Function mspace_track_large_chunks 

pub unsafe extern "C" fn mspace_track_large_chunks(
    msp: *mut c_void,
    enable: i32,
) -> i32

mspace_track_large_chunks controls whether requests for large chunks are allocated in their own untracked mmapped regions, separate from others in this mspace. By default large chunks are not tracked, which reduces fragmentation. However, such chunks are not necessarily released to the system upon destroy_mspace. Enabling tracking by setting to true may increase fragmentation, but avoids leakage when relying on destroy_mspace to release all memory allocated using this space. The function returns the previous setting.