From c15189b74b79f9410a34a16180cd44dd3f7db5fc Mon Sep 17 00:00:00 2001
From: Daniel Krebs <github@daniel-krebs.net>
Date: Wed, 16 May 2018 11:25:13 +0200
Subject: [PATCH] common/memory: implement freeing for LinearAllocator

This is still very simple. Only really free memory, when all allocation
have been deallocated so we only need to keep track of the current
number of allocations.
---
 fpga/include/villas/memory.hpp |  1 +
 fpga/lib/common/memory.cpp     | 28 +++++++++++++++++++++-------
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/fpga/include/villas/memory.hpp b/fpga/include/villas/memory.hpp
index b640743fb..a3d5d5dd1 100644
--- a/fpga/include/villas/memory.hpp
+++ b/fpga/include/villas/memory.hpp
@@ -215,6 +215,7 @@ private:
 	size_t nextFreeAddress;	///< next chunk will be allocated here
 	size_t memorySize;		///< total size of managed memory
 	size_t internalOffset;	///< offset in address space (usually 0)
+	size_t allocationCount;	///< Number of individual allocations present
 };
 
 
diff --git a/fpga/lib/common/memory.cpp b/fpga/lib/common/memory.cpp
index 3a44ab63e..fe15e72b1 100644
--- a/fpga/lib/common/memory.cpp
+++ b/fpga/lib/common/memory.cpp
@@ -49,7 +49,8 @@ LinearAllocator::LinearAllocator(MemoryManager::AddressSpaceId memoryAddrSpaceId
     BaseAllocator(memoryAddrSpaceId),
     nextFreeAddress(0),
     memorySize(memorySize),
-    internalOffset(internalOffset)
+    internalOffset(internalOffset),
+    allocationCount(0)
 {
 	// make sure to start at aligned offset, reduce size in case we need padding
 	if(const size_t paddingBytes = getAlignmentPadding(internalOffset)) {
@@ -61,12 +62,20 @@ LinearAllocator::LinearAllocator(MemoryManager::AddressSpaceId memoryAddrSpaceId
 
 	// deallocation callback
 	free = [&](MemoryBlock* mem) {
-		logger->debug("freeing {:#x} bytes at local addr {:#x} (addr space {})",
-		              mem->getSize(), mem->getOffset(), mem->getAddrSpaceId());
-		logger->warn("free() not implemented");
-		logger->debug("available memory: {:#x} bytes", getAvailableMemory());
+		logger->debug("Deallocating memory block at local addr {:#x} (addr space {})",
+		              mem->getOffset(), mem->getAddrSpaceId());
 
 		removeMemoryBlock(*mem);
+
+		allocationCount--;
+		if(allocationCount == 0) {
+			logger->debug("All allocations are deallocated now, freeing memory");
+
+			// all allocations have been deallocated, free all memory
+			nextFreeAddress = 0;
+		}
+
+		logger->debug("Available memory: {:#x} bytes", getAvailableMemory());
 	};
 }
 
@@ -75,8 +84,11 @@ std::string
 LinearAllocator::getName() const
 {
 	std::stringstream name;
-	name << "LinearAlloc" << getAddrSpaceId()
-	     << "@0x" << std::hex << internalOffset;
+	name << "LinearAlloc" << getAddrSpaceId();
+	if(internalOffset != 0) {
+		name << "@0x" << std::hex << internalOffset;
+	}
+
 	return name.str();
 }
 
@@ -122,6 +134,8 @@ LinearAllocator::allocateBlock(size_t size)
 	// mount block into the memory graph
 	insertMemoryBlock(*mem);
 
+	// increase the allocation count
+	allocationCount++;
 
 	return mem;
 }