src/share/vm/memory/threadLocalAllocBuffer.cpp

rev 11944 : 8231779: crash HeapWord*ParallelScavengeHeap::failed_mem_allocate
Reviewed-by: dlong, tschatzl, pliden
rev 11952 : Merge jdk8u272-b02

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2020, 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.

@@ -88,11 +88,12 @@
       // _gc_waste is not subtracted because it's included in
       // "used".
       // The result can be larger than 1.0 due to direct to old allocations.
       // These allocations should ideally not be counted but since it is not possible
       // to filter them out here we just cap the fraction to be at most 1.0.
-      double alloc_frac = MIN2(1.0, (double) allocated_since_last_gc / used);
+      // Keep alloc_frac as float and not double to avoid the double to float conversion
+      float alloc_frac = MIN2(1.0f, allocated_since_last_gc / (float) used);
       _allocation_fraction.sample(alloc_frac);
     }
     global_stats()->update_allocating_threads();
     global_stats()->update_number_of_refills(_number_of_refills);
     global_stats()->update_allocation(_number_of_refills * desired_size());

@@ -211,11 +212,12 @@
   // Following check is needed because at startup the main
   // thread is initialized before the heap is.  The initialization for
   // this thread is redone in startup_initialization below.
   if (Universe::heap() != NULL) {
     size_t capacity   = Universe::heap()->tlab_capacity(myThread()) / HeapWordSize;
-    double alloc_frac = desired_size() * target_refills() / (double) capacity;
+    // Keep alloc_frac as float and not double to avoid the double to float conversion
+    float alloc_frac = desired_size() * target_refills() / (float) capacity;
     _allocation_fraction.sample(alloc_frac);
   }
 
   set_refill_waste_limit(initial_refill_waste_limit());