mm, sl[aou]b: Common definition for boot state of the slab allocators

All allocators have some sort of support for the bootstrap status.

Setup a common definition for the boot states and make all slab
allocators use that definition.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Reviewed-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

5 files changed, 62 insertions, 56 deletions

diff --git a/mm/slab.c b/mm/slab.c
index 10c821e492bf..59a466b85b0f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -87,6 +87,7 @@
  */
 
 #include        <linux/slab.h>
+#include        "slab.h"
 #include        <linux/mm.h>
 #include        <linux/poison.h>
 #include        <linux/swap.h>
@@ -565,27 +566,6 @@ static struct kmem_cache cache_cache = {
 
 #define BAD_ALIEN_MAGIC 0x01020304ul
 
-/*
- * chicken and egg problem: delay the per-cpu array allocation
- * until the general caches are up.
- */
-static enum {
-        NONE,
-        PARTIAL_AC,
-        PARTIAL_L3,
-        EARLY,
-        LATE,
-        FULL
-} g_cpucache_up;
-
-/*
- * used by boot code to determine if it can use slab based allocator
- */
-int slab_is_available(void)
-{
-        return g_cpucache_up >= EARLY;
-}
-
 #ifdef CONFIG_LOCKDEP
 
 /*
@@ -651,7 +631,7 @@ static void init_node_lock_keys(int q)
 {
         struct cache_sizes *s = malloc_sizes;
 
-        if (g_cpucache_up < LATE)
+        if (slab_state < UP)
                 return;
 
         for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
@@ -1649,14 +1629,14 @@ void __init kmem_cache_init(void)
                 }
         }
 
-        g_cpucache_up = EARLY;
+        slab_state = UP;
 }
 
 void __init kmem_cache_init_late(void)
 {
         struct kmem_cache *cachep;
 
-        g_cpucache_up = LATE;
+        slab_state = UP;
 
         /* Annotate slab for lockdep -- annotate the malloc caches */
         init_lock_keys();
@@ -1668,6 +1648,9 @@ void __init kmem_cache_init_late(void)
                         BUG();
         mutex_unlock(&cache_chain_mutex);
 
+        /* Done! */
+        slab_state = FULL;
+
         /*
          * Register a cpu startup notifier callback that initializes
          * cpu_cache_get for all new cpus
@@ -1699,7 +1682,7 @@ static int __init cpucache_init(void)
                 start_cpu_timer(cpu);
 
         /* Done! */
-        g_cpucache_up = FULL;
+        slab_state = FULL;
         return 0;
 }
 __initcall(cpucache_init);
@@ -2167,10 +2150,10 @@ static size_t calculate_slab_order(struct kmem_cache *cachep,
 
 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
 {
-        if (g_cpucache_up >= LATE)
+        if (slab_state >= FULL)
                 return enable_cpucache(cachep, gfp);
 
-        if (g_cpucache_up == NONE) {
+        if (slab_state == DOWN) {
                 /*
                  * Note: the first kmem_cache_create must create the cache
                  * that's used by kmalloc(24), otherwise the creation of
@@ -2185,16 +2168,16 @@ static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
                  */
                 set_up_list3s(cachep, SIZE_AC);
                 if (INDEX_AC == INDEX_L3)
-                        g_cpucache_up = PARTIAL_L3;
+                        slab_state = PARTIAL_L3;
                 else
-                        g_cpucache_up = PARTIAL_AC;
+                        slab_state = PARTIAL_ARRAYCACHE;
         } else {
                 cachep->array[smp_processor_id()] =
                         kmalloc(sizeof(struct arraycache_init), gfp);
 
-                if (g_cpucache_up == PARTIAL_AC) {
+                if (slab_state == PARTIAL_ARRAYCACHE) {
                         set_up_list3s(cachep, SIZE_L3);
-                        g_cpucache_up = PARTIAL_L3;
+                        slab_state = PARTIAL_L3;
                 } else {
                         int node;
                         for_each_online_node(node) {
diff --git a/mm/slab.h b/mm/slab.h
new file mode 100644
index 000000000000..f9a9815cdc82
--- /dev/null
+++ b/mm/slab.h
@@ -0,0 +1,29 @@
+#ifndef MM_SLAB_H
+#define MM_SLAB_H
+/*
+ * Internal slab definitions
+ */
+
+/*
+ * State of the slab allocator.
+ *
+ * This is used to describe the states of the allocator during bootup.
+ * Allocators use this to gradually bootstrap themselves. Most allocators
+ * have the problem that the structures used for managing slab caches are
+ * allocated from slab caches themselves.
+ */
+enum slab_state {
+        DOWN,                   /* No slab functionality yet */
+        PARTIAL,                /* SLUB: kmem_cache_node available */
+        PARTIAL_ARRAYCACHE,     /* SLAB: kmalloc size for arraycache available */
+        PARTIAL_L3,             /* SLAB: kmalloc size for l3 struct available */
+        UP,                     /* Slab caches usable but not all extras yet */
+        FULL                    /* Everything is working */
+};
+
+extern enum slab_state slab_state;
+
+struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
+        size_t align, unsigned long flags, void (*ctor)(void *));
+
+#endif
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 80412beb67cc..ca1aaf69a1f5 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -16,6 +16,10 @@
 #include <asm/tlbflush.h>
 #include <asm/page.h>
 
+#include "slab.h"
+
+enum slab_state slab_state;
+
 /*
  * kmem_cache_create - Create a cache.
  * @name: A string which is used in /proc/slabinfo to identify this cache.
@@ -66,3 +70,8 @@ out:
         return s;
 }
 EXPORT_SYMBOL(kmem_cache_create);
+
+int slab_is_available(void)
+{
+        return slab_state >= UP;
+}
diff --git a/mm/slob.c b/mm/slob.c
index d63923d549ec..0111e0dece93 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -59,6 +59,8 @@
 
 #include <linux/kernel.h>
 #include <linux/slab.h>
+#include "slab.h"
+
 #include <linux/mm.h>
 #include <linux/swap.h> /* struct reclaim_state */
 #include <linux/cache.h>
@@ -531,6 +533,7 @@ struct kmem_cache *__kmem_cache_create(const char *name, size_t size,
                         c->align = align;
 
                 kmemleak_alloc(c, sizeof(struct kmem_cache), 1, GFP_KERNEL);
+                c->refcount = 1;
         }
         return c;
 }
@@ -616,19 +619,12 @@ int kmem_cache_shrink(struct kmem_cache *d)
 }
 EXPORT_SYMBOL(kmem_cache_shrink);
 
-static unsigned int slob_ready __read_mostly;
-
-int slab_is_available(void)
-{
-        return slob_ready;
-}
-
 void __init kmem_cache_init(void)
 {
-        slob_ready = 1;
+        slab_state = UP;
 }
 
 void __init kmem_cache_init_late(void)
 {
-        /* Nothing to do */
+        slab_state = FULL;
 }
diff --git a/mm/slub.c b/mm/slub.c
index 6551cc9a51f8..4c385164d9f7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -16,6 +16,7 @@
 #include <linux/interrupt.h>
 #include <linux/bitops.h>
 #include <linux/slab.h>
+#include "slab.h"
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 #include <linux/kmemcheck.h>
@@ -182,13 +183,6 @@ static int kmem_size = sizeof(struct kmem_cache);
 static struct notifier_block slab_notifier;
 #endif
 
-static enum {
-        DOWN,           /* No slab functionality available */
-        PARTIAL,        /* Kmem_cache_node works */
-        UP,             /* Everything works but does not show up in sysfs */
-        SYSFS           /* Sysfs up */
-} slab_state = DOWN;
-
 /* A list of all slab caches on the system */
 static DECLARE_RWSEM(slub_lock);
 static LIST_HEAD(slab_caches);
@@ -237,11 +231,6 @@ static inline void stat(const struct kmem_cache *s, enum stat_item si)
  *                      Core slab cache functions
  *******************************************************************/
 
-int slab_is_available(void)
-{
-        return slab_state >= UP;
-}
-
 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 {
         return s->node[node];
@@ -5274,7 +5263,7 @@ static int sysfs_slab_add(struct kmem_cache *s)
         const char *name;
         int unmergeable;
 
-        if (slab_state < SYSFS)
+        if (slab_state < FULL)
                 /* Defer until later */
                 return 0;
 
@@ -5319,7 +5308,7 @@ static int sysfs_slab_add(struct kmem_cache *s)
 
 static void sysfs_slab_remove(struct kmem_cache *s)
 {
-        if (slab_state < SYSFS)
+        if (slab_state < FULL)
                 /*
                  * Sysfs has not been setup yet so no need to remove the
                  * cache from sysfs.
@@ -5347,7 +5336,7 @@ static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
 {
         struct saved_alias *al;
 
-        if (slab_state == SYSFS) {
+        if (slab_state == FULL) {
                 /*
                  * If we have a leftover link then remove it.
                  */
@@ -5380,7 +5369,7 @@ static int __init slab_sysfs_init(void)
                 return -ENOSYS;
         }
 
-        slab_state = SYSFS;
+        slab_state = FULL;
 
         list_for_each_entry(s, &slab_caches, list) {
                 err = sysfs_slab_add(s);