m::memory::LinearAllocator Struct Reference

This is the simplest kind of allocator. More...

#include <memory.hpp>

Inheritance diagram for m::memory::LinearAllocator:

Collaboration diagram for m::memory::LinearAllocator:

Public Member Functions
	LinearAllocator ()
	~LinearAllocator ()
Memory	allocate (std::size_t size) override
	Creates a new memory object with size bytes of freshly allocated memory.
std::size_t	offset () const
	Returns the offset in the underlying memory file where the next allocation is placed.
int	fd () const
	Return the file descriptor of the underlying memory file.

Protected Member Functions
Memory	create_memory (void *addr, std::size_t size, std::size_t offset)
	Helper method to inherit the friend ability to construct a Memory object.

Private Member Functions
void	deallocate (Memory &&mem) override
	Deallocates a memory object.

Private Attributes
std::size_t	offset_ = 0
	the offset from the start of the memory file of the next allocation
std::vector< std::size_t >	allocations_
	‍stack of allocations; allocations can be marked deallocated for later reclaiming
int	fd_
	file descriptor of the underlying memory file

Detailed Description

This is the simplest kind of allocator.

The idea is to keep a pointer at the first memory address of your memory chunk and move it every time an allocation is done. In this allocator, the internal fragmentation is kept to a minimum because all elements are sequentially inserted and the only fragmentation between them is the alignment. Note that allocations are always page aligned and whole multiples of an entire page. There is no overhead to allocation and existing allocations are never modified. Deallocation can only reclaim memory if all chronologically later allocations have been deallocated before. If possible, deallocate memory in the inverse order of allocation.

Definition at line 138 of file memory.hpp.

Constructor & Destructor Documentation

LinearAllocator()

m::memory::LinearAllocator::LinearAllocator ( )

inline

Definition at line 147 of file memory.hpp.

~LinearAllocator()

m::memory::LinearAllocator::~LinearAllocator ( )

inline

Definition at line 148 of file memory.hpp.

Member Function Documentation

allocate()

M_LCOV_EXCL_STOP Memory LinearAllocator::allocate ( std::size_t  size )

overridevirtual

Creates a new memory object with size bytes of freshly allocated memory.

Implements m::memory::Allocator.

Definition at line 120 of file memory.cpp.

References allocations_, m::Ceil_To_Next_Page(), m::memory::Allocator::create_memory(), m::memory::Allocator::fd(), m::Is_Page_Aligned(), M_insist, m::memory::Allocator::Memory, and offset_.

Referenced by m::ColumnStore::ColumnStore(), m::PaxStore::PaxStore(), and m::RowStore::RowStore().

create_memory()

Memory Allocator::create_memory ( void *  addr, std::size_t  size, std::size_t  offset  )

protectedinherited

Helper method to inherit the friend ability to construct a Memory object.

Definition at line 50 of file memory.cpp.

References m::memory::Allocator::Memory.

Referenced by allocate().

deallocate()

void LinearAllocator::deallocate ( Memory &&  mem )

overrideprivatevirtual

Deallocates a memory object.

Implements m::memory::Allocator.

Definition at line 162 of file memory.cpp.

References allocations_, m::and, m::memory::Allocator::fd(), M_insist, and offset_.

fd()

int m::memory::Allocator::fd ( ) const

inlineinherited

Return the file descriptor of the underlying memory file.

Definition at line 29 of file memory.hpp.

Referenced by allocate(), deallocate(), and m::memory::Memory::dump().

offset()

std::size_t m::memory::LinearAllocator::offset ( ) const

inline

Returns the offset in the underlying memory file where the next allocation is placed.

Definition at line 153 of file memory.hpp.

Field Documentation

allocations_

std::vector<std::size_t> m::memory::LinearAllocator::allocations_

private

‍stack of allocations; allocations can be marked deallocated for later reclaiming

Definition at line 144 of file memory.hpp.

Referenced by allocate(), and deallocate().

fd_

int m::memory::Allocator::fd_

privateinherited

file descriptor of the underlying memory file

Definition at line 22 of file memory.hpp.

Referenced by m::memory::Allocator::Allocator(), and m::memory::Allocator::~Allocator().

offset_

std::size_t m::memory::LinearAllocator::offset_ = 0

private

the offset from the start of the memory file of the next allocation

Definition at line 141 of file memory.hpp.

Referenced by allocate(), and deallocate().

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The documentation for this struct was generated from the following files:

• include/mutable/util/memory.hpp
• src/util/memory.cpp