src/hotspot/share/gc/g1/g1FullCollector.cpp

@@ -40,10 +40,11 @@
  #include "gc/g1/g1Policy.hpp"
  #include "gc/g1/g1RegionMarkStatsCache.inline.hpp"
  #include "gc/shared/gcTraceTime.inline.hpp"
  #include "gc/shared/preservedMarks.hpp"
  #include "gc/shared/referenceProcessor.hpp"
+ #include "gc/shared/slidingForwarding.hpp"
  #include "gc/shared/verifyOption.hpp"
  #include "gc/shared/weakProcessor.inline.hpp"
  #include "gc/shared/workerPolicy.hpp"
  #include "logging/log.hpp"
  #include "runtime/handles.inline.hpp"

@@ -328,10 +329,12 @@
  }
  
  void G1FullCollector::phase2_prepare_compaction() {
    GCTraceTime(Info, gc, phases) info("Phase 2: Prepare compaction", scope()->timer());
  
+   _heap->forwarding()->clear();
+ 
    phase2a_determine_worklists();
  
    if (!has_compaction_targets()) {
      return;
    }

@@ -339,13 +342,14 @@
    bool has_free_compaction_targets = phase2b_forward_oops();
  
    // Try to avoid OOM immediately after Full GC in case there are no free regions
    // left after determining the result locations (i.e. this phase). Prepare to
    // maximally compact the tail regions of the compaction queues serially.
-   if (scope()->do_maximal_compaction() || !has_free_compaction_targets) {
-     phase2c_prepare_serial_compaction();
-   }
+   // TODO: Disabled for now because it violates sliding-forwarding assumption.
+ //  if (scope()->do_maximal_compaction() || !has_free_compaction_targets) {
+ //    phase2c_prepare_serial_compaction();
+ //  }
  }
  
  void G1FullCollector::phase2a_determine_worklists() {
    GCTraceTime(Debug, gc, phases) debug("Phase 2: Determine work lists", scope()->timer());
  

@@ -360,65 +364,65 @@
    run_task(&task);
  
    return task.has_free_compaction_targets();
  }
  
- uint G1FullCollector::truncate_parallel_cps() {
-   uint lowest_current = (uint)-1;
-   for (uint i = 0; i < workers(); i++) {
-     G1FullGCCompactionPoint* cp = compaction_point(i);
-     if (cp->has_regions()) {
-       lowest_current = MIN2(lowest_current, cp->current_region()->hrm_index());
-     }
-   }
- 
-   for (uint i = 0; i < workers(); i++) {
-     G1FullGCCompactionPoint* cp = compaction_point(i);
-     if (cp->has_regions()) {
-       cp->remove_at_or_above(lowest_current);
-     }
-   }
-   return lowest_current;
- }
- 
- void G1FullCollector::phase2c_prepare_serial_compaction() {
-   GCTraceTime(Debug, gc, phases) debug("Phase 2: Prepare serial compaction", scope()->timer());
-   // At this point, we know that after parallel compaction there will be regions that
-   // are partially compacted into. Thus, the last compaction region of all
-   // compaction queues still have space in them. We try to re-compact these regions
-   // in serial to avoid a premature OOM when the mutator wants to allocate the first
-   // eden region after gc.
- 
-   // For maximum compaction, we need to re-prepare all objects above the lowest
-   // region among the current regions for all thread compaction points. It may
-   // happen that due to the uneven distribution of objects to parallel threads, holes
-   // have been created as threads compact to different target regions between the
-   // lowest and the highest region in the tails of the compaction points.
- 
-   uint start_serial = truncate_parallel_cps();
-   assert(start_serial < _heap->max_reserved_regions(), "Called on empty parallel compaction queues");
- 
-   G1FullGCCompactionPoint* serial_cp = serial_compaction_point();
-   assert(!serial_cp->is_initialized(), "sanity!");
- 
-   HeapRegion* start_hr = _heap->region_at(start_serial);
-   serial_cp->add(start_hr);
-   serial_cp->initialize(start_hr);
- 
-   HeapWord* dense_prefix_top = compaction_top(start_hr);
-   G1SerialRePrepareClosure re_prepare(serial_cp, dense_prefix_top);
- 
-   for (uint i = start_serial + 1; i < _heap->max_reserved_regions(); i++) {
-     if (is_compaction_target(i)) {
-       HeapRegion* current = _heap->region_at(i);
-       set_compaction_top(current, current->bottom());
-       serial_cp->add(current);
-       current->apply_to_marked_objects(mark_bitmap(), &re_prepare);
-     }
-   }
-   serial_cp->update();
- }
+ //uint G1FullCollector::truncate_parallel_cps() {
+ //  uint lowest_current = (uint)-1;
+ //  for (uint i = 0; i < workers(); i++) {
+ //    G1FullGCCompactionPoint* cp = compaction_point(i);
+ //    if (cp->has_regions()) {
+ //      lowest_current = MIN2(lowest_current, cp->current_region()->hrm_index());
+ //    }
+ //  }
+ 
+ //  for (uint i = 0; i < workers(); i++) {
+ //    G1FullGCCompactionPoint* cp = compaction_point(i);
+ //    if (cp->has_regions()) {
+ //      cp->remove_at_or_above(lowest_current);
+ //    }
+ //  }
+ //  return lowest_current;
+ //}
+ 
+ //void G1FullCollector::phase2c_prepare_serial_compaction() {
+ //  GCTraceTime(Debug, gc, phases) debug("Phase 2: Prepare serial compaction", scope()->timer());
+ //  // At this point, we know that after parallel compaction there will be regions that
+ //  // are partially compacted into. Thus, the last compaction region of all
+ //  // compaction queues still have space in them. We try to re-compact these regions
+ //  // in serial to avoid a premature OOM when the mutator wants to allocate the first
+ //  // eden region after gc.
+ //
+ //  // For maximum compaction, we need to re-prepare all objects above the lowest
+ //  // region among the current regions for all thread compaction points. It may
+ //  // happen that due to the uneven distribution of objects to parallel threads, holes
+ //  // have been created as threads compact to different target regions between the
+ //  // lowest and the highest region in the tails of the compaction points.
+ //
+ //  uint start_serial = truncate_parallel_cps();
+ //  assert(start_serial < _heap->max_reserved_regions(), "Called on empty parallel compaction queues");
+ //
+ //  G1FullGCCompactionPoint* serial_cp = serial_compaction_point();
+ //  assert(!serial_cp->is_initialized(), "sanity!");
+ //
+ //  HeapRegion* start_hr = _heap->region_at(start_serial);
+ //  serial_cp->add(start_hr);
+ //  serial_cp->initialize(start_hr);
+ //
+ //  HeapWord* dense_prefix_top = compaction_top(start_hr);
+ //  G1SerialRePrepareClosure re_prepare(serial_cp, dense_prefix_top);
+ //
+ //  for (uint i = start_serial + 1; i < _heap->max_reserved_regions(); i++) {
+ //    if (is_compaction_target(i)) {
+ //      HeapRegion* current = _heap->region_at(i);
+ //      set_compaction_top(current, current->bottom());
+ //      serial_cp->add(current);
+ //      current->apply_to_marked_objects(mark_bitmap(), &re_prepare);
+ //    }
+ //  }
+ //  serial_cp->update();
+ //}
  
  void G1FullCollector::phase3_adjust_pointers() {
    // Adjust the pointers to reflect the new locations
    GCTraceTime(Info, gc, phases) info("Phase 3: Adjust pointers", scope()->timer());