PooledVirtualMemoryAllocator.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "HAL/Allocators/CachedOSPageAllocator.h"
#include "HAL/PlatformMutex.h"
 
struct FPooledVirtualMemoryAllocator
{
    FPooledVirtualMemoryAllocator();
 
    void* Allocate(SIZE_T Size, uint32 AllocationHint = 0, UE::FPlatformRecursiveMutex* Mutex = nullptr);
    void Free(void* Ptr, SIZE_T Size, UE::FPlatformRecursiveMutex* Mutex = nullptr, bool ThreadIsTimeCritical = false);
    void FreeAll(UE::FPlatformRecursiveMutex* Mutex = nullptr);
 
    struct FPoolDescriptorBase
    {
        FPoolDescriptorBase* Next;
 
        SIZE_T VMSizeDivVirtualSizeAlignment;
    };
 
    uint64 GetCachedFreeTotal() const;
    uint64 GetCachedImmediatelyFreeable() const
    {
        return GetCachedFreeTotal();
    }
 
    void Refresh() {}
 
    void UpdateStats() {}
 
    void DumpAllocatorStats(class FOutputDevice& Ar);
 
private:
 
    enum Limits
    {
        NumAllocationSizeClasses    = 64,
        MaxAllocationSizeToPool     = NumAllocationSizeClasses * 65536,
 
        MaxOSAllocCacheSize         = 64 * 1024 * 1024,
        MaxOSAllocsCached           = 64
    };
 
    UE_FORCEINLINE_HINT int32 GetAllocationSizeClass(SIZE_T Size)
    {
        return static_cast<int32>(Size >> 16) + ((Size & 0xFFFF) ? 1 : 0) - 1;
    }
 
    UE_FORCEINLINE_HINT SIZE_T CalculateAllocationSizeFromClass(int32 Class)
    {
        return (static_cast<SIZE_T>(Class) + 1) * 65536;
    }
 
    int32 NextPoolSize[Limits::NumAllocationSizeClasses];
 
    FPoolDescriptorBase* ClassesListHeads[Limits::NumAllocationSizeClasses];
 
    mutable UE::FPlatformRecursiveMutex ClassesLocks[Limits::NumAllocationSizeClasses];
 
    void DecideOnTheNextPoolSize(int32 SizeClass, bool bGrowing);
 
    FPoolDescriptorBase* CreatePool(SIZE_T AllocationSize, int32 NumPooledAllocations);
 
    void DestroyPool(FPoolDescriptorBase* Pool);
 
    UE::FPlatformRecursiveMutex OsAllocatorCacheLock;
 
    TCachedOSPageAllocator<MaxOSAllocsCached, MaxOSAllocCacheSize> OsAllocatorCache;
};
 
#if UE_ENABLE_INCLUDE_ORDER_DEPRECATED_IN_5_7
#   include "HAL/CriticalSection.h"
#endif