pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets > Class Template Reference

#include <buddy_allocator.h>

Inheritance diagram for pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets >:

Public Types
using	BucketType = internal::GenericBuddyAllocator::BucketType
Public Types inherited from pw::Deallocator
using	Capabilities = allocator::Capabilities
using	Capability = allocator::Capability
using	Layout = allocator::Layout

Public Member Functions
	BuddyAllocator ()
	Constructs an allocator. Callers must call Init.
	BuddyAllocator (ByteSpan region)
void	Init (ByteSpan region)
Public Member Functions inherited from pw::Allocator
void *	Allocate (Layout layout)
template<typename T , int &... kExplicitGuard, typename... Args>
std::enable_if_t<!std::is_array_v< T >, T * >	New (Args &&... args)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
ElementType *	New (size_t count)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
ElementType *	New (size_t count, size_t alignment)
template<typename T >
T *	NewArray (size_t count)
template<typename T >
T *	NewArray (size_t count, size_t alignment)
template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0, typename... Args>
UniquePtr< T >	MakeUnique (Args &&... args)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique (size_t size)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	MakeUnique (size_t size, size_t alignment)
template<typename T >
UniquePtr< T[]>	MakeUniqueArray (size_t size)
template<typename T >
UniquePtr< T[]>	MakeUniqueArray (size_t size, size_t alignment)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0, typename... Args>
void	MakeUnique (Args &&...)=delete
template<typename T , int &... kExplicitGuard, std::enable_if_t<!std::is_array_v< T >, int > = 0, typename... Args>
SharedPtr< T >	MakeShared (Args &&... args)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared (size_t size)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
SharedPtr< T >	MakeShared (size_t size, size_t alignment)
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0, typename... Args>
std::enable_if_t< is_bounded_array_v< T > >	MakeShared (Args &&...)=delete
bool	Resize (void *ptr, size_t new_size)
bool	Resize (void *ptr, Layout layout, size_t new_size)
void *	Reallocate (void *ptr, Layout new_layout)
void *	Reallocate (void *ptr, Layout old_layout, size_t new_size)
size_t	GetAllocated () const
Public Member Functions inherited from pw::Deallocator
constexpr const Capabilities &	capabilities () const
bool	HasCapability (Capability capability) const
	Returns whether a given capabilityis enabled for this object.
void	Deallocate (void *ptr)
void	Deallocate (void *ptr, Layout layout)
template<typename T >
void	Delete (T *ptr)
StatusWithSize	GetCapacity () const
bool	IsEqual (const Deallocator &other) const
template<typename T , int &... kExplicitGuard, std::enable_if_t< is_bounded_array_v< T >, int > = 0, typename... Args>
void	WrapUnique (Args &&...)=delete

Static Public Attributes
static constexpr size_t	kMinOuterSize = kMinOuterSize_

Private Member Functions
void *	DoAllocate (Layout layout) override
void	DoDeallocate (void *ptr) override
Result< Layout >	DoGetInfo (InfoType info_type, const void *ptr) const override

Additional Inherited Members
Protected Member Functions inherited from pw::Allocator
constexpr	Allocator ()=default
	TODO(b/326509341): Remove when downstream consumers migrate.
constexpr	Allocator (const Capabilities &capabilities)
Protected Member Functions inherited from pw::Deallocator
constexpr	Deallocator ()=default
	TODO(b/326509341): Remove when downstream consumers migrate.
constexpr	Deallocator (const Capabilities &capabilities)
template<typename T , std::enable_if_t<!std::is_array_v< T >, int > = 0>
UniquePtr< T >	WrapUnique (T *ptr)
template<typename T , int &... kExplicitGuard, typename ElementType = std::remove_extent_t<T>, std::enable_if_t< is_unbounded_array_v< T >, int > = 0>
UniquePtr< T >	WrapUnique (ElementType *ptr, size_t size)
template<typename T >
UniquePtr< T[]>	WrapUniqueArray (T *ptr, size_t size)
Static Protected Attributes inherited from pw::Deallocator
template<typename T >
static constexpr bool	is_bounded_array_v
template<typename T >
static constexpr bool	is_unbounded_array_v

Detailed Description

template<size_t kMinOuterSize_ = internal::GenericBuddyAllocator::kDefaultMinOuterSize, size_t kNumBuckets = internal::GenericBuddyAllocator::kDefaultNumBuckets>
class pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets >

Allocator that uses the buddy memory allocation algorithm.

This allocator allocates blocks of memory whose sizes are powers of two. This allows the allocator to satisfy requests to acquire and release memory very quickly, at the possible cost of higher internal fragmentation. In particular:

• The maximum alignment for this allocator is kMinInnerSize.
• The minimum size of an allocation is kMinInnerSize. Less may be requested, but it will be satisfied by a block of that inner size.
• The maximum size of an allocation is kMinInnerSize << (kNumBuckets - 1).

Use this allocator if you know the needed sizes are close to but less than the block inner sizes and you need high allocator performance.

Template Parameters

kMinOuterSize	Outer size of the smallest allocatable block. Must be a power of two. All allocations will use at least this much memory.
kNumBuckets	Number of buckets. Must be at least 1. Each additional bucket allows combining blocks into larger blocks.

Constructor & Destructor Documentation

BuddyAllocator()

template<size_t kMinOuterSize_ = internal::GenericBuddyAllocator::kDefaultMinOuterSize, size_t kNumBuckets = internal::GenericBuddyAllocator::kDefaultNumBuckets>

pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets >::BuddyAllocator ( ByteSpan  region )

inline

Constructs an allocator, and initializes it with the given memory region.

Parameters

[in]

region

Region of memory to use when satisfying allocation requests. The region MUST be large enough to fit a least one minimally-size BuddyBlock.

Member Function Documentation

DoAllocate()

template<size_t kMinOuterSize_ = internal::GenericBuddyAllocator::kDefaultMinOuterSize, size_t kNumBuckets = internal::GenericBuddyAllocator::kDefaultNumBuckets>

void * pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets >::DoAllocate ( Layout  layout )

inlineoverrideprivatevirtual

Allocates a block of memory with the specified size and alignment.

Returns nullptr if the allocation cannot be made, or the layout has a size of 0.

Parameters

[in]

layout

Describes the memory to be allocated.

Implements pw::Allocator.

DoDeallocate()

template<size_t kMinOuterSize_ = internal::GenericBuddyAllocator::kDefaultMinOuterSize, size_t kNumBuckets = internal::GenericBuddyAllocator::kDefaultNumBuckets>

void pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets >::DoDeallocate ( void *  ptr )

inlineoverrideprivate

DoGetInfo()

template<size_t kMinOuterSize_ = internal::GenericBuddyAllocator::kDefaultMinOuterSize, size_t kNumBuckets = internal::GenericBuddyAllocator::kDefaultNumBuckets>

Result< Layout > pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets >::DoGetInfo ( InfoType  info_type, const void *  ptr  ) const

inlineoverrideprivate

Init()

template<size_t kMinOuterSize_ = internal::GenericBuddyAllocator::kDefaultMinOuterSize, size_t kNumBuckets = internal::GenericBuddyAllocator::kDefaultNumBuckets>

void pw::allocator::BuddyAllocator< kMinOuterSize_, kNumBuckets >::Init ( ByteSpan  region )

inline

Sets the memory region used by the allocator.

Parameters

[in]

region

Region of memory to use when satisfying allocation requests. The region MUST be large enough to fit a least one minimally-size BuddyBlock.

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The documentation for this class was generated from the following file:

• pw_allocator/public/pw_allocator/buddy_allocator.h