[kernel] Move mispalced slab_allocated.h

slab_allocated.h had accidentally been placed in src/kernel/objects

src/kernel/slab_allocated.h

@@ -0,0 +1,57 @@
+#pragma once
+/// \file slab_allocated.h
+/// A parent template class for slab-allocated objects
+
+#include <stdlib.h>
+#include <util/pointers.h>
+#include <util/vector.h>
+
+#include "memory.h"
+
+extern uintptr_t g_slabs_bump_pointer;
+
+template <typename T, unsigned N = 1>
+class slab_allocated
+{
+public:
+    constexpr static unsigned slab_pages = N;
+    constexpr static unsigned slab_size = N * mem::frame_size;
+
+    void * operator new(size_t size)
+    {
+        kassert(size == sizeof(T), "Slab allocator got wrong size allocation");
+        if (s_free.count() == 0)
+            allocate_chunk();
+
+        T *item = s_free.pop();
+        memset(item, 0, sizeof(T));
+        return item;
+    }
+
+    void operator delete(void *p) { s_free.append(reinterpret_cast<T*>(p)); }
+
+private:
+    constexpr static size_t per_block = slab_size / sizeof(T);
+
+    static void allocate_chunk()
+    {
+        s_free.ensure_capacity(per_block);
+
+        uintptr_t start = __atomic_fetch_add(
+                &g_slabs_bump_pointer, slab_size,
+                __ATOMIC_SEQ_CST);
+
+        T *current = reinterpret_cast<T*>(start);
+        T *end = util::offset_pointer(current, slab_size);
+        while (current < end)
+            s_free.append(current++);
+    }
+
+    static util::vector<T*> s_free;
+};
+
+template <typename T, unsigned N>
+util::vector<T*> slab_allocated<T,N>::s_free;
+
+#define DEFINE_SLAB_ALLOCATOR(type) \
+    template<> util::vector<typename type*> slab_allocated<typename type, type::slab_pages>::s_free {};