From 360408871313b682e83c97d98c90659e6bf7d5a6 Mon Sep 17 00:00:00 2001
From: kaetemi <kaetemi@gmail.com>
Date: Wed, 11 Nov 2020 13:42:20 +0800
Subject: [PATCH] Keep a spare memory block in fixed size allocator to avoid
 large allocation overhead on the chunk boundary

---
 nel/include/nel/misc/fixed_size_allocator.h |  1 +
 nel/src/misc/fixed_size_allocator.cpp       | 38 +++++++++++++++------
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/nel/include/nel/misc/fixed_size_allocator.h b/nel/include/nel/misc/fixed_size_allocator.h
index e00809344..1f49dfa68 100644
--- a/nel/include/nel/misc/fixed_size_allocator.h
+++ b/nel/include/nel/misc/fixed_size_allocator.h
@@ -107,6 +107,7 @@ private:
 	uint	_NumBlockPerChunk;
 	//
 	uint	_NumAlloc;
+	uint8	*_SpareMem;
 };
 
 } // NLMISC
diff --git a/nel/src/misc/fixed_size_allocator.cpp b/nel/src/misc/fixed_size_allocator.cpp
index 7a082b8d8..6784aff66 100644
--- a/nel/src/misc/fixed_size_allocator.cpp
+++ b/nel/src/misc/fixed_size_allocator.cpp
@@ -41,6 +41,7 @@ CFixedSizeAllocator::CFixedSizeAllocator(uint numBytesPerBlock, uint numBlockPer
 	nlassert(_NumBytesPerBlock >= numBytesPerBlock);
 	_NumBlockPerChunk = std::max(numBlockPerChunk, (uint) 3);
 	_NumAlloc = 0;
+	_SpareMem = NULL;
 }
 
 // *****************************************************************************************************************
@@ -48,16 +49,22 @@ CFixedSizeAllocator::~CFixedSizeAllocator()
 {
 	if (_NumAlloc != 0)
 	{
-		#ifdef NL_DEBUG
-			nlwarning("%d blocks were not freed", (int) _NumAlloc);
-		#endif
-		return;
+#ifdef NL_DEBUG
+		nlwarning("%d blocks were not freed, leaking memory", (int) _NumAlloc);
+#endif
+	}
+	else
+	{
+		if (_NumChunks > 0)
+		{
+			nlassert(_NumChunks == 1);
+			// delete the left chunk. This should force all the left nodes to be removed from the empty list
+			delete _FreeSpace->Chunk;
+		}
 	}
-	if (_NumChunks > 0)
+	if (_SpareMem)
 	{
-		nlassert(_NumChunks == 1);
-		// delete the left chunk. This should force all the left nodes to be removed from the empty list
-		delete _FreeSpace->Chunk;
+		aligned_free(_SpareMem);
 	}
 }
 
@@ -115,7 +122,10 @@ CFixedSizeAllocator::CChunk::~CChunk()
 	nlassert(NumFreeObjs == 0);
 	nlassert(Allocator->_NumChunks > 0);
 	-- (Allocator->_NumChunks);
-	aligned_free(Mem); //delete[] Mem;
+	if (Allocator->_SpareMem)
+		aligned_free(Mem); //delete[] Mem;
+	else
+		Allocator->_SpareMem = Mem;
 }
 
 // *****************************************************************************************************************
@@ -125,7 +135,15 @@ void CFixedSizeAllocator::CChunk::init(CFixedSizeAllocator *alloc)
 	nlassert(alloc != NULL);
 	Allocator = alloc;
 	//
-	Mem = (uint8 *)aligned_malloc(getBlockSizeWithOverhead() * alloc->getNumBlockPerChunk(), NL_DEFAULT_MEMORY_ALIGNMENT); // new uint8[getBlockSizeWithOverhead() * alloc->getNumBlockPerChunk()];
+	if (Allocator->_SpareMem)
+	{
+		Mem = Allocator->_SpareMem;
+		Allocator->_SpareMem = NULL;
+	}
+	else
+	{
+		Mem = (uint8 *)aligned_malloc(getBlockSizeWithOverhead() * alloc->getNumBlockPerChunk(), NL_DEFAULT_MEMORY_ALIGNMENT); // new uint8[getBlockSizeWithOverhead() * alloc->getNumBlockPerChunk()];
+	}
 	//
 	getNode(0).Chunk = this;
 	getNode(0).Next = &getNode(1);