From 13c91d2848938a985ff7ed0969e8037f4f21b8bc Mon Sep 17 00:00:00 2001
From: CTCaer <ctcaer@gmail.com>
Date: Mon, 5 Jan 2026 12:33:31 +0200
Subject: [PATCH] bdk: heap: use ultra fast defragmentation

The defragmentation runs on every free and it only merges subsequent nodes.
So there's no point of looping all nodes.
So, just check if previous and next nodes are mergeable.
This makes free performant and achieves the same exact functionality.
---
 bdk/mem/heap.c | 41 ++++++++++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/bdk/mem/heap.c b/bdk/mem/heap.c
index 8187ffdd..430cf22f 100644
--- a/bdk/mem/heap.c
+++ b/bdk/mem/heap.c
@@ -27,7 +27,7 @@ static void _heap_create(void *start)
 {
 	_heap.start = start;
 	_heap.first = NULL;
-	_heap.last = NULL;
+	_heap.last  = NULL;
 }
 
 // Node info is before node address.
@@ -72,8 +72,8 @@ static void *_heap_alloc(u32 size)
 			// create a new one and set the leftover size.
 			if (new_size >= (sizeof(hnode_t) << 2))
 			{
-				new_node->size = new_size - sizeof(hnode_t);
 				new_node->used = 0;
+				new_node->size = new_size - sizeof(hnode_t);
 				new_node->next = node->next;
 
 				// Check that we are not on first node.
@@ -117,7 +117,7 @@ static void _heap_free(void *addr)
 {
 	hnode_t *node = (hnode_t *)(addr - sizeof(hnode_t));
 
-	// Check if heap owns this node.
+	// Check if heap owns this address.
 	if (addr < _heap.start || node->used != HEAP_USED_MAGIC)
 	{
 		//! BUGPRINTF("free error: addr %08p, used %08X!\n");
@@ -125,24 +125,31 @@ static void _heap_free(void *addr)
 	}
 
 	node->used = 0;
-	node = _heap.first;
 
 #ifndef BDK_MALLOC_NO_DEFRAG
-	// Do simple defragmentation on next blocks.
-	while (node)
+	// Merge with previous node if empty.
+	hnode_t *prev = node->prev;
+	if (prev && !prev->used)
 	{
-		if (!node->used)
-		{
-			if (node->prev && !node->prev->used)
-			{
-				node->prev->size += node->size + sizeof(hnode_t);
-				node->prev->next = node->next;
+		prev->size += node->size + sizeof(hnode_t);
+		prev->next  = node->next;
 
-				if (node->next)
-					node->next->prev = node->prev;
-			}
-		}
-		node = node->next;
+		if (node->next)
+			node->next->prev = prev;
+
+		// Set node to resized one.
+		node = prev;
+	}
+
+	// Merge with next node if empty.
+	hnode_t *next = node->next;
+	if (next && !next->used)
+	{
+		node->size += next->size + sizeof(hnode_t);
+		node->next  = next->next;
+
+		if (next->next)
+			next->next->prev = node;
 	}
 #endif
 }