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From: Roman Gushchin <guro@fb.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Shakeel Butt <shakeelb@google.com>, <linux-mm@kvack.org>,
	Vlastimil Babka <vbabka@suse.cz>, <kernel-team@fb.com>,
	<linux-kernel@vger.kernel.org>, Roman Gushchin <guro@fb.com>
Subject: [PATCH v7 15/19] mm: memcg/slab: deprecate slab_root_caches
Date: Mon, 22 Jun 2020 18:58:42 -0700	[thread overview]
Message-ID: <20200623015846.1141975-16-guro@fb.com> (raw)
In-Reply-To: <20200623015846.1141975-1-guro@fb.com>

Currently there are two lists of kmem_caches:
1) slab_caches, which contains all kmem_caches,
2) slab_root_caches, which contains only root kmem_caches.

And there is some preprocessor magic to have a single list if
CONFIG_MEMCG_KMEM isn't enabled.

It was required earlier because the number of non-root kmem_caches was
proportional to the number of memory cgroups and could reach really big
values.  Now, when it cannot exceed the number of root kmem_caches, there
is really no reason to maintain two lists.

We never iterate over the slab_root_caches list on any hot paths, so it's
perfectly fine to iterate over slab_caches and filter out non-root
kmem_caches.

It allows to remove a lot of config-dependent code and two pointers from
the kmem_cache structure.

Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 mm/slab.c        |  1 -
 mm/slab.h        | 17 -----------------
 mm/slab_common.c | 37 ++++++++-----------------------------
 mm/slub.c        |  1 -
 4 files changed, 8 insertions(+), 48 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 84e218fd0bcf..23f0376f66ba 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1239,7 +1239,6 @@ void __init kmem_cache_init(void)
 				  nr_node_ids * sizeof(struct kmem_cache_node *),
 				  SLAB_HWCACHE_ALIGN, 0, 0);
 	list_add(&kmem_cache->list, &slab_caches);
-	memcg_link_cache(kmem_cache);
 	slab_state = PARTIAL;
 
 	/*
diff --git a/mm/slab.h b/mm/slab.h
index d47430e97ff1..46ac1de9a0b7 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -44,14 +44,12 @@ struct kmem_cache {
  *
  * @memcg_cache: pointer to memcg kmem cache, used by all non-root memory
  *		cgroups.
- * @root_caches_node: list node for slab_root_caches list.
  * @work: work struct used to create the non-root cache.
  */
 struct memcg_cache_params {
 	struct kmem_cache *root_cache;
 
 	struct kmem_cache *memcg_cache;
-	struct list_head __root_caches_node;
 	struct work_struct work;
 };
 #endif /* CONFIG_SLOB */
@@ -264,11 +262,6 @@ static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t fla
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-
-/* List of all root caches. */
-extern struct list_head		slab_root_caches;
-#define root_caches_node	memcg_params.__root_caches_node
-
 static inline bool is_root_cache(struct kmem_cache *s)
 {
 	return !s->memcg_params.root_cache;
@@ -446,14 +439,8 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
 }
 
 extern void slab_init_memcg_params(struct kmem_cache *);
-extern void memcg_link_cache(struct kmem_cache *s);
 
 #else /* CONFIG_MEMCG_KMEM */
-
-/* If !memcg, all caches are root. */
-#define slab_root_caches	slab_caches
-#define root_caches_node	list
-
 static inline bool is_root_cache(struct kmem_cache *s)
 {
 	return true;
@@ -522,10 +509,6 @@ static inline void slab_init_memcg_params(struct kmem_cache *s)
 {
 }
 
-static inline void memcg_link_cache(struct kmem_cache *s)
-{
-}
-
 #endif /* CONFIG_MEMCG_KMEM */
 
 static inline struct kmem_cache *virt_to_cache(const void *obj)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index e0a2a904fdd9..0618d3595c08 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -129,9 +129,6 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
 }
 
 #ifdef CONFIG_MEMCG_KMEM
-
-LIST_HEAD(slab_root_caches);
-
 static void memcg_kmem_cache_create_func(struct work_struct *work)
 {
 	struct kmem_cache *cachep = container_of(work, struct kmem_cache,
@@ -154,27 +151,11 @@ static void init_memcg_params(struct kmem_cache *s,
 	else
 		slab_init_memcg_params(s);
 }
-
-void memcg_link_cache(struct kmem_cache *s)
-{
-	if (is_root_cache(s))
-		list_add(&s->root_caches_node, &slab_root_caches);
-}
-
-static void memcg_unlink_cache(struct kmem_cache *s)
-{
-	if (is_root_cache(s))
-		list_del(&s->root_caches_node);
-}
 #else
 static inline void init_memcg_params(struct kmem_cache *s,
 				     struct kmem_cache *root_cache)
 {
 }
-
-static inline void memcg_unlink_cache(struct kmem_cache *s)
-{
-}
 #endif /* CONFIG_MEMCG_KMEM */
 
 /*
@@ -251,7 +232,7 @@ struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
 	if (flags & SLAB_NEVER_MERGE)
 		return NULL;
 
-	list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) {
+	list_for_each_entry_reverse(s, &slab_caches, list) {
 		if (slab_unmergeable(s))
 			continue;
 
@@ -310,7 +291,6 @@ static struct kmem_cache *create_cache(const char *name,
 
 	s->refcount = 1;
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s);
 out:
 	if (err)
 		return ERR_PTR(err);
@@ -505,7 +485,6 @@ static int shutdown_cache(struct kmem_cache *s)
 	if (__kmem_cache_shutdown(s) != 0)
 		return -EBUSY;
 
-	memcg_unlink_cache(s);
 	list_del(&s->list);
 
 	if (s->flags & SLAB_TYPESAFE_BY_RCU) {
@@ -749,7 +728,6 @@ struct kmem_cache *__init create_kmalloc_cache(const char *name,
 
 	create_boot_cache(s, name, size, flags, useroffset, usersize);
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s);
 	s->refcount = 1;
 	return s;
 }
@@ -1090,12 +1068,12 @@ static void print_slabinfo_header(struct seq_file *m)
 void *slab_start(struct seq_file *m, loff_t *pos)
 {
 	mutex_lock(&slab_mutex);
-	return seq_list_start(&slab_root_caches, *pos);
+	return seq_list_start(&slab_caches, *pos);
 }
 
 void *slab_next(struct seq_file *m, void *p, loff_t *pos)
 {
-	return seq_list_next(p, &slab_root_caches, pos);
+	return seq_list_next(p, &slab_caches, pos);
 }
 
 void slab_stop(struct seq_file *m, void *p)
@@ -1148,11 +1126,12 @@ static void cache_show(struct kmem_cache *s, struct seq_file *m)
 
 static int slab_show(struct seq_file *m, void *p)
 {
-	struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node);
+	struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
 
-	if (p == slab_root_caches.next)
+	if (p == slab_caches.next)
 		print_slabinfo_header(m);
-	cache_show(s, m);
+	if (is_root_cache(s))
+		cache_show(s, m);
 	return 0;
 }
 
@@ -1254,7 +1233,7 @@ static int memcg_slabinfo_show(struct seq_file *m, void *unused)
 	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_root_caches, root_caches_node) {
+	list_for_each_entry(s, &slab_caches, list) {
 		/*
 		 * Skip kmem caches that don't have the memcg cache.
 		 */
diff --git a/mm/slub.c b/mm/slub.c
index 91a1dce932e9..7a5d6861b088 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4364,7 +4364,6 @@ static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
 	}
 	slab_init_memcg_params(s);
 	list_add(&s->list, &slab_caches);
-	memcg_link_cache(s);
 	return s;
 }
 
-- 
2.26.2



  parent reply	other threads:[~2020-06-23  1:59 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 02/19] mm: memcg: prepare for byte-sized vmstat items Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 04/19] mm: slub: implement SLUB version of obj_to_index() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 05/19] mm: memcontrol: decouple reference counting from page accounting Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 06/19] mm: memcg/slab: obj_cgroup API Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 07/19] mm: memcg/slab: allocate obj_cgroups for non-root slab pages Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages Roman Gushchin
2020-06-23  5:19   ` Shakeel Butt
2020-06-23  1:58 ` [PATCH v7 10/19] mm: memcg/slab: deprecate memory.kmem.slabinfo Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 11/19] mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 12/19] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 13/19] mm: memcg/slab: simplify memcg cache creation Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 14/19] mm: memcg/slab: remove memcg_kmem_get_cache() Roman Gushchin
2020-06-23  1:58 ` Roman Gushchin [this message]
2020-06-23  1:58 ` [PATCH v7 16/19] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations Roman Gushchin
2020-06-23  5:25   ` Shakeel Butt
2020-06-23  1:58 ` [PATCH v7 18/19] kselftests: cgroup: add kernel memory accounting tests Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 19/19] tools/cgroup: add memcg_slabinfo.py tool Roman Gushchin
2020-06-23 13:53 ` [PATCH v7 00/19] The new cgroup slab memory controller Vlastimil Babka
2020-06-23 15:39   ` Roman Gushchin
2020-06-23 17:40 Roman Gushchin
2020-06-23 17:40 ` [PATCH v7 15/19] mm: memcg/slab: deprecate slab_root_caches Roman Gushchin

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