diff --git a/Common/Vulkan/VulkanContext.h b/Common/Vulkan/VulkanContext.h
index bbe30ced57..ab87a7f5ac 100644
--- a/Common/Vulkan/VulkanContext.h
+++ b/Common/Vulkan/VulkanContext.h
@@ -57,13 +57,12 @@ struct VulkanPhysicalDeviceInfo {
 // This is a bit repetitive...
 class VulkanDeleteList {
 	struct Callback {
-		explicit Callback(void (*f)(void *userdata1, void *userdata2), void *u1, void *u2)
-			: func(f), userdata1(u1), userdata2(u2) {
+		explicit Callback(void (*f)(void *userdata), void *u)
+			: func(f), userdata(u) {
 		}
 
-		void (*func)(void *userdata1, void *userdata2);
-		void *userdata1;
-		void *userdata2;
+		void (*func)(void *userdata);
+		void *userdata;
 	};
 
 public:
@@ -78,7 +77,7 @@ public:
 	void QueueDeletePipelineCache(VkPipelineCache pipelineCache) { pipelineCaches_.push_back(pipelineCache); }
 	void QueueDeleteRenderPass(VkRenderPass renderPass) { renderPasses_.push_back(renderPass); }
 	void QueueDeleteFramebuffer(VkFramebuffer framebuffer) { framebuffers_.push_back(framebuffer); }
-	void QueueCallback(void (*func)(void *userdata1, void *userdata2), void *userdata1, void *userdata2) { callbacks_.push_back(Callback(func, userdata1, userdata2)); }
+	void QueueCallback(void (*func)(void *userdata), void *userdata) { callbacks_.push_back(Callback(func, userdata)); }
 
 	void Take(VulkanDeleteList &del) {
 		assert(descPools_.size() == 0);
@@ -153,7 +152,7 @@ public:
 		}
 		framebuffers_.clear();
 		for (auto &callback : callbacks_) {
-			callback.func(callback.userdata1, callback.userdata2);
+			callback.func(callback.userdata);
 		}
 		callbacks_.clear();
 	}
diff --git a/Common/Vulkan/VulkanMemory.cpp b/Common/Vulkan/VulkanMemory.cpp
index cf7bbb2868..93541c5249 100644
--- a/Common/Vulkan/VulkanMemory.cpp
+++ b/Common/Vulkan/VulkanMemory.cpp
@@ -228,8 +228,8 @@ void VulkanDeviceAllocator::Free(VkDeviceMemory deviceMemory, size_t offset) {
 	}
 
 	// Okay, now enqueue.  It's valid.
-	FreeInfo *info = new FreeInfo(deviceMemory, offset);
-	vulkan_->Delete().QueueCallback(&DispatchFree, this, info);
+	FreeInfo *info = new FreeInfo(this, deviceMemory, offset);
+	vulkan_->Delete().QueueCallback(&DispatchFree, info);
 }
 
 void VulkanDeviceAllocator::ExecuteFree(FreeInfo *userdata) {
diff --git a/Common/Vulkan/VulkanMemory.h b/Common/Vulkan/VulkanMemory.h
index ea0d504c61..186cc8cddd 100644
--- a/Common/Vulkan/VulkanMemory.h
+++ b/Common/Vulkan/VulkanMemory.h
@@ -128,11 +128,18 @@ private:
 	uint8_t *writePtr_;
 };
 
+// VulkanDeviceAllocator
+//
+// Implements a slab based allocator that manages suballocations inside the slabs.
+// Bitmaps are used to handle allocation state, with a 1KB grain.
 class VulkanDeviceAllocator {
 public:
+	// Slab sizes start at minSlabSize and double until maxSlabSize.
+	// Total slab count is unlimited, as long as there's free memory.
 	VulkanDeviceAllocator(VulkanContext *vulkan, size_t minSlabSize, size_t maxSlabSize);
 	~VulkanDeviceAllocator();
 
+	// Requires all memory be free beforehand (including all pending deletes.)
 	void Destroy();
 
 	void Begin() {
@@ -142,7 +149,10 @@ public:
 	void End() {
 	}
 
+	// May return ALLOCATE_FAILED if the allocation fails.
 	size_t Allocate(const VkMemoryRequirements &reqs, VkDeviceMemory *deviceMemory);
+
+	// Crashes on a double or misfree.
 	void Free(VkDeviceMemory deviceMemory, size_t offset);
 
 	static const size_t ALLOCATE_FAILED = -1;
@@ -164,18 +174,18 @@ private:
 	};
 
 	struct FreeInfo {
-		explicit FreeInfo(VkDeviceMemory d, size_t o)
-			: deviceMemory(d), offset(o) {
+		explicit FreeInfo(VulkanDeviceAllocator *a, VkDeviceMemory d, size_t o)
+			: allocator(a), deviceMemory(d), offset(o) {
 		}
 
+		VulkanDeviceAllocator *allocator;
 		VkDeviceMemory deviceMemory;
 		size_t offset;
 	};
 
-	static void DispatchFree(void *thiz, void *userdata) {
-		auto allocator = static_cast<VulkanDeviceAllocator *>(thiz);
+	static void DispatchFree(void *userdata) {
 		auto freeInfo = static_cast<FreeInfo *>(userdata);
-		allocator->ExecuteFree(freeInfo);
+		freeInfo->allocator->ExecuteFree(freeInfo);
 	}
 
 	bool AllocateSlab(size_t minBytes);