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changeset 9623:261ef52a9f2f

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Several smaller fixes to mark-compact: Fix derived pointers, more efficient next-compaction-region, initialize freed humongous regions correctly.
author rkennke
date Fri, 18 Sep 2015 15:44:29 +0200
parents 263be3296c38
children 790069ea3727
files src/share/vm/gc/shenandoah/shenandoahHeap.cpp src/share/vm/gc/shenandoah/shenandoahHeap.hpp src/share/vm/gc/shenandoah/shenandoahHeapRegion.cpp src/share/vm/gc/shenandoah/shenandoahHeapRegion.hpp src/share/vm/gc/shenandoah/shenandoahMarkCompact.cpp
diffstat 5 files changed, 27 insertions(+), 12 deletions(-) [+]
line wrap: on
line diff
--- a/src/share/vm/gc/shenandoah/shenandoahHeap.cpp	Wed Sep 16 17:22:25 2015 +0200
+++ b/src/share/vm/gc/shenandoah/shenandoahHeap.cpp	Fri Sep 18 15:44:29 2015 +0200
@@ -2849,11 +2849,13 @@
 }
 
 ShenandoahHeapRegion* ShenandoahHeap::next_compaction_region(const ShenandoahHeapRegion* r) {
-  HeapWord* next_addr = r->bottom() + ShenandoahHeapRegion::RegionSizeBytes / HeapWordSize;
-  ShenandoahHeapRegion* next = heap_region_containing(next_addr);
-  if (next->is_humongous()) {
-    return next_compaction_region(next);
-  } else {
-    return next;
+  int region_idx = r->region_number() + 1;
+  ShenandoahHeapRegion* next = _ordered_regions[region_idx];
+  guarantee(next->region_number() == region_idx, "region number must match");
+  while (next->is_humongous()) {
+    region_idx = next->region_number() + 1;
+    next = _ordered_regions[region_idx];
+    guarantee(next->region_number() == region_idx, "region number must match");
   }
+  return next;
 }
--- a/src/share/vm/gc/shenandoah/shenandoahHeap.hpp	Wed Sep 16 17:22:25 2015 +0200
+++ b/src/share/vm/gc/shenandoah/shenandoahHeap.hpp	Fri Sep 18 15:44:29 2015 +0200
@@ -315,8 +315,6 @@
   static ByteSize ordered_regions_offset() { return byte_offset_of(ShenandoahHeap, _ordered_regions); }
   static ByteSize first_region_bottom_offset() { return byte_offset_of(ShenandoahHeap, _first_region_bottom); }
 
-  // Where the first object may be placed.
-  HeapWord* start_of_heap() { return _first_region_bottom + 1;}
   void cleanup_after_cancelconcgc();
   void increase_used(size_t bytes);
   void decrease_used(size_t bytes);
--- a/src/share/vm/gc/shenandoah/shenandoahHeapRegion.cpp	Wed Sep 16 17:22:25 2015 +0200
+++ b/src/share/vm/gc/shenandoah/shenandoahHeapRegion.cpp	Fri Sep 18 15:44:29 2015 +0200
@@ -29,7 +29,7 @@
   return JNI_OK;
 }
 
-int ShenandoahHeapRegion::region_number() {
+int ShenandoahHeapRegion::region_number() const {
   return _region_number;
 }
 
--- a/src/share/vm/gc/shenandoah/shenandoahHeapRegion.hpp	Wed Sep 16 17:22:25 2015 +0200
+++ b/src/share/vm/gc/shenandoah/shenandoahHeapRegion.hpp	Fri Sep 18 15:44:29 2015 +0200
@@ -70,7 +70,7 @@
   jint initialize_heap_region(HeapWord* start, size_t regionSize, int index);
 
 
-  int region_number();
+  int region_number() const;
 
   // Roll back the previous allocation of an object with specified size.
   // Returns TRUE when successful, FALSE if not successful or not supported.
--- a/src/share/vm/gc/shenandoah/shenandoahMarkCompact.cpp	Wed Sep 16 17:22:25 2015 +0200
+++ b/src/share/vm/gc/shenandoah/shenandoahMarkCompact.cpp	Fri Sep 18 15:44:29 2015 +0200
@@ -28,6 +28,9 @@
 }
 
 void ShenandoahMarkCompact::do_mark_compact() {
+
+  COMPILER2_PRESENT(DerivedPointerTable::clear());
+
   ShenandoahHeap* _heap = ShenandoahHeap::heap();
 
   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
@@ -137,6 +140,8 @@
 
   _heap->set_need_update_refs(false);
 
+  COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
+
   _heap->shenandoahPolicy()->record_phase_end(ShenandoahCollectorPolicy::full_gc);
 }
 
@@ -187,6 +192,10 @@
     UpdateRefsClosure uprefs;
     CLDToOopClosure cld_uprefs(&uprefs);
     ClassLoaderDataGraph::roots_cld_do(NULL, &cld_uprefs);
+
+    // Same for weak JNI handles.
+    ShenandoahAlwaysTrueClosure always_true;
+    JNIHandles::weak_oops_do(&always_true, &uprefs);
   }
  
   _heap->shenandoahPolicy()->record_phase_start(ShenandoahCollectorPolicy::weakrefs);
@@ -259,7 +268,7 @@
     if (!r->is_humongous()) {
       if (_cp.space == NULL) {
 	_cp.space = r;
-	_cp.threshold = _heap->start_of_heap();
+	_cp.threshold = r->initialize_threshold();
       }
       _dead_humongous = false;
       r->prepare_for_compaction(&_cp);
@@ -272,15 +281,21 @@
 	} else {
 	  if (_cp.space == NULL) {
 	    _cp.space = r;
-	    _cp.threshold = _heap->start_of_heap();
+	    _cp.threshold = r->initialize_threshold();
 	  }
 	  _dead_humongous = true;
+	  guarantee(r->region_number() > ((ShenandoahHeapRegion*)_cp.space)->region_number(),
+		    "only reset regions that are not yet used for compaction");
 	  r->reset();
+	  r->prepare_for_compaction(&_cp);
 	}
       } else {
 	assert(r->is_humongous_continuation(), "expect humongous continuation");
 	if (_dead_humongous) {
+	  guarantee(r->region_number() > ((ShenandoahHeapRegion*)_cp.space)->region_number(),
+		    "only reset regions that are not yet used for compaction");
 	  r->reset();
+	  r->prepare_for_compaction(&_cp);
 	}
       }
     }