src/share/vm/runtime/sweeper.cpp

rev 13233 : 8180932: Parallelize safepoint cleanup
Summary: Provide infrastructure to do safepoint cleanup tasks using parallel worker threads
Reviewed-by: dholmes, rehn, dcubed, thartmann

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -110,11 +110,11 @@
 }
 
 void NMethodSweeper::record_sweep(CompiledMethod* nm, int line) {
   if (_records != NULL) {
     _records[_sweep_index].traversal = _traversals;
-    _records[_sweep_index].traversal_mark = nm->is_nmethod() ? ((nmethod*)nm)->_stack_traversal_mark : 0;
+    _records[_sweep_index].traversal_mark = nm->is_nmethod() ? ((nmethod*)nm)->stack_traversal_mark() : 0;
     _records[_sweep_index].compile_id = nm->compile_id();
     _records[_sweep_index].kind = nm->compile_kind();
     _records[_sweep_index].state = nm->get_state();
     _records[_sweep_index].vep = nm->verified_entry_point();
     _records[_sweep_index].uep = nm->entry_point();

@@ -197,15 +197,22 @@
   * Scans the stacks of all Java threads and marks activations of not-entrant methods.
   * No need to synchronize access, since 'mark_active_nmethods' is always executed at a
   * safepoint.
   */
 void NMethodSweeper::mark_active_nmethods() {
+  CodeBlobClosure* cl = prepare_mark_active_nmethods();
+  if (cl != NULL) {
+    Threads::nmethods_do(cl);
+  }
+}
+
+CodeBlobClosure* NMethodSweeper::prepare_mark_active_nmethods() {
   assert(SafepointSynchronize::is_at_safepoint(), "must be executed at a safepoint");
   // If we do not want to reclaim not-entrant or zombie methods there is no need
   // to scan stacks
   if (!MethodFlushing) {
-    return;
+    return NULL;
   }
 
   // Increase time so that we can estimate when to invoke the sweeper again.
   _time_counter++;
 

@@ -229,18 +236,17 @@
     _total_time_this_sweep = Tickspan();
 
     if (PrintMethodFlushing) {
       tty->print_cr("### Sweep: stack traversal %ld", _traversals);
     }
-    Threads::nmethods_do(&mark_activation_closure);
+    return &mark_activation_closure;
 
   } else {
     // Only set hotness counter
-    Threads::nmethods_do(&set_hotness_closure);
+    return &set_hotness_closure;
   }
 
-  OrderAccess::storestore();
 }
 
 /**
   * This function triggers a VM operation that does stack scanning of active
   * methods. Stack scanning is mandatory for the sweeper to make progress.