8315242: G1: Fix -Wconversion warnings around GCDrainStackTargetSize

Reviewed-by: tschatzl, mli

Author: albertnetymk

src/hotspot/share/gc/g1/g1ConcurrentMark.cpp

@@ -2317,9 +2317,9 @@ void G1CMTask::drain_local_queue(bool partially) {
   // Decide what the target size is, depending whether we're going to
   // drain it partially (so that other tasks can steal if they run out
   // of things to do) or totally (at the very end).
-  size_t target_size;
+  uint target_size;
   if (partially) {
-    target_size = MIN2((size_t)_task_queue->max_elems()/3, GCDrainStackTargetSize);
+    target_size = MIN2(_task_queue->max_elems() / 3, GCDrainStackTargetSize);
   } else {
     target_size = 0;
   }

src/hotspot/share/gc/parallel/psPromotionManager.cpp

@@ -178,15 +178,13 @@ PSPromotionManager::PSPromotionManager() {
   // We set the old lab's start array.
   _old_lab.set_start_array(old_gen()->start_array());
 
-  uint queue_size;
-  queue_size = claimed_stack_depth()->max_elems();
+  uint queue_size = claimed_stack_depth()->max_elems();
 
   if (ParallelGCThreads == 1) {
     _target_stack_size = 0;
   } else {
     // don't let the target stack size to be more than 1/4 of the entries
-    _target_stack_size = (uint) MIN2((uint) GCDrainStackTargetSize,
-                                     (uint) (queue_size / 4));
+    _target_stack_size = MIN2(GCDrainStackTargetSize, (queue_size / 4));
   }
 
   _array_chunk_size = ParGCArrayScanChunk;

src/hotspot/share/gc/shared/gc_globals.hpp

@@ -684,10 +684,10 @@
   develop(uintx, GCExpandToAllocateDelayMillis, 0,                          \
           "Delay between expansion and allocation (in milliseconds)")       \
                                                                             \
-  product(uintx, GCDrainStackTargetSize, 64,                                \
+  product(uint, GCDrainStackTargetSize, 64,                                 \
           "Number of entries we will try to leave on the stack "            \
           "during parallel gc")                                             \
-          range(0, max_juint)                                               \
+          range(0, (UINT_MAX - 1) / 2)                                      \
                                                                             \
   product(uint, GCCardSizeInBytes, 512,                                     \
           "Card table entry size (in bytes) for card based collectors")     \

src/hotspot/share/utilities/globalDefinitions.hpp

@@ -1044,7 +1044,7 @@ const int      badCodeHeapFreeVal = 0xDD;                   // value used to zap
 #define       badHeapWord       (::badHeapWordVal)
 
 // Default TaskQueue size is 16K (32-bit) or 128K (64-bit)
-const size_t TASKQUEUE_SIZE = (NOT_LP64(1<<14) LP64_ONLY(1<<17));
+const uint TASKQUEUE_SIZE = (NOT_LP64(1<<14) LP64_ONLY(1<<17));
 
 //----------------------------------------------------------------------------------------------------
 // Utility functions for bitfield manipulations