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mariadb-columnstore-engine/utils/common/poolallocator.h
2017-10-26 17:18:17 +01:00

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2.5 KiB
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/* Copyright (C) 2014 InfiniDB, Inc.
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; version 2 of
the License.
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; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
MA 02110-1301, USA. */
/******************************************************************************************
* $Id$
*
******************************************************************************************/
/* This allocator is an attempt to consolidate small allocations and
deallocations to boost performance and reduce mem fragmentation. */
#ifndef POOLALLOCATOR_H_
#define POOLALLOCATOR_H_
#include <unistd.h>
#include <stdint.h>
#include <vector>
#include <map>
#include <boost/shared_array.hpp>
namespace utils
{
class PoolAllocator
{
public:
static const unsigned DEFAULT_WINDOW_SIZE = 4096 * 40; // should be an integral # of pages
explicit PoolAllocator(unsigned windowSize = DEFAULT_WINDOW_SIZE, bool isTmpSpace = false) :
allocSize(windowSize),
tmpSpace(isTmpSpace),
capacityRemaining(0),
memUsage(0),
nextAlloc(0) { }
PoolAllocator(const PoolAllocator& p) :
allocSize(p.allocSize),
tmpSpace(p.tmpSpace),
capacityRemaining(0),
memUsage(0),
nextAlloc(0) { }
virtual ~PoolAllocator() {}
PoolAllocator& operator=(const PoolAllocator&);
void* allocate(uint64_t size);
void deallocate(void* p);
void deallocateAll();
inline uint64_t getMemUsage() const
{
return memUsage;
}
unsigned getWindowSize() const
{
return allocSize;
}
private:
void newBlock();
unsigned allocSize;
std::vector<boost::shared_array<uint8_t> > mem;
bool tmpSpace;
unsigned capacityRemaining;
uint64_t memUsage;
uint8_t* nextAlloc;
struct OOBMemInfo
{
boost::shared_array<uint8_t> mem;
uint64_t size;
};
typedef std::map<void*, OOBMemInfo> OutOfBandMap;
OutOfBandMap oob; // for mem chunks bigger than the window size; these can be dealloc'd
};
}
#endif