diff src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp @ 20331:18bf0b66de52

8044406: JVM crash with JDK8 (build 1.8.0-b132) with G1 GC Summary: Fill the last card that has been allocated into with a dummy object Reviewed-by: tschatzl, mgerdin
author poonam
date Tue, 19 Aug 2014 02:05:49 -0700
parents bfba6779654b
children ff3169f25621
line wrap: on
line diff
--- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Wed Aug 13 17:37:11 2014 -0700
+++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Tue Aug 19 02:05:49 2014 -0700
@@ -7053,6 +7053,35 @@
   _g1h->retire_gc_alloc_region(alloc_region, allocated_bytes,
                                GCAllocForTenured);
 }
+
+HeapRegion* OldGCAllocRegion::release() {
+  HeapRegion* cur = get();
+  if (cur != NULL) {
+    // Determine how far we are from the next card boundary. If it is smaller than
+    // the minimum object size we can allocate into, expand into the next card.
+    HeapWord* top = cur->top();
+    HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, G1BlockOffsetSharedArray::N_bytes);
+
+    size_t to_allocate_words = pointer_delta(aligned_top, top, HeapWordSize);
+
+    if (to_allocate_words != 0) {
+      // We are not at a card boundary. Fill up, possibly into the next, taking the
+      // end of the region and the minimum object size into account.
+      to_allocate_words = MIN2(pointer_delta(cur->end(), cur->top(), HeapWordSize),
+                               MAX2(to_allocate_words, G1CollectedHeap::min_fill_size()));
+
+      // Skip allocation if there is not enough space to allocate even the smallest
+      // possible object. In this case this region will not be retained, so the
+      // original problem cannot occur.
+      if (to_allocate_words >= G1CollectedHeap::min_fill_size()) {
+        HeapWord* dummy = attempt_allocation(to_allocate_words, true /* bot_updates */);
+        CollectedHeap::fill_with_object(dummy, to_allocate_words);
+      }
+    }
+  }
+  return G1AllocRegion::release();
+}
+
 // Heap region set verification
 
 class VerifyRegionListsClosure : public HeapRegionClosure {