From c6c3a556b332b7d5a1e539f920345e79edb16a31 Mon Sep 17 00:00:00 2001
From: "Justin C. Miller" <justin@devjustinian.com>
Date: Sun, 31 May 2020 18:22:23 -0700
Subject: [PATCH] [kernel] Remove explicit allocator passing

Many kernel objects had to keep a hold of refrences to allocators in
order to pass them on down the call chain. Remove those explicit
refrences and use `operator new`, `operator delete`, and define new
`kalloc` and `kfree`.

Also remove `slab_allocator` and replace it with a new mixin for slab
allocation, `slab_allocated`, that overrides `operator new` and
`operator free` for its subclass.

Remove some no longer used related headers, `buddy_allocator.h` and
`address_manager.h`

Tags: memory
---
 src/kernel/device_manager.cpp                 |   7 +-
 src/kernel/main.cpp                           |   6 +-
 src/kernel/memory_bootstrap.cpp               |   8 +-
 src/kernel/objects/kobject.cpp                |   1 -
 src/kernel/process.cpp                        |   5 +-
 src/kernel/scheduler.cpp                      |  13 +-
 src/kernel/scheduler.h                        |   7 +-
 src/libraries/initrd/include/initrd/initrd.h  |   2 +-
 src/libraries/initrd/initrd.cpp               |   3 +-
 .../kutil/include/kutil/address_manager.h     |  15 -
 src/libraries/kutil/include/kutil/avl_tree.h  |  18 +-
 .../kutil/include/kutil/buddy_allocator.h     | 302 ------------------
 src/libraries/kutil/include/kutil/memory.h    |  13 +-
 .../kutil/include/kutil/slab_allocated.h      |  52 +++
 .../kutil/include/kutil/slab_allocator.h      |  72 -----
 src/libraries/kutil/include/kutil/vector.h    |  31 +-
 src/libraries/kutil/include/kutil/vm_space.h  |   6 +-
 src/libraries/kutil/vm_space.cpp              |  23 +-
 src/tests/address_manager.cpp                 |  78 -----
 19 files changed, 125 insertions(+), 537 deletions(-)
 delete mode 100644 src/libraries/kutil/include/kutil/address_manager.h
 delete mode 100644 src/libraries/kutil/include/kutil/buddy_allocator.h
 create mode 100644 src/libraries/kutil/include/kutil/slab_allocated.h
 delete mode 100644 src/libraries/kutil/include/kutil/slab_allocator.h
 delete mode 100644 src/tests/address_manager.cpp

diff --git a/src/kernel/device_manager.cpp b/src/kernel/device_manager.cpp
index 2ae96dd..92e3ea2 100644
--- a/src/kernel/device_manager.cpp
+++ b/src/kernel/device_manager.cpp
@@ -60,12 +60,7 @@ void irq4_callback(void *)
 
 
 device_manager::device_manager(const void *root_table, kutil::allocator &alloc) :
-	m_lapic(nullptr),
-	m_ioapics(alloc),
-	m_pci(alloc),
-	m_devices(alloc),
-	m_irqs(alloc),
-	m_blockdevs(alloc)
+	m_lapic(nullptr)
 {
 	kassert(root_table != 0, "ACPI root table pointer is null.");
 
diff --git a/src/kernel/main.cpp b/src/kernel/main.cpp
index aca26fc..645d162 100644
--- a/src/kernel/main.cpp
+++ b/src/kernel/main.cpp
@@ -99,13 +99,13 @@ kernel_main(args::header *header)
 	log::debug(logs::boot, "Runtime service is at: %016lx", header->runtime_services);
 
 	// Load the module tagged as initrd
-	kutil::vector<initrd::disk> initrds(heap);
+	kutil::vector<initrd::disk> initrds;
 	for (unsigned i = 0; i < header->num_modules; ++i) {
 		args::module &mod = header->modules[i];
 		if (mod.type != args::mod_type::initrd)
 			continue;
 
-		initrd::disk &ird = initrds.emplace(mod.location, heap);
+		initrd::disk &ird = initrds.emplace(mod.location);
 		log::info(logs::boot, "initrd loaded with %d files.", ird.files().count());
 		for (auto &f : ird.files())
 			log::info(logs::boot, "  %s%s (%d bytes).", f.executable() ? "*" : "", f.name(), f.size());
@@ -159,7 +159,7 @@ kernel_main(args::header *header)
 	devices->get_lapic()->calibrate_timer();
 
 	syscall_enable();
-	scheduler *sched = new (&scheduler::get()) scheduler(devices->get_lapic(), heap);
+	scheduler *sched = new (&scheduler::get()) scheduler(devices->get_lapic());
 
 	sched->create_kernel_task(-1, logger_task);
 
diff --git a/src/kernel/memory_bootstrap.cpp b/src/kernel/memory_bootstrap.cpp
index 4e413f9..150596e 100644
--- a/src/kernel/memory_bootstrap.cpp
+++ b/src/kernel/memory_bootstrap.cpp
@@ -31,6 +31,11 @@ void * operator new [] (size_t size)       { return g_kernel_heap.allocate(size)
 void operator delete (void *p) noexcept    { return g_kernel_heap.free(p); }
 void operator delete [] (void *p) noexcept { return g_kernel_heap.free(p); }
 
+namespace kutil {
+void * kalloc(size_t size) { return g_kernel_heap.allocate(size); }
+void kfree(void *p) { return g_kernel_heap.free(p); }
+}
+
 void walk_page_table(
 	page_table *table,
 	page_table::level level,
@@ -90,8 +95,7 @@ memory_initialize(args::header *kargs)
 
 	new (&g_kernel_space) kutil::vm_space {
 		kernel_offset,
-		(page_offset-kernel_offset),
-		g_kernel_heap};
+		(page_offset-kernel_offset)};
 
 
 	uintptr_t current_start = 0;
diff --git a/src/kernel/objects/kobject.cpp b/src/kernel/objects/kobject.cpp
index 64bc8af..a8662a1 100644
--- a/src/kernel/objects/kobject.cpp
+++ b/src/kernel/objects/kobject.cpp
@@ -12,7 +12,6 @@ static j6_koid_t next_koid;
 kobject::kobject(type t, j6_signal_t signals) :
 	m_koid(koid_generate(t)),
 	m_signals(signals),
-	m_observers(g_kernel_heap),
 	m_handle_count(0)
 {}
 
diff --git a/src/kernel/process.cpp b/src/kernel/process.cpp
index 79dcbe3..de3995d 100644
--- a/src/kernel/process.cpp
+++ b/src/kernel/process.cpp
@@ -1,4 +1,4 @@
-#include "kutil/heap_allocator.h"
+#include "kutil/assert.h"
 #include "cpu.h"
 #include "debug.h"
 #include "log.h"
@@ -6,7 +6,6 @@
 #include "scheduler.h"
 
 extern "C" void task_fork_return_thunk();
-extern kutil::heap_allocator g_kernel_heap; // TODO: this is a bad hack to get access to the heap
 
 void
 process::exit(uint32_t code)
@@ -68,7 +67,7 @@ process::setup_kernel_stack()
 	constexpr unsigned null_frame_entries = 2;
 	constexpr size_t null_frame_size = null_frame_entries * sizeof(uint64_t);
 
-	void *stack_bottom = g_kernel_heap.allocate(initial_stack_size);
+	void *stack_bottom = kutil::kalloc(initial_stack_size);
 	kutil::memset(stack_bottom, 0, initial_stack_size);
 
 	log::debug(logs::memory, "Created kernel stack at %016lx size 0x%lx",
diff --git a/src/kernel/scheduler.cpp b/src/kernel/scheduler.cpp
index 802a8fc..3a33ea6 100644
--- a/src/kernel/scheduler.cpp
+++ b/src/kernel/scheduler.cpp
@@ -16,7 +16,7 @@
 
 using memory::initial_stack;
 
-scheduler scheduler::s_instance(nullptr, kutil::allocator::invalid);
+scheduler scheduler::s_instance(nullptr);
 
 const uint64_t rflags_noint = 0x002;
 const uint64_t rflags_int = 0x202;
@@ -28,12 +28,11 @@ extern "C" {
 
 extern uint64_t idle_stack_end;
 
-scheduler::scheduler(lapic *apic, kutil::allocator &alloc) :
+scheduler::scheduler(lapic *apic) :
 	m_apic(apic),
-	m_next_pid(1),
-	m_process_allocator(alloc)
+	m_next_pid(1)
 {
-	auto *idle = m_process_allocator.pop();
+	auto *idle = new process_node;
 	uint8_t last_pri = num_priorities - 1;
 
 	// The kernel idle task, also the thread we're in now
@@ -121,7 +120,7 @@ scheduler::create_process(pid_t pid)
 {
 	kassert(pid <= 0, "Cannot specify a positive pid in create_process");
 
-	auto *proc = m_process_allocator.pop();
+	auto *proc = new process_node;
 	proc->pid = pid ? pid : m_next_pid++;
 	proc->priority = default_priority;
 	return proc;
@@ -233,7 +232,7 @@ void scheduler::prune(uint64_t now)
 				if (parent && parent->wake_on_child(remove)) {
 					m_blocked.remove(parent);
 					m_runlists[parent->priority].push_front(parent);
-					m_process_allocator.push(remove);
+					delete remove;
 				} else {
 					m_exited.push_back(remove);
 				}
diff --git a/src/kernel/scheduler.h b/src/kernel/scheduler.h
index c88faf9..245673f 100644
--- a/src/kernel/scheduler.h
+++ b/src/kernel/scheduler.h
@@ -4,7 +4,6 @@
 
 #include <stdint.h>
 #include "kutil/allocator.h"
-#include "kutil/slab_allocator.h"
 #include "process.h"
 
 class lapic;
@@ -31,8 +30,7 @@ public:
 
 	/// Constructor.
 	/// \arg apic  Pointer to the local APIC object
-	/// \arg alloc Allocator to use for TCBs
-	scheduler(lapic *apic, kutil::allocator &alloc);
+	scheduler(lapic *apic);
 
 	/// Create a new process from a program image in memory.
 	/// \arg name  Name of the program image
@@ -86,9 +84,6 @@ private:
 	uint32_t m_next_pid;
 	uint32_t m_tick_count;
 
-	using process_slab = kutil::slab_allocator<process>;
-	process_slab m_process_allocator;
-
 	process_node *m_current;
 	process_list m_runlists[num_priorities];
 	process_list m_blocked;
diff --git a/src/libraries/initrd/include/initrd/initrd.h b/src/libraries/initrd/include/initrd/initrd.h
index 5a48844..ed8a676 100644
--- a/src/libraries/initrd/include/initrd/initrd.h
+++ b/src/libraries/initrd/include/initrd/initrd.h
@@ -49,7 +49,7 @@ class disk
 public:
 	/// Constructor.
 	/// \arg start  The start of the initrd in memory
-	disk(const void *start, kutil::allocator &alloc);
+	disk(const void *start);
 
 	/// Get the vector of files on the disk
 	const kutil::vector<file> & files() const { return m_files; }
diff --git a/src/libraries/initrd/initrd.cpp b/src/libraries/initrd/initrd.cpp
index dad412d..bfd2fd7 100644
--- a/src/libraries/initrd/initrd.cpp
+++ b/src/libraries/initrd/initrd.cpp
@@ -23,8 +23,7 @@ file::executable() const {
 }
 
 
-disk::disk(const void *start, kutil::allocator &alloc) :
-	m_files(alloc)
+disk::disk(const void *start)
 {
 	auto *header = reinterpret_cast<const disk_header *>(start);
 	size_t length = header->length;
diff --git a/src/libraries/kutil/include/kutil/address_manager.h b/src/libraries/kutil/include/kutil/address_manager.h
deleted file mode 100644
index b2c21c1..0000000
--- a/src/libraries/kutil/include/kutil/address_manager.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#pragma once
-/// \file address_manager.h
-/// The virtual memory address space manager
-
-#include "kutil/buddy_allocator.h"
-
-namespace kutil {
-
-using address_manager =
-	buddy_allocator<
-		12,  // Min allocation:  4KiB
-		36   // Max allocation: 64GiB
-	>;
-
-} //namespace kutil
diff --git a/src/libraries/kutil/include/kutil/avl_tree.h b/src/libraries/kutil/include/kutil/avl_tree.h
index 80ac5a6..39d95d0 100644
--- a/src/libraries/kutil/include/kutil/avl_tree.h
+++ b/src/libraries/kutil/include/kutil/avl_tree.h
@@ -5,6 +5,7 @@
 #include <algorithm>
 #include <stdint.h>
 #include "kutil/assert.h"
+#include "kutil/slab_allocated.h"
 
 namespace kutil {
 
@@ -14,7 +15,8 @@ template <typename T> class avl_tree;
 /// A node in a `avl_tree<T>`
 template <typename T>
 class avl_node :
-	public T
+	public T,
+	public slab_allocated<avl_node<T>>
 {
 public:
 	using item_type = T;
@@ -151,7 +153,7 @@ private:
 		return existing;
 	}
 
-	static node_type * remove(node_type *existing, node_type *subtrahend, allocator &alloc)
+	static node_type * remove(node_type *existing, node_type *subtrahend)
 	{
 		if (existing == nullptr)
 			return existing;
@@ -170,7 +172,7 @@ private:
 					*existing = *temp;
 				}
 
-				alloc.free(temp);
+				delete temp;
 			} else {
 				// Both children exist, find next node
 				node_type *temp = existing->m_right;
@@ -178,12 +180,12 @@ private:
 					temp = temp->m_left;
 
 				*existing = *temp;
-				existing->m_right = remove(existing->m_right, temp, alloc);
+				existing->m_right = remove(existing->m_right, temp);
 			}
 		} else if (existing->compare(subtrahend) < 0) {
-			existing->m_left = remove(existing->m_left, subtrahend, alloc);
+			existing->m_left = remove(existing->m_left, subtrahend);
 		} else {
-			existing->m_right = remove(existing->m_right, subtrahend, alloc);
+			existing->m_right = remove(existing->m_right, subtrahend);
 		}
 
 		if (!existing)
@@ -232,8 +234,8 @@ public:
 	inline node_type * root() { return m_root; }
 	inline unsigned count() const { return m_count; }
 
-	inline void remove(node_type *subtrahend, allocator &alloc) {
-		m_root = node_type::remove(m_root, subtrahend, alloc);
+	inline void remove(node_type *subtrahend) {
+		m_root = node_type::remove(m_root, subtrahend);
 		m_count--;
 	}
 
diff --git a/src/libraries/kutil/include/kutil/buddy_allocator.h b/src/libraries/kutil/include/kutil/buddy_allocator.h
deleted file mode 100644
index 1ff09e6..0000000
--- a/src/libraries/kutil/include/kutil/buddy_allocator.h
+++ /dev/null
@@ -1,302 +0,0 @@
-#pragma once
-/// \file buddy_allocator.h
-/// Helper base class for buddy allocators with external node storage.
-
-#include <stdint.h>
-#include <utility>
-#include "kutil/assert.h"
-#include "kutil/linked_list.h"
-#include "kutil/slab_allocator.h"
-
-namespace kutil {
-
-struct buddy_region;
-
-
-template<
-	unsigned size_min,
-	unsigned size_max,
-	typename region_type = buddy_region>
-class buddy_allocator
-{
-public:
-	using region_node = list_node<region_type>;
-	using region_list = linked_list<region_type>;
-
-	static const size_t min_alloc = (1 << size_min);
-	static const size_t max_alloc = (1 << size_max);
-
-	/// Default constructor creates an invalid object.
-	buddy_allocator() : m_alloc(allocator::invalid) {}
-
-	/// Constructor.
-	/// \arg alloc  Allocator to use for region nodes
-	buddy_allocator(allocator &alloc) : m_alloc(alloc) {}
-
-	/// Move-like constructor. Takes ownership of existing regions.
-	buddy_allocator(buddy_allocator &&other, allocator &alloc) :
-		m_alloc(alloc)
-	{
-		for (unsigned i = 0; i < buckets; ++i) {
-			m_free[i] = std::move(other.m_free[i]);
-			m_used[i] = std::move(other.m_used[i]);
-		}
-	}
-
-	/// Add address space to be managed.
-	/// \arg start   Initial address in the managed range
-	/// \arg length  Size of the managed range, in bytes
-	void add_regions(uintptr_t start, size_t length)
-	{
-		uintptr_t p = start;
-		unsigned size = size_max;
-
-		while (size >= size_min) {
-			size_t chunk_size = 1ull << size;
-
-			while (p + chunk_size <= start + length) {
-				region_node *r = m_alloc.pop();
-				r->size = size_max;
-				r->address = p;
-
-				free_bucket(size).sorted_insert(r);
-				p += chunk_size;
-			}
-
-			size--;
-		}
-	}
-
-	/// Allocate address space from the managed area.
-	/// \arg length  The amount of memory to allocate, in bytes
-	/// \returns     The address of the start of the allocated area, or 0 on
-	///              failure
-	uintptr_t allocate(size_t length)
-	{
-		unsigned size = size_min;
-		while ((1ull << size) < length)
-			if (size++ == size_max)
-				return 0;
-
-		unsigned request = size;
-		while (free_bucket(request).empty())
-			if (request++ == size_max)
-				return 0;
-
-		region_node *r = nullptr;
-		while (request > size) {
-			r = free_bucket(request).pop_front();
-			region_node *n = split(r);
-			request--;
-
-			free_bucket(request).sorted_insert(n);
-			if (request != size)
-				free_bucket(request).sorted_insert(r);
-		}
-
-		if (r == nullptr) r = free_bucket(size).pop_front();
-		used_bucket(size).sorted_insert(r);
-
-		return r->address;
-	}
-
-	/// Mark a region as allocated.
-	/// \arg start   The start of the region
-	/// \arg length  The size of the region, in bytes
-	/// \returns     The address of the start of the allocated area, or 0 on
-	///              failure. This may be less than `start`.
-	uintptr_t mark(uintptr_t start, size_t length)
-	{
-		uintptr_t end = start + length;
-		region_node *found = nullptr;
-
-		for (unsigned i = size_max; i >= size_min && !found; --i) {
-			for (auto *r : free_bucket(i)) {
-				if (start >= r->address && end <= r->end()) {
-					free_bucket(i).remove(r);
-					found = r;
-					break;
-				}
-			}
-		}
-
-		kassert(found, "buddy_allocator::mark called for unknown region");
-		if (!found)
-			return 0;
-
-		found = maybe_split(found, start, end);
-		used_bucket(found->size).sorted_insert(found);
-		return found->address;
-	}
-
-	/// Mark a region as permanently allocated. The region is not returned,
-	/// as the block can never be freed. This may remove several smaller
-	/// regions in order to more closely fit the region described.
-	/// \arg start   The start of the region
-	/// \arg length  The size of the region, in bytes
-	/// \returns     The address of the start of the allocated area, or 0 on
-	///              failure. This may be less than `start`.
-	void mark_permanent(uintptr_t start, size_t length)
-	{
-		uintptr_t end = start + length;
-		for (unsigned i = size_max; i >= size_min; --i) {
-			for (auto *r : free_bucket(i)) {
-				if (start >= r->address && end <= r->end()) {
-					free_bucket(i).remove(r);
-					delete_region(r, start, end);
-					return;
-				}
-			}
-		}
-
-		kassert(false, "buddy_allocator::mark_permanent called for unknown region");
-	}
-
-	/// Free a previous allocation.
-	/// \arg p  An address previously retuned by allocate()
-	void free(uintptr_t p)
-	{
-		region_node *found = find(p, true);
-
-		kassert(found, "buddy_allocator::free called for unknown region");
-		if (!found)
-			return;
-
-		used_bucket(found->size).remove(found);
-		free_bucket(found->size).sorted_insert(found);
-
-		while (auto *bud = get_buddy(found)) {
-			region_node *eld = found->elder() ? found : bud;
-			region_node *other = found->elder() ? bud : found;
-
-			free_bucket(other->size).remove(other);
-			m_alloc.push(other);
-
-			free_bucket(eld->size).remove(eld);
-			eld->size++;
-			free_bucket(eld->size).sorted_insert(eld);
-
-			found = eld;
-		}
-	}
-
-	/// Check if an allocation exists
-	/// \arg addr  Address within the managed space
-	/// \returns   True if the address is in a region currently allocated
-	bool contains(uintptr_t addr)
-	{
-		for (unsigned i = size_max; i >= size_min; --i) {
-			for (auto *r : used_bucket(i)) {
-				if (r->contains(addr))
-					return true;
-				else if (r->address < addr)
-					break;
-			}
-		}
-
-		return false;
-	}
-
-protected:
-	/// Split a region of the given size into two smaller regions, returning
-	/// the new latter half
-	region_node * split(region_node *reg)
-	{
-		region_node *other = m_alloc.pop();
-
-		other->size = --reg->size;
-		other->address = reg->address + (1ull << reg->size);
-		return other;
-	}
-
-	/// Find a node with the given address
-	region_node * find(uintptr_t p, bool used = true)
-	{
-		for (unsigned size = size_max; size >= size_min; --size) {
-			auto &list = used ? used_bucket(size) : free_bucket(size);
-			for (auto *f : list) {
-				if (f->address < p) continue;
-				if (f->address == p) return f;
-				break;
-			}
-		}
-		return nullptr;
-	}
-
-	/// Helper to get the buddy for a node, if it's adjacent
-	region_node * get_buddy(region_node *r)
-	{
-		region_node *b = r->elder() ? r->next() : r->prev();
-		if (b && b->address == r->buddy())
-			return b;
-		return nullptr;
-	}
-
-	region_node * maybe_split(region_node *reg, uintptr_t start, uintptr_t end)
-	{
-		while (reg->size > size_min) {
-			// Split if the request fits in the second half
-			if (start >= reg->half()) {
-				region_node *other = split(reg);
-				free_bucket(reg->size).sorted_insert(reg);
-				reg = other;
-			}
-
-			// Split if the request fits in the first half
-			else if (end <= reg->half()) {
-				region_node *other = split(reg);
-				free_bucket(other->size).sorted_insert(other);
-			}
-
-			// If neither, we've split as much as possible
-			else break;
-		}
-
-		return reg;
-	}
-
-	void delete_region(region_node *reg, uintptr_t start, uintptr_t end)
-	{
-		reg = maybe_split(reg, start, end);
-
-		size_t leading = start - reg->address;
-		size_t trailing = reg->end() - end;
-		if (leading > (1<<size_min) || trailing > (1<<size_min)) {
-			region_node *tail = split(reg);
-			delete_region(reg, start, reg->end());
-			delete_region(tail, tail->address, end);
-		} else {
-			m_alloc.push(reg);
-		}
-	}
-
-	region_list & used_bucket(unsigned size) { return m_used[size - size_min]; }
-	region_list & free_bucket(unsigned size) { return m_free[size - size_min]; }
-
-	static const unsigned buckets = (size_max - size_min + 1);
-
-	region_list m_free[buckets];
-	region_list m_used[buckets];
-	slab_allocator<region_type> m_alloc;
-};
-
-
-struct buddy_region
-{
-	inline int compare(const buddy_region *o) const {
-		return address > o->address ? 1 : \
-			address < o->address ? -1 : 0;
-	}
-
-	inline uintptr_t end() const { return address + (1ull << size); }
-	inline uintptr_t half() const { return address + (1ull << (size - 1)); }
-	inline bool contains(uintptr_t p) const { return p >= address && p < end(); }
-
-	inline uintptr_t buddy() const { return address ^ (1ull << size); }
-	inline bool elder() const { return address < buddy(); }
-
-	uint16_t size;
-	uintptr_t address;
-};
-
-} // namespace kutil
diff --git a/src/libraries/kutil/include/kutil/memory.h b/src/libraries/kutil/include/kutil/memory.h
index f5bbca2..cf767a5 100644
--- a/src/libraries/kutil/include/kutil/memory.h
+++ b/src/libraries/kutil/include/kutil/memory.h
@@ -6,9 +6,20 @@
 
 void * operator new (size_t, void *p) noexcept;
 
-
 namespace kutil {
 
+/// Allocate from the default allocator. Note this needs to be
+/// implemented by users of the kutil library.
+/// \arg size  The size in bytes requested
+/// \returns   A pointer to the newly allocated memory,
+///            or nullptr on error
+void * kalloc(size_t size);
+
+/// Free memory allocated by `kalloc`. Note this needs to be
+/// implemented by users of the kutil library.
+/// \arg p  Pointer that was returned from a `kalloc` call
+void kfree(void *p);
+
 /// Fill memory with the given value.
 /// \arg p   The beginning of the memory area to fill
 /// \arg v   The byte value to fill memory with
diff --git a/src/libraries/kutil/include/kutil/slab_allocated.h b/src/libraries/kutil/include/kutil/slab_allocated.h
new file mode 100644
index 0000000..d0be1d6
--- /dev/null
+++ b/src/libraries/kutil/include/kutil/slab_allocated.h
@@ -0,0 +1,52 @@
+#pragma once
+/// \file slab_allocated.h
+/// A parent template class for slab-allocated objects
+
+#include "kernel_memory.h"
+#include "kutil/memory.h"
+#include "kutil/vector.h"
+
+namespace kutil {
+
+template <typename T, unsigned N = 1>
+class slab_allocated
+{
+public:
+	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();
+		kutil::memset(item, 0, sizeof(T));
+		return item;
+	}
+
+	void operator delete(void *p) { s_free.append(reinterpret_cast<T*>(p)); }
+
+	// TODO: get rid of this terribleness
+	static void hacky_init_remove_me() {
+		memset(&s_free, 0, sizeof(s_free));
+	}
+
+private:
+	static void allocate_chunk()
+	{
+		size_t size = N * ::memory::frame_size;
+		s_free.ensure_capacity(size / sizeof(T));
+
+		void *memory = kalloc(size);
+		T *current = reinterpret_cast<T *>(memory); 
+		T *end = offset_pointer(current, size);
+		while (current < end)
+			s_free.append(current++);
+	}
+
+	static vector<T*> s_free;
+};
+
+#define DEFINE_SLAB_ALLOCATOR(type, N) \
+	template<> ::kutil::vector<type*> kutil::slab_allocated<type, N>::s_free {};
+
+} // namespace kutil
diff --git a/src/libraries/kutil/include/kutil/slab_allocator.h b/src/libraries/kutil/include/kutil/slab_allocator.h
deleted file mode 100644
index 80e1aa6..0000000
--- a/src/libraries/kutil/include/kutil/slab_allocator.h
+++ /dev/null
@@ -1,72 +0,0 @@
-#pragma once
-/// \file slab_allocator.h
-/// A slab allocator and related definitions
-#include "kutil/allocator.h"
-#include "kutil/assert.h"
-#include "kutil/linked_list.h"
-#include "kutil/memory.h"
-
-namespace kutil {
-
-
-/// A slab allocator for small structures kept in a linked list
-template <typename T, size_t N = memory::frame_size>
-class slab_allocator :
-	public linked_list<T>,
-	public allocator
-{
-public:
-	using item_type = list_node<T>;
-
-	/// Default constructor.
-	/// \arg alloc      The allocator to use to allocate chunks. Defaults to malloc().
-	slab_allocator(allocator &alloc) :
-		m_alloc(alloc) {}
-
-	/// Allocator interface implementation
-	virtual void * allocate(size_t size) override
-	{
-		kassert(size == sizeof(T), "Asked slab allocator for wrong size");
-		if (size != sizeof(T)) return 0;
-		return pop();
-	}
-
-	/// Allocator interface implementation
-	virtual void free(void *p) override
-	{
-		push(static_cast<item_type*>(p));
-	}
-
-	/// Get an item from the cache. May allocate a new chunk if the cache is empty.
-	/// \returns  An allocated element
-	inline item_type * pop()
-	{
-		if (this->empty()) this->allocate_chunk();
-		kassert(!this->empty(), "Slab allocator is empty after allocate()");
-		item_type *item = this->pop_front();
-		kutil::memset(item, 0, sizeof(item_type));
-		return item;
-	}
-
-	/// Return an item to the cache.
-	/// \arg item  A previously allocated element
-	inline void push(item_type *item)
-	{
-		this->push_front(item);
-	}
-
-private:
-	void allocate_chunk()
-	{
-		constexpr unsigned count = N / sizeof(item_type);
-
-		void *memory = m_alloc.allocate(N);
-		item_type *items = reinterpret_cast<item_type *>(memory); 
-		for (size_t i = 0; i < count; ++i)
-			this->push_back(&items[i]);
-	}
-
-	allocator& m_alloc;
-};
-
-} // namespace kutil
diff --git a/src/libraries/kutil/include/kutil/vector.h b/src/libraries/kutil/include/kutil/vector.h
index 441dbc5..c9152e4 100644
--- a/src/libraries/kutil/include/kutil/vector.h
+++ b/src/libraries/kutil/include/kutil/vector.h
@@ -15,20 +15,18 @@ class vector
 {
 public:
 	/// Default constructor. Creates an empty vector with no capacity.
-	vector(kutil::allocator &alloc = allocator::invalid) :
+	vector() :
 		m_size(0),
 		m_capacity(0),
-		m_elements(nullptr),
-		m_alloc(alloc)
+		m_elements(nullptr)
 	{}
 
 	/// Constructor. Creates an empty array with capacity.
 	/// \arg capacity  Initial capacity to allocate
-	vector(size_t capacity, allocator &alloc) :
+	vector(size_t capacity) :
 		m_size(0),
 		m_capacity(0),
-		m_elements(nullptr),
-		m_alloc(alloc)
+		m_elements(nullptr)
 	{
 		set_capacity(capacity);
 	}
@@ -37,8 +35,7 @@ public:
 	vector(const vector& other) :
 		m_size(0),
 		m_capacity(0),
-		m_elements(nullptr),
-		m_alloc(other.m_alloc)
+		m_elements(nullptr)
 	{
 		set_capacity(other.m_capacity);
 		kutil::memcpy(m_elements, other.m_elements, other.m_size * sizeof(T));
@@ -49,8 +46,7 @@ public:
 	vector(vector&& other) :
 		m_size(other.m_size),
 		m_capacity(other.m_capacity),
-		m_elements(other.m_elements),
-		m_alloc(other.m_alloc)
+		m_elements(other.m_elements)
 	{
 		other.m_size = 0;
 		other.m_capacity = 0;
@@ -61,7 +57,7 @@ public:
 	~vector()
 	{
 		while (m_size) remove();
-		m_alloc.free(m_elements);
+		kfree(m_elements);
 	}
 
 	/// Get the size of the array.
@@ -117,6 +113,14 @@ public:
 		m_elements[m_size].~T();
 	}
 
+	/// Remove an item from the end of the array and return it.
+	T pop()
+	{
+		T temp = m_elements[m_size - 1];
+		remove();
+		return temp;
+	}
+
 	/// Set the size of the array. Any new items are default constructed.
 	/// Any items past the end are deleted. The array is realloced if needed.
 	/// \arg size  The new size
@@ -149,7 +153,7 @@ public:
 	/// \arg capacity  Number of elements to allocate
 	void set_capacity(size_t capacity)
 	{
-		T *new_array = m_alloc.allocate<T>(capacity);
+		T *new_array = reinterpret_cast<T*>(kalloc(capacity * sizeof(T)));
 		size_t size = std::min(capacity, m_size);
 
 		kutil::memcpy(new_array, m_elements, size * sizeof(T));
@@ -158,7 +162,7 @@ public:
 		m_size = size;
 		m_capacity = capacity;
 
-		m_alloc.free(m_elements);
+		kfree(m_elements);
 		m_elements = new_array;
 	}
 
@@ -166,7 +170,6 @@ private:
 	size_t m_size;
 	size_t m_capacity;
 	T *m_elements;
-	allocator &m_alloc;
 };
 
 } // namespace kutil
diff --git a/src/libraries/kutil/include/kutil/vm_space.h b/src/libraries/kutil/include/kutil/vm_space.h
index 601fab8..cf135ae 100644
--- a/src/libraries/kutil/include/kutil/vm_space.h
+++ b/src/libraries/kutil/include/kutil/vm_space.h
@@ -5,7 +5,6 @@
 #include <stdint.h>
 #include "kutil/allocator.h"
 #include "kutil/avl_tree.h"
-#include "kutil/slab_allocator.h"
 
 namespace kutil {
 
@@ -39,8 +38,7 @@ public:
 	/// Constructor. Define a range of managed VM space.
 	/// \arg start       Starting address of the managed space
 	/// \arg size        Size of the managed space, in bytes
-	/// \arg alloc       Allocator to use for tracking objects
-	vm_space(uintptr_t start, size_t size, kutil::allocator &alloc);
+	vm_space(uintptr_t start, size_t size);
 
 	/// Reserve a section of address space.
 	/// \arg start  Starting address of reservaion, or 0 for any address
@@ -76,8 +74,6 @@ private:
 	node_type * split_out(node_type* node, uintptr_t start, size_t size, vm_state state);
 	node_type * consolidate(node_type* needle);
 
-	slab_allocator<node_type> m_slab;
-	allocator &m_alloc;
 	tree_type m_ranges;
 };
 
diff --git a/src/libraries/kutil/vm_space.cpp b/src/libraries/kutil/vm_space.cpp
index ac576be..a4a996c 100644
--- a/src/libraries/kutil/vm_space.cpp
+++ b/src/libraries/kutil/vm_space.cpp
@@ -8,11 +8,14 @@ namespace kutil {
 using node_type = kutil::avl_node<vm_range>;
 using node_vec = kutil::vector<node_type*>;
 
-vm_space::vm_space(uintptr_t start, size_t size, allocator &alloc) :
-	m_slab(alloc),
-	m_alloc(alloc)
+DEFINE_SLAB_ALLOCATOR(node_type, 1);
+
+vm_space::vm_space(uintptr_t start, size_t size)
 {
-	node_type *node = m_slab.pop();
+	// TODO: replace this with real global ctor
+	slab_allocated<node_type>::hacky_init_remove_me();
+
+	node_type *node = new node_type;
 	node->address = start;
 	node->size = size;
 	node->state = vm_state::none;
@@ -22,9 +25,7 @@ vm_space::vm_space(uintptr_t start, size_t size, allocator &alloc) :
 			start, start+size);
 }
 
-vm_space::vm_space() :
-	m_slab(allocator::invalid),
-	m_alloc(allocator::invalid)
+vm_space::vm_space()
 {
 }
 
@@ -77,7 +78,7 @@ vm_space::split_out(node_type *node, uintptr_t start, size_t size, vm_state stat
 		// Split off rest into new node
 		size_t leading = start - node->address;
 
-		node_type *next = m_slab.pop();
+		node_type *next = new node_type;
 		next->state = state;
 		next->address = start;
 		next->size = node->size - leading;
@@ -100,7 +101,7 @@ vm_space::split_out(node_type *node, uintptr_t start, size_t size, vm_state stat
 		size_t trailing =  node->size - size;
 		node->size -= trailing;
 
-		node_type *next = m_slab.pop();
+		node_type *next = new node_type;
 		next->state = old_state;
 		next->address = node->end();
 		next->size = trailing;
@@ -132,7 +133,7 @@ inline void gather(node_type *node, node_vec &vec)
 node_type *
 vm_space::consolidate(node_type *needle)
 {
-	node_vec nodes(m_ranges.count(), m_alloc);
+	node_vec nodes(m_ranges.count());
 	gather(m_ranges.root(), nodes);
 
 	node_type *prev = nullptr;
@@ -150,7 +151,7 @@ vm_space::consolidate(node_type *needle)
 			prev->size += node->size;
 			if (needle == node)
 				needle = prev;
-			m_ranges.remove(node, m_slab);
+			m_ranges.remove(node);
 		} else {
 			prev = node;
 		}
diff --git a/src/tests/address_manager.cpp b/src/tests/address_manager.cpp
deleted file mode 100644
index 9e7ba65..0000000
--- a/src/tests/address_manager.cpp
+++ /dev/null
@@ -1,78 +0,0 @@
-#include <chrono>
-#include <random>
-#include <vector>
-#include <stddef.h>
-#include <stdlib.h>
-#include <stdint.h>
-
-#include "kutil/address_manager.h"
-#include "kutil/allocator.h"
-#include "catch.hpp"
-
-using namespace kutil;
-
-static const size_t max_block = 1ull << 36;
-static const size_t start = max_block;
-static const size_t GB = 1ull << 30;
-
-class malloc_allocator :
-	public kutil::allocator
-{
-public:
-	virtual void * allocate(size_t n) override { return malloc(n); }
-	virtual void free(void *p) override { free(p); }
-};
-
-TEST_CASE( "Buddy addresses tests", "[address buddy]" )
-{
-	malloc_allocator alloc;
-	address_manager am(alloc);
-	am.add_regions(start, max_block * 2);
-
-	// Blocks should be:
-	// 36: 0-64G, 64-128G
-
-	uintptr_t a = am.allocate(0x400); // under min
-	uintptr_t b = am.allocate(0x400);
-	CHECK( b == a + address_manager::min_alloc);
-
-	am.free(a);
-	am.free(b);
-
-	// Should be back to
-	// 36: 0-64G, 64-128G
-
-	a = am.allocate(max_block);
-	CHECK(a == start);
-	am.free(a);
-
-	// Should be back to
-	// 36: 0-64G, 64-128G
-
-	// This should allocate the 66-68G block, not the
-	// 66-67G block.
-	a = am.mark( start + 66 * GB + 0x1000, GB );
-	CHECK( a == start + 66 * GB );
-
-	// Free blocks should be:
-	// 36: 0-64G
-	// 35: 96-128G
-	// 34: 80-96G
-	// 33: 72-80G
-	// 32: 68-72G
-	// 31: 64-66G
-
-	// This should cause a split of the one 31 block, NOT
-	// be a leftover of the above mark.
-	b = am.allocate(GB);
-	CHECK( b == start + 64 * GB );
-	am.free(b);
-	am.free(a);
-
-	// Should be back to
-	// 36: 0-64G, 64-128G
-	a = am.allocate(max_block);
-	b = am.allocate(max_block);
-	CHECK( b == start + max_block );
-	CHECK( a == start );
-}