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>

1 files changed, 29 insertions, 0 deletions

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