INITIAL_MARK_STACK_SIZE   60 gc/include/private/gc_pmark.h #define GC_MARK_STACK_DISCARDS (INITIAL_MARK_STACK_SIZE/8)
INITIAL_MARK_STACK_SIZE   86 gc/mark.c      # ifndef INITIAL_MARK_STACK_SIZE
INITIAL_MARK_STACK_SIZE  288 gc/mark.c          	        >= GC_mark_stack_limit - INITIAL_MARK_STACK_SIZE/2) {
INITIAL_MARK_STACK_SIZE 1184 gc/mark.c          alloc_mark_stack(INITIAL_MARK_STACK_SIZE);