func sysUnusedOS(v unsafe.Pointer, n uintptr) {
	// MADV_FREE_REUSABLE is like MADV_FREE except it also propagates
	// accounting information about the process to task_info.
	madvise(v, n, _MADV_FREE_REUSABLE)
}

func sysUsedOS(v unsafe.Pointer, n uintptr) {
	// MADV_FREE_REUSE is necessary to keep the kernel's accounting
	// accurate. If called on any memory region that hasn't been
	// MADV_FREE_REUSABLE'd, it's a no-op.

			exit(2)
		}
		return nil
	}
	return p
}

func sysUnusedOS(v unsafe.Pointer, n uintptr) {
	madvise(v, n, _MADV_DONTNEED)
}

func sysUsedOS(v unsafe.Pointer, n uintptr) {
}

func sysHugePageOS(v unsafe.Pointer, n uintptr) {
}

func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
}

func sysHugePageCollapseOS(v unsafe.Pointer, n uintptr) {
}

		return nil
	}
	return v
}

func sysUnusedOS(v unsafe.Pointer, n uintptr) {
	if debug.madvdontneed != 0 {
		madvise(v, n, _MADV_DONTNEED)
	} else {
		madvise(v, n, _MADV_FREE)
	}
}

func sysUsedOS(v unsafe.Pointer, n uintptr) {
}

func sysHugePageOS(v unsafe.Pointer, n uintptr) {
}

func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
}

func sysHugePageCollapseOS(v unsafe.Pointer, n uintptr) {
}

		memclrNoHeapPointers(v, n)
		bloc -= n
	} else {
		memFree(v, n)
		memCheck()
	}
	unlock(&memlock)
}

func sysUnusedOS(v unsafe.Pointer, n uintptr) {
}

func sysUsedOS(v unsafe.Pointer, n uintptr) {
}

func sysHugePageOS(v unsafe.Pointer, n uintptr) {
}

func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
}

func sysHugePageCollapseOS(v unsafe.Pointer, n uintptr) {

		if small < 4096 {
			print("runtime: VirtualFree of ", small, " bytes failed with errno=", getlasterror(), "\n")
			throw("runtime: failed to decommit pages")
		}
		v = add(v, small)
		n -= small
	}
}

func sysUsedOS(v unsafe.Pointer, n uintptr) {
	p := stdcall4(_VirtualAlloc, uintptr(v), n, _MEM_COMMIT, _PAGE_READWRITE)
	if p == uintptr(v) {
		return
	}

	// Commit failed. See SysUnused.

	if debug.harddecommit > 0 {
		p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
		if p != v || err != 0 {
			throw("runtime: cannot disable permissions in address space")
		}
	}
}

func sysUsedOS(v unsafe.Pointer, n uintptr) {
	if debug.harddecommit > 0 {
		p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
		if err == _ENOMEM {
			throw("runtime: out of memory")
		}

// Prepared and Ready memory. However, the caller must provide the exact amount
// of Prepared memory for accounting purposes.
func sysUsed(v unsafe.Pointer, n, prepared uintptr) {
	gcController.mappedReady.Add(int64(prepared))
	sysUsedOS(v, n)
}

// sysHugePage does not transition memory regions, but instead provides a
// hint to the OS that it would be more efficient to back this memory region
// with pages of a larger size transparently.