This is a mmap based memory allocator, allow users to allocate dynamic memory in mmap region 
instead of heap, initially inspired by BigMaac allocator.
Processes which do not have enough swap space (such as processes running in an access-limited 
container) will benefit from swapping through kernel managed file cache.

The allocator is compiled as a linux dynamic library. You can use:
% LD_PRELOAD=$PATH_TO_LIB executable arguments
to execute whatever you want and replace the std allocator by the mmap allocator.

To build the library:
% make all

The path to the compiled library:
$PROJECT_PATH/build/lib/libmmap_allocator.so

Configurable environment variables:
ENV_MMAP_HEAP_SIZE: max mmap heap size, must be page aligned.
ENV_MMAP_ALLOCATOR_MIN_BSIZE: min block size which will be allocated in mmap region.
ENV_NAMING_TEMPLATE: path to the temp mmap files (invisible from fs during the runtime).
ENV_PROFILE_FILE_PATH: path to the profile file. Given this parameter to turn on the profiling.
ENV_PROFILE_FREQUENCY: profiling frequency in seconds.