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version 2.101.0

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Struct std.experimental.allocator.building_blocks.ascending_page_allocator.SharedAscendingPageAllocator

SharedAscendingPageAllocator is the threadsafe version of AscendingPageAllocator.

struct SharedAscendingPageAllocator ;

Constructors

NameDescription
this (n) Rounds the mapping size to the next multiple of the page size and calls the OS primitive responsible for creating memory mappings: mmap on POSIX and VirtualAlloc on Windows.

Methods

NameDescription
alignedAllocate (n, a) Rounds the allocation size to the next multiple of the page size. The allocation only reserves a range of virtual pages but the actual physical memory is allocated on demand, when accessing the memory.
allocate (n) Rounds the allocation size to the next multiple of the page size. The allocation only reserves a range of virtual pages but the actual physical memory is allocated on demand, when accessing the memory.
deallocate (b) Decommit all physical memory associated with the buffer given as parameter, but keep the range of virtual addresses.
deallocateAll () Removes the memory mapping causing all physical memory to be decommited and the virtual address space to be reclaimed.
expand (b, delta) If the passed buffer is not the last allocation, then delta can be at most the number of bytes left on the last page. Otherwise, we can expand the last allocation until the end of the virtual address range.
getAvailableSize () Returns the available size for further allocations in bytes.
goodAllocSize (n) Rounds the requested size to the next multiple of the page size.
owns (buf) Returns Ternary.yes if the passed buffer is inside the range of virtual adresses. Does not guarantee that the passed buffer is still valid.

Example

import core.memory : pageSize;
import core.thread : ThreadGroup;

enum numThreads = 100;
shared SharedAscendingPageAllocator a = SharedAscendingPageAllocator(pageSize * numThreads);

void fun()
{
    void[] b = a.allocate(pageSize);
    writeln(b.length); // pageSize

    assert(a.deallocate(b));
}

auto tg = new ThreadGroup;
foreach (i; 0 .. numThreads)
{
    tg.create(&fun);
}
tg.joinAll();

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