368   assert(max_level < n_gens(), "sanity check");
 369 
 370   if (GC_locker::check_active_before_gc()) {
 371     return; // GC is disabled (e.g. JNI GetXXXCritical operation)
 372   }
 373 
 374   const bool do_clear_all_soft_refs = clear_all_soft_refs ||
 375                           collector_policy()->should_clear_all_soft_refs();
 376 
 377   ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
 378 
 379   const size_t metadata_prev_used = MetaspaceAux::used_in_bytes();
 380 
 381   print_heap_before_gc();
 382 
 383   {
 384     FlagSetting fl(_is_gc_active, true);
 385 
 386     bool complete = full && (max_level == (n_gens()-1));
 387     const char* gc_cause_prefix = complete ? "Full GC" : "GC";
 388     gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
 389     TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
 390     TraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, gclog_or_tty);
 391 
 392     gc_prologue(complete);
 393     increment_total_collections(complete);
 394 
 395     size_t gch_prev_used = used();
 396 
 397     int starting_level = 0;
 398     if (full) {
 399       // Search for the oldest generation which will collect all younger
 400       // generations, and start collection loop there.
 401       for (int i = max_level; i >= 0; i--) {
 402         if (_gens[i]->full_collects_younger_generations()) {
 403           starting_level = i;
 404           break;
 405         }
 406       }
 407     }
 408 

 368   assert(max_level < n_gens(), "sanity check");
 369 
 370   if (GC_locker::check_active_before_gc()) {
 371     return; // GC is disabled (e.g. JNI GetXXXCritical operation)
 372   }
 373 
 374   const bool do_clear_all_soft_refs = clear_all_soft_refs ||
 375                           collector_policy()->should_clear_all_soft_refs();
 376 
 377   ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
 378 
 379   const size_t metadata_prev_used = MetaspaceAux::used_in_bytes();
 380 
 381   print_heap_before_gc();
 382 
 383   {
 384     FlagSetting fl(_is_gc_active, true);
 385 
 386     bool complete = full && (max_level == (n_gens()-1));
 387     const char* gc_cause_prefix = complete ? "Full GC" : "GC";

 388     TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
 389     TraceTime t(GCCauseString(gc_cause_prefix, gc_cause()), PrintGCDetails, false, gclog_or_tty);
 390 
 391     gc_prologue(complete);
 392     increment_total_collections(complete);
 393 
 394     size_t gch_prev_used = used();
 395 
 396     int starting_level = 0;
 397     if (full) {
 398       // Search for the oldest generation which will collect all younger
 399       // generations, and start collection loop there.
 400       for (int i = max_level; i >= 0; i--) {
 401         if (_gens[i]->full_collects_younger_generations()) {
 402           starting_level = i;
 403           break;
 404         }
 405       }
 406     }
 407