(&sinfo, 0, sizeof(sinfo));
get_slabinfo(s, &sinfo);
- memcg_accumulate_slabinfo(s, &sinfo);
-
seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
- cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
+ s->name, sinfo.active_objs, sinfo.num_objs, s->size,
sinfo.objects_per_slab, (1 << sinfo.cache_order));
seq_printf(m, " : tunables %4u %4u %4u",
@@ -1144,8 +972,7 @@ static int slab_show(struct seq_file *m, void *p)
if (p == slab_caches.next)
print_slabinfo_header(m);
- if (is_root_cache(s))
- cache_show(s, m);
+ cache_show(s, m);
return 0;
}
@@ -1170,13 +997,13 @@ void dump_unreclaimable_slab(void)
pr_info("Name Used Total\n");
list_for_each_entry_safe(s, s2, &slab_caches, list) {
- if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT))
+ if (s->flags & SLAB_RECLAIM_ACCOUNT)
continue;
get_slabinfo(s, &sinfo);
if (sinfo.num_objs > 0)
- pr_info("%-17s %10luKB %10luKB\n", cache_name(s),
+ pr_info("%-17s %10luKB %10luKB\n", s->name,
(sinfo.active_objs * s->size) / 1024,
(sinfo.num_objs * s->size) / 1024);
}
@@ -1235,53 +1062,6 @@ static int __init slab_proc_init(void)
}
module_init(slab_proc_init);
-#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_MEMCG_KMEM)
-/*
- * Display information about kmem caches that have memcg cache.
- */
-static int memcg_slabinfo_show(struct seq_file *m, void *unused)
-{
- struct kmem_cache *s, *c;
- struct slabinfo sinfo;
-
- mutex_lock(&slab_mutex);
- seq_puts(m, "# <name> <css_id[:dead|deact]> <active_objs> <num_objs>");
- seq_puts(m, " <active_slabs> <num_slabs>\n");
- list_for_each_entry(s, &slab_caches, list) {
- /*
- * Skip kmem caches that don't have the memcg cache.
- */
- if (!s->memcg_params.memcg_cache)
- continue;
-
- memset(&sinfo, 0, sizeof(sinfo));
- get_slabinfo(s, &sinfo);
- seq_printf(m, "%-17s root %6lu %6lu %6lu %6lu\n",
- cache_name(s), sinfo.active_objs, sinfo.num_objs,
- sinfo.active_slabs, sinfo.num_slabs);
-
- c = s->memcg_params.memcg_cache;
- memset(&sinfo, 0, sizeof(sinfo));
- get_slabinfo(c, &sinfo);
- seq_printf(m, "%-17s %4d %6lu %6lu %6lu %6lu\n",
- cache_name(c), root_mem_cgroup->css.id,
- sinfo.active_objs, sinfo.num_objs,
- sinfo.active_slabs, sinfo.num_slabs);
- }
- mutex_unlock(&slab_mutex);
- return 0;
-}
-DEFINE_SHOW_ATTRIBUTE(memcg_slabinfo);
-
-static int __init memcg_slabinfo_init(void)
-{
- debugfs_create_file("memcg_slabinfo", S_IFREG | S_IRUGO,
- NULL, NULL, &memcg_slabinfo_fops);
- return 0;
-}
-
-late_initcall(memcg_slabinfo_init);
-#endif /* CONFIG_DEBUG_FS && CONFIG_MEMCG_KMEM */
#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
static __always_inline void *__do_krealloc(const void *p, size_t new_size,