slab_allocator.hpp (4102B)
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/* Relacy Race Detector
* Copyright (c) 2008-2010, Dmitry S. Vyukov
* All rights reserved.
* This software is provided AS-IS with no warranty, either express or implied.
* This software is distributed under a license and may not be copied,
* modified or distributed except as expressly authorized under the
* terms of the license contained in the file LICENSE.TXT in this distribution.
*/
#ifndef RL_SLAB_ALLOCATOR_HPP
#define RL_SLAB_ALLOCATOR_HPP
#ifdef _MSC_VER
# pragma once
#endif
#include "base.hpp"
namespace rl
{
template<typename type>
class slab_allocator : nocopy<>
{
public:
slab_allocator()
: freelist_()
, blocks_()
, alloc_count_()
{
}
~slab_allocator()
{
char* pos = blocks_;
while (pos)
{
char* const next = *reinterpret_cast<char**>(pos);
::free(pos);
pos = next;
}
}
type* alloc(void* ctx = 0)
{
if (freelist_)
{
type* p = freelist_;
freelist_ = *reinterpret_cast<type**>(p);
alloc_count_ += 1;
*(void**)p = ctx;
type* pp = reinterpret_cast<type*>((reinterpret_cast<void**>(p) + 1));
return pp;
}
else
{
return alloc_batch();
}
}
void free(type* p)
{
type** pos = reinterpret_cast<type**>((reinterpret_cast<void**>(p) - 1));
pos[0] = freelist_;
freelist_ = reinterpret_cast<type*>(pos);
alloc_count_ -= 1;
}
bool iteration_end()
{
#ifndef RL_GC
return alloc_count_ == 0;
#else
freelist_ = 0;
size_t elem_size = sizeof(void*) + sizeof(type);
elem_size = (elem_size + 15) & ~15;
char* pos = blocks_;
while (pos)
{
char* p = pos;
p += elem_size;
for (size_t i = 0; i != batch_size; ++i)
{
*reinterpret_cast<type**>(p) = freelist_;
freelist_ = reinterpret_cast<type*>(p);
p += elem_size;
}
pos = *reinterpret_cast<char**>(pos);
}
return true;
#endif
}
void output_allocs(std::ostream& stream)
{
size_t elem_size = sizeof(void*) + sizeof(type);
elem_size = (elem_size + 15) & ~15;
set<void*>::type allocs;
char* pos = blocks_;
while (pos)
{
char* p = pos;
p += elem_size;
for (size_t i = 0; i != batch_size; ++i)
{
allocs.insert(p);
p += elem_size;
}
pos = *reinterpret_cast<char**>(pos);
}
set<void*>::type avail;
type* pos2 = freelist_;
while (pos2)
{
avail.insert(pos2);
pos2 = *reinterpret_cast<type**>(pos2);
}
vector<void*>::type diff;
std::set_difference(allocs.begin(), allocs.end(), avail.begin(), avail.end(), std::back_inserter(diff));
for (size_t i = 0; i != diff.size(); ++i)
{
stream << *(void**)diff[i] << std::endl;
}
}
private:
static size_t const batch_size = 128;
type* freelist_;
char* blocks_;
size_t alloc_count_;
RL_NOINLINE type* alloc_batch()
{
size_t elem_size = sizeof(void*) + sizeof(type);
elem_size = (elem_size + 15) & ~15;
char* const batch = (char*)(::malloc)(elem_size * (batch_size + 1));
if (0 == batch)
throw std::bad_alloc();
*reinterpret_cast<char**>(batch) = blocks_;
blocks_ = batch;
char* p = batch;
p += elem_size;
for (size_t i = 0; i != batch_size; ++i)
{
*reinterpret_cast<type**>(p) = freelist_;
freelist_ = reinterpret_cast<type*>(p);
p += elem_size;
}
return alloc();
}
};
}
#endif
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