413   // Keeps track of how many "old marking cycles" (i.e., Full GCs or

   413   // Keeps track of how many "old marking cycles" (i.e., Full GCs or

   414   // concurrent cycles) we have completed.

   414   // concurrent cycles) we have completed.

   415   volatile unsigned int _old_marking_cycles_completed;

   415   volatile unsigned int _old_marking_cycles_completed;

   416 

   416 

   417   bool _concurrent_cycle_started;

   417   bool _concurrent_cycle_started;

   418 

   419 

   419   // This is a non-product method that is helpful for testing. It is

   420   // This is a non-product method that is helpful for testing. It is

   420   // called at the end of a GC and artificially expands the heap by

   421   // called at the end of a GC and artificially expands the heap by

   421   // allocating a number of dead regions. This way we can induce very

   422   // allocating a number of dead regions. This way we can induce very

   422   // frequent marking cycles and stress the cleanup / concurrent

   423   // frequent marking cycles and stress the cleanup / concurrent