Add LocklessAllocator and use it in LocklessList (#2998)

include/AtomicInt.h

@@ -6,20 +6,40 @@
 
 #include <QtCore/QAtomicInt>
 
-#if QT_VERSION >= 0x050000 && QT_VERSION <= 0x050300
+#if QT_VERSION < 0x050300
 
 class AtomicInt : public QAtomicInt
 {
 public:
-	AtomicInt(int value=0) : QAtomicInt(value) {};
+	AtomicInt( int value = 0 ) :
+		QAtomicInt( value )
+	{
+	}
+
+	int fetchAndAndOrdered( int valueToAnd )
+	{
+		int value;
+		do
+		{
+			value = (int)*this;
+		}
+		while( !testAndSetOrdered( value, value & valueToAnd ) );
+		return value;
+	}
+
+#if QT_VERSION >= 0x050000 && QT_VERSION < 0x050300
+	operator int() const
+	{
+		return loadAcquire();
+	}
+#endif
 
-	operator int() const {return loadAcquire();}
 };
 
 #else
 
 typedef QAtomicInt AtomicInt;
 
-#endif // QT_VERSION >= 0x050000 && QT_VERSION <= 0x050300
+#endif // QT_VERSION < 0x050300
 
 #endif

include/LocklessAllocator.h

@@ -0,0 +1,83 @@
+/*
+ * LocklessAllocator.h - allocator with lockless alloc and free
+ *
+ * Copyright (c) 2016 Javier Serrano Polo <javier@jasp.net>
+ *
+ * This file is part of LMMS - http://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef LOCKLESS_ALLOCATOR_H
+#define LOCKLESS_ALLOCATOR_H
+
+#include <stddef.h>
+
+#include "AtomicInt.h"
+
+class LocklessAllocator
+{
+public:
+	LocklessAllocator( size_t nmemb, size_t size );
+	virtual ~LocklessAllocator();
+	void * alloc();
+	void free( void * ptr );
+
+
+private:
+	char * m_pool;
+	size_t m_capacity;
+	size_t m_elementSize;
+
+	AtomicInt * m_freeState;
+	size_t m_freeStateSets;
+
+	AtomicInt m_available;
+	AtomicInt m_startIndex;
+
+} ;
+
+
+
+
+template<typename T>
+class LocklessAllocatorT : private LocklessAllocator
+{
+public:
+	LocklessAllocatorT( size_t nmemb ) :
+		LocklessAllocator( nmemb, sizeof( T ) )
+	{
+	}
+
+	virtual ~LocklessAllocatorT()
+	{
+	}
+
+	T * alloc()
+	{
+		return (T *)LocklessAllocator::alloc();
+	}
+
+	void free( T * ptr )
+	{
+		LocklessAllocator::free( ptr );
+	}
+
+} ;
+
+
+#endif

include/LocklessList.h

@@ -27,6 +27,8 @@
 
 #include <QAtomicPointer>
 
+#include "LocklessAllocator.h"
+
 template<typename T>
 class LocklessList
 {
@@ -37,9 +39,19 @@ class LocklessList
 		Element * next;
 	} ;
 
+	LocklessList( size_t size )
+	{
+		m_allocator = new LocklessAllocatorT<Element>( size );
+	}
+
+	~LocklessList()
+	{
+		delete m_allocator;
+	}
+
 	void push( T value )
 	{
-		Element * e = new Element;
+		Element * e = m_allocator->alloc();
 		e->value = value;
 
 		do
@@ -76,9 +88,15 @@ class LocklessList
 #endif
 	}
 
+	void free( Element * e )
+	{
+		m_allocator->free( e );
+	}
+
 
 private:
 	QAtomicPointer<Element> m_first;
+	LocklessAllocatorT<Element> * m_allocator;
 
 } ;
 

include/PlayHandle.h

@@ -47,6 +47,11 @@ class PlayHandle : public ThreadableJob
 	} ;
 	typedef Types Type;
 
+	enum
+	{
+		MaxNumber = 1024
+	} ;
+
 	PlayHandle( const Type type, f_cnt_t offset = 0 );
 
 	PlayHandle & operator = ( PlayHandle & p )

src/core/CMakeLists.txt

@@ -30,6 +30,7 @@ set(LMMS_SRCS
 	core/LadspaControl.cpp
 	core/LadspaManager.cpp
 	core/LfoController.cpp
+	core/LocklessAllocator.cpp
 	core/MemoryHelper.cpp
 	core/MemoryManager.cpp
 	core/MeterModel.cpp

src/core/LocklessAllocator.cpp

@@ -0,0 +1,159 @@
+/*
+ * LocklessAllocator.cpp - allocator with lockless alloc and free
+ *
+ * Copyright (c) 2016 Javier Serrano Polo <javier@jasp.net>
+ *
+ * This file is part of LMMS - http://lmms.io
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include "LocklessAllocator.h"
+
+#include <stdio.h>
+#include <strings.h>
+
+#include "lmmsconfig.h"
+
+
+static const size_t SIZEOF_SET = sizeof( int ) * 8;
+
+
+static size_t align( size_t size, size_t alignment )
+{
+	size_t misalignment = size % alignment;
+	if( misalignment )
+	{
+		size += alignment - misalignment;
+	}
+	return size;
+}
+
+
+
+
+LocklessAllocator::LocklessAllocator( size_t nmemb, size_t size )
+{
+	m_capacity = align( nmemb, SIZEOF_SET );
+	m_elementSize = align( size, sizeof( void * ) );
+	m_pool = new char[m_capacity * m_elementSize];
+
+	m_freeStateSets = m_capacity / SIZEOF_SET;
+	m_freeState = new AtomicInt[m_freeStateSets];
+
+	m_available = m_capacity;
+}
+
+
+
+
+LocklessAllocator::~LocklessAllocator()
+{
+	int available = m_available;
+	if( available != m_capacity )
+	{
+		fprintf( stderr, "LocklessAllocator: "
+				"Destroying with elements still allocated\n" );
+	}
+
+	delete[] m_pool;
+	delete[] m_freeState;
+}
+
+
+
+
+#ifdef LMMS_BUILD_WIN32
+static int ffs( int i )
+{
+	if( !i )
+	{
+		return 0;
+	}
+	for( int j = 0;; )
+	{
+		if( i & 1 << j++ )
+		{
+			return j;
+		}
+	}
+}
+#endif
+
+
+
+
+void * LocklessAllocator::alloc()
+{
+	int available;
+	do
+	{
+		available = m_available;
+		if( !available )
+		{
+			fprintf( stderr, "LocklessAllocator: No free space\n" );
+			return NULL;
+		}
+	}
+	while( !m_available.testAndSetOrdered( available, available - 1 ) );
+
+	size_t startIndex = m_startIndex.fetchAndAddOrdered( 1 )
+							% m_freeStateSets;
+	for( size_t set = startIndex;; set = ( set + 1 ) % m_freeStateSets )
+	{
+		for( int freeState = m_freeState[set]; freeState != -1;
+						freeState = m_freeState[set] )
+		{
+			int bit = ffs( ~freeState ) - 1;
+			if( m_freeState[set].testAndSetOrdered( freeState,
+							freeState | 1 << bit ) )
+			{
+				return m_pool + ( SIZEOF_SET * set + bit )
+								* m_elementSize;
+			}
+		}
+	}
+}
+
+
+
+
+void LocklessAllocator::free( void * ptr )
+{
+	ptrdiff_t diff = (char *)ptr - m_pool;
+	if( diff < 0 || diff % m_elementSize )
+	{
+invalid:
+		fprintf( stderr, "LocklessAllocator: Invalid pointer\n" );
+		return;
+	}
+	size_t offset = diff / m_elementSize;
+	if( offset >= m_capacity )
+	{
+		goto invalid;
+	}
+	size_t set = offset / SIZEOF_SET;
+	int bit = offset % SIZEOF_SET;
+	int mask = 1 << bit;
+	int prevState = m_freeState[set].fetchAndAndOrdered( ~mask );
+	if ( !( prevState & mask ) )
+	{
+		fprintf( stderr, "LocklessAllocator: Block not in use\n" );
+		return;
+	}
+	m_available.fetchAndAddOrdered( 1 );
+}

src/core/Mixer.cpp

@@ -77,6 +77,7 @@ Mixer::Mixer( bool renderOnly ) :
 	m_writeBuf( NULL ),
 	m_workers(),
 	m_numWorkers( QThread::idealThreadCount()-1 ),
+	m_newPlayHandles( PlayHandle::MaxNumber ),
 	m_qualitySettings( qualitySettings::Mode_Draft ),
 	m_masterGain( 1.0f ),
 	m_isProcessing( false ),
@@ -419,7 +420,7 @@ const surroundSampleFrame * Mixer::renderNextBuffer()
 	{
 		m_playHandles += e->value;
 		LocklessListElement * next = e->next;
-		delete e;
+		m_newPlayHandles.free( e );
 		e = next;
 	}
 
@@ -683,7 +684,7 @@ void Mixer::removePlayHandle( PlayHandle * _ph )
 				{
 					m_newPlayHandles.setFirst( e->next );
 				}
-				delete e;
+				m_newPlayHandles.free( e );
 				removedFromList = true;
 				break;
 			}