std::experimental::pmr::monotonic_buffer_resource::do_allocate (3) - Linux Man Pages
virtual void* do_allocate(std::size_t bytes, std::size_t alignment); (library fundamentals TS)
If the current buffer has sufficient unused space to fit a block with the specified size and alignment, allocates the return block from the current buffer.
Otherwise, this function allocates a new buffer by calling upstream_resource()->allocate(n, m), where n is not less than the greater of bytes and the next buffer size and m is not less than alignment. It sets the new buffer as the current buffer, increases the next buffer size by an implementation-defined growth factor (which is not necessarily integral), and then allocates the return block from the newly allocated buffer.
A pointer to allocated storage of at least bytes bytes in size, aligned to the specified alignment if such alignment is supported, and to alignof(std::max_align_t) otherwise.
Throws nothing unless calling allocate() on the upstream memory resource throws.
allocate (public member function of std::experimental::pmr::memory_resource)
do_allocate allocates memory