Static GC_full_freq 

pub unsafe static mut GC_full_freq: c_int

Number of partial collections between full collections. Matters only if GC_is_incremental_mode(). Full collections are also triggered if the collector detects a substantial increase in the number of the in-use heap blocks. Values in the tens are now perfectly reasonable. The setter and the getter are unsynchronized, so GC_call_with_alloc_lock() (GC_call_with_reader_lock() in case of the getter) is required to avoid data race (if the value is modified after the collector is put into the multi-threaded mode).