diff --git a/src/kernel/apic.cpp b/src/kernel/apic.cpp
index d56d500..fc7dd69 100644
--- a/src/kernel/apic.cpp
+++ b/src/kernel/apic.cpp
@@ -1,8 +1,8 @@
+#include "kutil/assert.h"
 #include "apic.h"
-#include "assert.h"
 #include "interrupts.h"
 #include "log.h"
-#include "memory_pages.h"
+#include "page_manager.h"
 
 
 static uint32_t
diff --git a/src/kernel/assert.cpp b/src/kernel/assert.cpp
index 66ad5ed..4f0dd38 100644
--- a/src/kernel/assert.cpp
+++ b/src/kernel/assert.cpp
@@ -1,4 +1,4 @@
-#include "assert.h"
+#include "kutil/assert.h"
 #include "console.h"
 
 [[noreturn]] void
diff --git a/src/kernel/assert.h b/src/kernel/assert.h
deleted file mode 100644
index 1019d28..0000000
--- a/src/kernel/assert.h
+++ /dev/null
@@ -1,5 +0,0 @@
-#pragma once
-
-[[noreturn]] void __kernel_assert(const char *file, unsigned line, const char *message);
-
-#define kassert(stmt, message)  if(!(stmt)) { __kernel_assert(__FILE__, __LINE__, (message)); } else {}
diff --git a/src/kernel/device_manager.cpp b/src/kernel/device_manager.cpp
index 5b2b07d..1b98c11 100644
--- a/src/kernel/device_manager.cpp
+++ b/src/kernel/device_manager.cpp
@@ -1,15 +1,15 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "kutil/assert.h"
 #include "kutil/memory.h"
 #include "acpi_tables.h"
 #include "apic.h"
-#include "assert.h"
 #include "device_manager.h"
 #include "interrupts.h"
 #include "log.h"
 #include "memory.h"
-#include "memory_pages.h"
+#include "page_manager.h"
 
 static const char expected_signature[] = "RSD PTR ";
 
diff --git a/src/kernel/font.cpp b/src/kernel/font.cpp
index de571be..e5320eb 100644
--- a/src/kernel/font.cpp
+++ b/src/kernel/font.cpp
@@ -1,4 +1,4 @@
-#include "assert.h"
+#include "kutil/assert.h"
 #include "font.h"
 
 /* PSF2 header format
diff --git a/src/kernel/interrupts.cpp b/src/kernel/interrupts.cpp
index 9788be3..b03fd06 100644
--- a/src/kernel/interrupts.cpp
+++ b/src/kernel/interrupts.cpp
@@ -7,7 +7,7 @@
 #include "interrupts.h"
 #include "io.h"
 #include "log.h"
-#include "memory_pages.h"
+#include "page_manager.h"
 
 enum class gdt_flags : uint8_t
 {
diff --git a/src/kernel/kalloc.cpp b/src/kernel/kalloc.cpp
new file mode 100644
index 0000000..af23047
--- /dev/null
+++ b/src/kernel/kalloc.cpp
@@ -0,0 +1,10 @@
+#include "kutil/memory_manager.h"
+
+kutil::memory_manager g_kernel_memory_manager;
+
+void * kalloc(size_t length) { return g_kernel_memory_manager.allocate(length); }
+void kfree(void *p) { g_kernel_memory_manager.free(p); }
+void * operator new (size_t n)    { return g_kernel_memory_manager.allocate(n); }
+void * operator new[] (size_t n)  { return g_kernel_memory_manager.allocate(n); }
+void operator delete (void *p)  { return g_kernel_memory_manager.free(p); }
+void operator delete[] (void *p){ return g_kernel_memory_manager.free(p); }
diff --git a/src/kernel/kalloc.h b/src/kernel/kalloc.h
new file mode 100644
index 0000000..e45eaed
--- /dev/null
+++ b/src/kernel/kalloc.h
@@ -0,0 +1,17 @@
+#pragma once
+/// \file kalloc.h
+/// Definitions of kalloc() and kfree()
+
+#include <stddef.h>
+
+
+/// Allocate kernel space memory.
+/// \arg length  The amount of memory to allocate, in bytes
+/// \returns     A pointer to the allocated memory, or nullptr if
+///              allocation failed.
+inline void * kalloc(size_t length);
+
+/// Free kernel space memory.
+/// \arg p   The pointer to free
+inline void kfree(void *p);
+
diff --git a/src/kernel/log.cpp b/src/kernel/log.cpp
index a393e82..c1b6231 100644
--- a/src/kernel/log.cpp
+++ b/src/kernel/log.cpp
@@ -1,6 +1,6 @@
 #include <type_traits>
+#include "kutil/assert.h"
 #include "kutil/memory.h"
-#include "assert.h"
 #include "console.h"
 #include "log.h"
 
diff --git a/src/kernel/main.cpp b/src/kernel/main.cpp
index bb716ba..375cda5 100644
--- a/src/kernel/main.cpp
+++ b/src/kernel/main.cpp
@@ -1,6 +1,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "kutil/assert.h"
 #include "kutil/memory.h"
 #include "console.h"
 #include "cpu.h"
@@ -11,7 +12,7 @@
 #include "kernel_data.h"
 #include "log.h"
 #include "memory.h"
-#include "memory_pages.h"
+#include "page_manager.h"
 #include "screen.h"
 #include "serial.h"
 
@@ -22,6 +23,9 @@ extern "C" {
 	void *__bss_start, *__bss_end;
 }
 
+extern [[noreturn]] void
+__kernel_assert(const char *file, unsigned line, const char *message);
+
 void
 init_console(const popcorn_data *header)
 {
@@ -58,9 +62,11 @@ void do_error_1() { do_error_2(); }
 void
 kernel_main(popcorn_data *header)
 {
+	kutil::assert_set_callback(__kernel_assert);
+
 	page_manager *pager = new (&g_page_manager) page_manager;
 
-	memory_initialize_managers(
+	memory_initialize(
 			header->memory_map,
 			header->memory_map_length,
 			header->memory_map_desc_size);
diff --git a/src/kernel/memory_bootstrap.cpp b/src/kernel/memory_bootstrap.cpp
index 077a9dc..7c3297f 100644
--- a/src/kernel/memory_bootstrap.cpp
+++ b/src/kernel/memory_bootstrap.cpp
@@ -1,7 +1,7 @@
+#include "kutil/assert.h"
 #include "kutil/memory.h"
-#include "assert.h"
 #include "memory.h"
-#include "memory_pages.h"
+#include "page_manager.h"
 
 const unsigned efi_page_size = 0x1000;
 
@@ -407,7 +407,7 @@ page_in_ident(
 }
 
 void
-memory_initialize_managers(const void *memory_map, size_t map_length, size_t desc_length)
+memory_initialize(const void *memory_map, size_t map_length, size_t desc_length)
 {
 	// The bootloader reserved 16 pages for page tables, which we'll use to bootstrap.
 	// The first one is the already-installed PML4, so grab it from CR3.
diff --git a/src/kernel/memory_pages.cpp b/src/kernel/page_manager.cpp
similarity index 95%
rename from src/kernel/memory_pages.cpp
rename to src/kernel/page_manager.cpp
index f2030dd..469f762 100644
--- a/src/kernel/memory_pages.cpp
+++ b/src/kernel/page_manager.cpp
@@ -1,14 +1,12 @@
 #include <algorithm>
 
-#include "assert.h"
+#include "kutil/assert.h"
+#include "kutil/memory_manager.h"
 #include "log.h"
-#include "memory.h"
-#include "memory_pages.h"
+#include "page_manager.h"
 
 page_manager g_page_manager;
 
-using addr_t = page_manager::addr_t;
-
 
 static addr_t
 pt_to_phys(page_table *pt)
@@ -16,6 +14,7 @@ pt_to_phys(page_table *pt)
 	return reinterpret_cast<addr_t>(pt) - page_manager::page_offset;
 }
 
+
 static page_table *
 pt_from_phys(addr_t p)
 {
@@ -29,6 +28,18 @@ struct free_page_header
 	size_t count;
 };
 
+
+void mm_grow_callback(void *next, size_t length)
+{
+	kassert(length % page_manager::page_size == 0,
+			"Heap manager requested a fractional page.");
+
+	size_t pages = length / page_manager::page_size;
+	log::info(logs::memory, "Heap manager growing heap by %d pages.", pages);
+	g_page_manager.map_pages(reinterpret_cast<addr_t>(next), pages);
+}
+
+
 size_t
 page_block::length(page_block *list)
 {
@@ -203,7 +214,10 @@ page_manager::init(
 		}
 	}
 
-	new (&g_kernel_memory_manager) memory_manager(reinterpret_cast<void *>(end));
+	extern kutil::memory_manager g_kernel_memory_manager;
+	new (&g_kernel_memory_manager) kutil::memory_manager(
+			reinterpret_cast<void *>(end),
+			mm_grow_callback);
 }
 
 void
diff --git a/src/kernel/memory_pages.h b/src/kernel/page_manager.h
similarity index 97%
rename from src/kernel/memory_pages.h
rename to src/kernel/page_manager.h
index cb94804..508fc8d 100644
--- a/src/kernel/memory_pages.h
+++ b/src/kernel/page_manager.h
@@ -1,10 +1,11 @@
 #pragma once
-/// \file memory_pages.h
+/// \file page_manager.h
 /// The page memory manager and related definitions.
 
 #include <stddef.h>
 #include <stdint.h>
 
+#include "kutil/memory.h"
 #include "kutil/enum_bitfields.h"
 
 struct page_block;
@@ -16,8 +17,6 @@ struct free_page_header;
 class page_manager
 {
 public:
-	using addr_t = uint64_t;
-
 	/// Size of a single page.
 	static const size_t page_size = 0x1000;
 
@@ -53,8 +52,6 @@ public:
 	static page_manager * get();
 
 private:
-	friend void memory_initialize_managers(const void *, size_t, size_t);
-
 	/// Set up the memory manager from bootstraped memory
 	void init(
 			page_block *free,
@@ -143,6 +140,7 @@ private:
 	page_block *m_block_cache; ///< Cache of unused page_block structs
 	free_page_header *m_page_cache; ///< Cache of free pages to use for tables
 
+	friend void memory_initialize(const void *, size_t, size_t);
 	page_manager(const page_manager &) = delete;
 };
 
@@ -175,8 +173,6 @@ IS_BITFIELD(page_block_flags);
 /// linked list of such structures.
 struct page_block
 {
-	using addr_t = page_manager::addr_t;
-
 	addr_t physical_address;
 	addr_t virtual_address;
 	uint32_t count;
@@ -294,3 +290,6 @@ template <typename T> inline T page_align(T p)
 /// \returns  The next page-table-aligned address _after_ `p`.
 template <typename T> inline T page_table_align(T p) { return ((p - 1) & ~0x1fffffull) + 0x200000; }
 
+
+/// Bootstrap the memory managers.
+void memory_initialize(const void *memory_map, size_t map_length, size_t desc_length);
diff --git a/src/modules/kutil/assert.cpp b/src/modules/kutil/assert.cpp
new file mode 100644
index 0000000..c02907c
--- /dev/null
+++ b/src/modules/kutil/assert.cpp
@@ -0,0 +1,16 @@
+#include "assert.h"
+
+namespace kutil {
+
+assert_callback __kernel_assert_p = nullptr;
+
+assert_callback
+assert_set_callback(assert_callback f)
+{
+	assert_callback old = __kernel_assert_p;
+	__kernel_assert_p = f;
+	return old;
+}
+
+
+} // namespace kutil
diff --git a/src/modules/kutil/assert.h b/src/modules/kutil/assert.h
new file mode 100644
index 0000000..aceaea6
--- /dev/null
+++ b/src/modules/kutil/assert.h
@@ -0,0 +1,19 @@
+#pragma once
+
+namespace kutil {
+
+using assert_callback =
+	[[noreturn]] void (*)
+	(const char *file, unsigned line, const char *message);
+
+/// Set the global kernel assert callback
+/// \args f   The new callback
+/// \returns  The old callback
+assert_callback assert_set_callback(assert_callback f);
+
+extern assert_callback __kernel_assert_p;
+
+} // namespace kutil
+
+
+#define kassert(stmt, message)  if(!(stmt)) { ::kutil::__kernel_assert_p(__FILE__, __LINE__, (message)); } else {}
diff --git a/src/modules/kutil/memory.cpp b/src/modules/kutil/memory.cpp
index 8ad1d5f..617daa0 100644
--- a/src/modules/kutil/memory.cpp
+++ b/src/modules/kutil/memory.cpp
@@ -1,5 +1,7 @@
 #include "memory.h"
 
+void * operator new (size_t, void *p) { return p; }
+
 namespace kutil {
 
 void *
diff --git a/src/modules/kutil/memory.h b/src/modules/kutil/memory.h
index b94b5d4..9c4663d 100644
--- a/src/modules/kutil/memory.h
+++ b/src/modules/kutil/memory.h
@@ -5,6 +5,8 @@
 
 
 using addr_t = uint64_t;
+void * operator new (size_t, void *p);
+
 
 namespace kutil {
 
diff --git a/src/kernel/memory.cpp b/src/modules/kutil/memory_manager.cpp
similarity index 68%
rename from src/kernel/memory.cpp
rename to src/modules/kutil/memory_manager.cpp
index 37f33d3..5646d2d 100644
--- a/src/kernel/memory.cpp
+++ b/src/modules/kutil/memory_manager.cpp
@@ -1,11 +1,10 @@
-#include "kutil/enum_bitfields.h"
-#include "kutil/memory.h"
+#include <stdint.h>
 #include "assert.h"
-#include "log.h"
 #include "memory.h"
-#include "memory_pages.h"
+#include "memory_manager.h"
+
+namespace kutil {
 
-memory_manager g_kernel_memory_manager;
 
 struct memory_manager::mem_header
 {
@@ -70,14 +69,16 @@ private:
 
 memory_manager::memory_manager() :
 	m_start(nullptr),
-	m_length(0)
+	m_length(0),
+	m_grow(nullptr)
 {
 	kutil::memset(m_free, 0, sizeof(m_free));
 }
 
-memory_manager::memory_manager(void *start) :
+memory_manager::memory_manager(void *start, grow_callback grow_cb) :
 	m_start(start),
-	m_length(0)
+	m_length(0),
+	m_grow(grow_cb)
 {
 	kutil::memset(m_free, 0, sizeof(m_free));
 	grow_memory();
@@ -89,13 +90,10 @@ memory_manager::allocate(size_t length)
 	size_t total = length + sizeof(mem_header);
 	unsigned size = min_size;
 	while (total > (1 << size)) size++;
-	kassert(size < max_size, "Tried to allocate a block bigger than max_size");
-	log::debug(logs::memory, "Allocating %d bytes, which is size %d", total, size);
+	kassert(size <= max_size, "Tried to allocate a block bigger than max_size");
 
 	mem_header *header = pop_free(size);
 	header->set_used(true);
-
-	log::debug(logs::memory, "  Returning %d bytes at %lx", length, header + 1);
 	return header + 1;
 }
 
@@ -106,16 +104,12 @@ memory_manager::free(void *p)
 	header -= 1; // p points after the header
 	header->set_used(false);
 
-	log::debug(logs::memory, "Freeing a block of size %2d at %lx", header->size(), header);
-
 	while (true) {
 		mem_header *buddy = header->buddy();
 		if (buddy->used() || buddy->size() != header->size()) break;
-		log::debug(logs::memory, "  buddy is same size at %lx", buddy);
 		buddy->remove();
 		header = header->eldest() ? header : buddy;
 		header->set_size(header->size() + 1);
-		log::debug(logs::memory, "  joined into size %2d at %lx", header->size(), header);
 	}
 
 	uint8_t size = header->size();
@@ -131,19 +125,14 @@ memory_manager::grow_memory()
 	size_t length = (1 << max_size);
 
 	void *next = kutil::offset_pointer(m_start, m_length);
-
-	g_page_manager.map_pages(
-			reinterpret_cast<page_manager::addr_t>(next),
-			length / page_manager::page_size);
+	kassert(m_grow, "Tried to grow heap without a growth callback");
+	m_grow(next, length);
 
 	mem_header *block = new (next) mem_header(nullptr, get_free(max_size), max_size);
 	get_free(max_size) = block;
 	if (block->next())
 		block->next()->set_prev(block);
 	m_length += length;
-
-	log::debug(logs::memory, "Allocated new block at %lx: size %d next %lx",
-			block, max_size, block->next());
 }
 
 void
@@ -163,10 +152,6 @@ memory_manager::ensure_block(unsigned size)
 	orig->set_next(next);
 	orig->set_size(size);
 	get_free(size) = orig;
-
-	log::debug(logs::memory, "ensure_block[%2d] split blocks:", size);
-	log::debug(logs::memory, "   %lx: size %d next %lx", orig, size, orig->next());
-	log::debug(logs::memory, "   %lx: size %d next %lx", next, size, next->next());
 }
 
 memory_manager::mem_header *
@@ -180,8 +165,4 @@ memory_manager::pop_free(unsigned size)
 	return block;
 }
 
-void * operator new (size_t, void *p) { return p; }
-void * operator new (size_t n)    { return g_kernel_memory_manager.allocate(n); }
-void * operator new[] (size_t n)  { return g_kernel_memory_manager.allocate(n); }
-void operator delete (void *p)  { return g_kernel_memory_manager.free(p); }
-void operator delete[] (void *p){ return g_kernel_memory_manager.free(p); }
+} // namespace kutil
diff --git a/src/kernel/memory.h b/src/modules/kutil/memory_manager.h
similarity index 62%
rename from src/kernel/memory.h
rename to src/modules/kutil/memory_manager.h
index eb028c9..632119c 100644
--- a/src/kernel/memory.h
+++ b/src/modules/kutil/memory_manager.h
@@ -1,17 +1,25 @@
 #pragma once
-/// \file memory.h
-/// The block memory manager and related definitions.
+/// \file memory_manager.h
+/// A buddy allocator and related definitions.
 
 #include <stddef.h>
-#include <stdint.h>
+
+namespace kutil {
 
 
 /// Manager for allocation of virtual memory.
 class memory_manager
 {
 public:
+	using grow_callback = void (*)(void *start, size_t length);
+
+	/// Default constructor. Creates an invalid manager.
 	memory_manager();
-	memory_manager(void *start);
+
+	/// Constructor.
+	/// \arg start    Pointer to the start of the heap to be managed
+	/// \arg grow_cb  Function pointer to grow the heap size
+	memory_manager(void *start, grow_callback grow_cb);
 
 	/// Allocate memory from the area managed.
 	/// \arg length  The amount of memory to allocate, in bytes
@@ -23,6 +31,7 @@ public:
 	/// \arg p  A pointer previously retuned by allocate()
 	void free(void *p);
 
+
 private:
 	class mem_header;
 
@@ -49,23 +58,9 @@ private:
 	void *m_start;
 	size_t m_length;
 
-	friend class page_manager;
+	grow_callback m_grow;
+
 	memory_manager(const memory_manager &) = delete;
 };
 
-extern memory_manager g_kernel_memory_manager;
-
-/// Bootstrap the memory managers.
-void memory_initialize_managers(const void *memory_map, size_t map_length, size_t desc_length);
-
-/// Allocate kernel space memory.
-/// \arg length  The amount of memory to allocate, in bytes
-/// \returns     A pointer to the allocated memory, or nullptr if
-///              allocation failed.
-inline void * kalloc(size_t length) { return g_kernel_memory_manager.allocate(length); }
-
-/// Free kernel space memory.
-/// \arg p   The pointer to free
-inline void kfree(void *p) { g_kernel_memory_manager.free(p); }
-
-void * operator new (size_t, void *p);
+} // namespace kutil