Initial commit - slab allocator, kmalloc, other re

factors

src/mm/slab.h

@@ -0,0 +1,57 @@
+#include <stdatomic.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <error.h>
+#include <stdbool.h>
+
+#pragma once
+#define KCACHE_NAME_LEN 16
+
+
+struct ma_bufctl {
+    struct ma_bufctl *next;
+    size_t *startaddr;
+};
+
+struct ma_slab {
+    struct ma_kcache *cache;
+
+    struct ma_slab *next;
+    struct ma_slab *prev;
+
+    uint32_t refcount; // The amount of active (not free) objects in the slabs
+
+    struct ma_bufctl *free; // Linked list of free buffers in the slab. Is equal to NULL once there are no more free objects 
+};
+
+/* objrefs are used to be able to quickly find out which slab and cache a object belongs to. objrefs belonging to the same slab are kept in one page, there is no mixing. */
+struct ma_objref { 
+    struct ma_objref *next;
+    struct ma_objref *prev;
+    void *addr; // Addr of the object
+    struct ma_slab *slab; // The slab which the obj belongs to
+    struct ma_kcache *kcache; // The cache which the obj belongs to
+};
+
+struct ma_kcache {
+    struct ma_kcache *next;    
+    struct ma_kcache *prev;
+
+    uint32_t objsize; // Size of the object which the cache stores
+    uint16_t flags; // Not useful yet
+    uint32_t num; // Number of objects per slab
+    uint32_t slabsize; // How many pages does a single slab take up. Useful for objects > PAGE_SIZE
+    
+    struct ma_slab *slabs_free;
+    struct ma_slab *slabs_partial;
+    struct ma_slab *slabs_used;
+
+    atomic_flag lock;
+
+    char name[KCACHE_NAME_LEN];
+};
+
+void *ma_cache_alloc(struct ma_kcache *kcache, uint32_t flags);
+kstatus ma_cache_dealloc(void *object);
+struct ma_kcache *ma_cache_create(char *name, size_t size, uint32_t flags, void (*constructor)(void *, size_t), void (*destructor)(void *, size_t));
+void cache_info(struct ma_kcache *cache);