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src/hotspot/share/gc/shenandoah/shenandoahMark.cpp

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@@ -1,7 +1,8 @@
  /*
   * Copyright (c) 2021, 2022, Red Hat, Inc. All rights reserved.
+  * Copyright Amazon.com Inc. 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.

@@ -25,80 +26,95 @@
  
  #include "precompiled.hpp"
  
  #include "gc/shenandoah/shenandoahBarrierSet.hpp"
  #include "gc/shenandoah/shenandoahClosures.inline.hpp"
+ #include "gc/shenandoah/shenandoahGeneration.hpp"
  #include "gc/shenandoah/shenandoahMark.inline.hpp"
  #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
  #include "gc/shenandoah/shenandoahReferenceProcessor.hpp"
  #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
  #include "gc/shenandoah/shenandoahUtils.hpp"
  #include "gc/shenandoah/shenandoahVerifier.hpp"
  
- ShenandoahMarkRefsSuperClosure::ShenandoahMarkRefsSuperClosure(ShenandoahObjToScanQueue* q,  ShenandoahReferenceProcessor* rp) :
-   MetadataVisitingOopIterateClosure(rp),
-   _queue(q),
-   _mark_context(ShenandoahHeap::heap()->marking_context()),
-   _weak(false)
- { }
- 
- ShenandoahMark::ShenandoahMark() :
-   _task_queues(ShenandoahHeap::heap()->marking_context()->task_queues()) {
- }
- 
  void ShenandoahMark::start_mark() {
    if (!CodeCache::is_gc_marking_cycle_active()) {
      CodeCache::on_gc_marking_cycle_start();
    }
  }
  
  void ShenandoahMark::end_mark() {
    // Unlike other GCs, we do not arm the nmethods
    // when marking terminates.
-   CodeCache::on_gc_marking_cycle_finish();
+   if (!ShenandoahHeap::heap()->is_concurrent_old_mark_in_progress()) {
+     CodeCache::on_gc_marking_cycle_finish();
+   }
  }
  
- void ShenandoahMark::clear() {
-   // Clean up marking stacks.
-   ShenandoahObjToScanQueueSet* queues = ShenandoahHeap::heap()->marking_context()->task_queues();
-   queues->clear();
+ ShenandoahMarkRefsSuperClosure::ShenandoahMarkRefsSuperClosure(ShenandoahObjToScanQueue* q,  ShenandoahReferenceProcessor* rp, ShenandoahObjToScanQueue* old_q) :
+   MetadataVisitingOopIterateClosure(rp),
+   _queue(q),
+   _old_queue(old_q),
+   _mark_context(ShenandoahHeap::heap()->marking_context()),
+   _weak(false)
+ { }
  
-   // Cancel SATB buffers.
-   ShenandoahBarrierSet::satb_mark_queue_set().abandon_partial_marking();
+ ShenandoahMark::ShenandoahMark(ShenandoahGeneration* generation) :
+   _generation(generation),
+   _task_queues(generation->task_queues()),
+   _old_gen_task_queues(generation->old_gen_task_queues()) {
  }
  
  template <ShenandoahGenerationType GENERATION, bool CANCELLABLE, StringDedupMode STRING_DEDUP>
- void ShenandoahMark::mark_loop_prework(uint w, TaskTerminator *t, ShenandoahReferenceProcessor *rp, StringDedup::Requests* const req) {
+ void ShenandoahMark::mark_loop_prework(uint w, TaskTerminator *t, ShenandoahReferenceProcessor *rp, StringDedup::Requests* const req, bool update_refs) {
    ShenandoahObjToScanQueue* q = get_queue(w);
+   ShenandoahObjToScanQueue* old_q = get_old_queue(w);
  
    ShenandoahHeap* const heap = ShenandoahHeap::heap();
    ShenandoahLiveData* ld = heap->get_liveness_cache(w);
  
    // TODO: We can clean up this if we figure out how to do templated oop closures that
    // play nice with specialized_oop_iterators.
-   if (heap->has_forwarded_objects()) {
+   if (update_refs) {
      using Closure = ShenandoahMarkUpdateRefsClosure<GENERATION>;
-     Closure cl(q, rp);
+     Closure cl(q, rp, old_q);
      mark_loop_work<Closure, GENERATION, CANCELLABLE, STRING_DEDUP>(&cl, ld, w, t, req);
    } else {
      using Closure = ShenandoahMarkRefsClosure<GENERATION>;
-     Closure cl(q, rp);
+     Closure cl(q, rp, old_q);
      mark_loop_work<Closure, GENERATION, CANCELLABLE, STRING_DEDUP>(&cl, ld, w, t, req);
    }
  
    heap->flush_liveness_cache(w);
  }
  
  template<bool CANCELLABLE, StringDedupMode STRING_DEDUP>
  void ShenandoahMark::mark_loop(uint worker_id, TaskTerminator* terminator, ShenandoahReferenceProcessor *rp,
                                 ShenandoahGenerationType generation, StringDedup::Requests* const req) {
-   mark_loop_prework<NON_GEN, CANCELLABLE, STRING_DEDUP>(worker_id, terminator, rp, req);
+   bool update_refs = ShenandoahHeap::heap()->has_forwarded_objects();
+   switch (generation) {
+     case YOUNG:
+       mark_loop_prework<YOUNG, CANCELLABLE, STRING_DEDUP>(worker_id, terminator, rp, req, update_refs);
+       break;
+     case OLD:
+       // Old generation collection only performs marking, it should not update references.
+       mark_loop_prework<OLD, CANCELLABLE, STRING_DEDUP>(worker_id, terminator, rp, req, false);
+       break;
+     case GLOBAL:
+       mark_loop_prework<GLOBAL, CANCELLABLE, STRING_DEDUP>(worker_id, terminator, rp, req, update_refs);
+       break;
+     case NON_GEN:
+       mark_loop_prework<NON_GEN, CANCELLABLE, STRING_DEDUP>(worker_id, terminator, rp, req, update_refs);
+       break;
+     default:
+       ShouldNotReachHere();
+       break;
+   }
  }
  
  void ShenandoahMark::mark_loop(uint worker_id, TaskTerminator* terminator, ShenandoahReferenceProcessor *rp,
-                                ShenandoahGenerationType generation, bool cancellable,  StringDedupMode dedup_mode,
-                                StringDedup::Requests* const req) {
+                                ShenandoahGenerationType generation, bool cancellable, StringDedupMode dedup_mode, StringDedup::Requests* const req) {
    if (cancellable) {
      switch(dedup_mode) {
        case NO_DEDUP:
          mark_loop<true, NO_DEDUP>(worker_id, terminator, rp, generation, req);
          break;

@@ -131,11 +147,16 @@
    ShenandoahHeap* heap = ShenandoahHeap::heap();
    ShenandoahObjToScanQueueSet* queues = task_queues();
    ShenandoahObjToScanQueue* q;
    ShenandoahMarkTask t;
  
-   heap->ref_processor()->set_mark_closure(worker_id, cl);
+   // Do not use active_generation() : we must use the gc_generation() set by
+   // ShenandoahGCScope on the ControllerThread's stack; no safepoint may
+   // intervene to update active_generation, so we can't
+   // shenandoah_assert_generations_reconciled() here.
+   assert(heap->gc_generation()->type() == GENERATION, "Sanity: %d != %d", heap->gc_generation()->type(), GENERATION);
+   heap->gc_generation()->ref_processor()->set_mark_closure(worker_id, cl);
  
    /*
     * Process outstanding queues, if any.
     *
     * There can be more queues than workers. To deal with the imbalance, we claim

@@ -151,40 +172,40 @@
        return;
      }
  
      for (uint i = 0; i < stride; i++) {
        if (q->pop(t)) {
-         do_task<T, GENERATION, STRING_DEDUP>(q, cl, live_data, req, &t);
+         do_task<T, GENERATION, STRING_DEDUP>(q, cl, live_data, req, &t, worker_id);
        } else {
          assert(q->is_empty(), "Must be empty");
          q = queues->claim_next();
          break;
        }
      }
    }
    q = get_queue(worker_id);
+   ShenandoahObjToScanQueue* old_q = get_old_queue(worker_id);
  
-   ShenandoahSATBBufferClosure<GENERATION> drain_satb(q);
+   ShenandoahSATBBufferClosure<GENERATION> drain_satb(q, old_q);
    SATBMarkQueueSet& satb_mq_set = ShenandoahBarrierSet::satb_mark_queue_set();
  
    /*
     * Normal marking loop:
     */
    while (true) {
      if (CANCELLABLE && heap->check_cancelled_gc_and_yield()) {
        return;
      }
- 
      while (satb_mq_set.completed_buffers_num() > 0) {
        satb_mq_set.apply_closure_to_completed_buffer(&drain_satb);
      }
  
      uint work = 0;
      for (uint i = 0; i < stride; i++) {
        if (q->pop(t) ||
            queues->steal(worker_id, t)) {
-         do_task<T, GENERATION, STRING_DEDUP>(q, cl, live_data, req, &t);
+         do_task<T, GENERATION, STRING_DEDUP>(q, cl, live_data, req, &t, worker_id);
          work++;
        } else {
          break;
        }
      }
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