src/share/vm/gc/shenandoah/shenandoahHeapRegion.cpp

@@ -277,23 +277,34 @@
 
 void ShenandoahHeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
   uintx region_size;
   if (FLAG_IS_DEFAULT(ShenandoahHeapRegionSize)) {
     if (ShenandoahMinRegionSize > initial_heap_size / MIN_NUM_REGIONS) {
-      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option");
+      err_msg message("Initial heap size (" SIZE_FORMAT "K) is too low to afford the minimum number "
+                      "of regions (" SIZE_FORMAT ") of minimum region size (" SIZE_FORMAT "K).",
+                      initial_heap_size/K, MIN_NUM_REGIONS, ShenandoahMinRegionSize/K);
+      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option", message);
     }
     if (ShenandoahMinRegionSize < MIN_REGION_SIZE) {
-      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option");
+      err_msg message("" SIZE_FORMAT "K should not be lower than minimum region size (" SIZE_FORMAT "K).",
+                      ShenandoahMinRegionSize/K,  MIN_REGION_SIZE/K);
+      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option", message);
     }
     if (ShenandoahMinRegionSize < MinTLABSize) {
-      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option");
+      err_msg message("" SIZE_FORMAT "K should not be lower than TLAB size size (" SIZE_FORMAT "K).",
+                      ShenandoahMinRegionSize/K,  MinTLABSize/K);
+      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option", message);
     }
     if (ShenandoahMaxRegionSize < MIN_REGION_SIZE) {
-      vm_exit_during_initialization("Invalid -XX:ShenandoahMaxRegionSize option");
+      err_msg message("" SIZE_FORMAT "K should not be lower than min region size (" SIZE_FORMAT "K).",
+                      ShenandoahMaxRegionSize/K,  MIN_REGION_SIZE/K);
+      vm_exit_during_initialization("Invalid -XX:ShenandoahMaxRegionSize option", message);
     }
     if (ShenandoahMinRegionSize > ShenandoahMaxRegionSize) {
-      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize or -XX:ShenandoahMaxRegionSize");
+      err_msg message("Minimum (" SIZE_FORMAT "K) should be larger than maximum (" SIZE_FORMAT "K).",
+                      ShenandoahMinRegionSize/K, ShenandoahMaxRegionSize/K);
+      vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize or -XX:ShenandoahMaxRegionSize", message);
     }
     size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
     region_size = MAX2(average_heap_size / ShenandoahTargetNumRegions,
                        ShenandoahMinRegionSize);
 

@@ -301,14 +312,19 @@
     region_size = MAX2(ShenandoahMinRegionSize, region_size);
     region_size = MIN2(ShenandoahMaxRegionSize, region_size);
 
   } else {
     if (ShenandoahHeapRegionSize > initial_heap_size / MIN_NUM_REGIONS) {
-      vm_exit_during_initialization("Invalid -XX:ShenandoahHeapRegionSize option");
+      err_msg message("Initial heap size (" SIZE_FORMAT "K) is too low to afford the minimum number "
+                              "of regions (" SIZE_FORMAT ") of requested size (" SIZE_FORMAT "K).",
+                      initial_heap_size/K, MIN_NUM_REGIONS, ShenandoahHeapRegionSize/K);
+      vm_exit_during_initialization("Invalid -XX:ShenandoahHeapRegionSize option", message);
     }
     if (ShenandoahHeapRegionSize < MIN_REGION_SIZE) {
-      vm_exit_during_initialization("Invalid -XX:ShenandoahHeapRegionSize option");
+      err_msg message("" SIZE_FORMAT " should not be lower than min region size (" SIZE_FORMAT "K).",
+                      ShenandoahHeapRegionSize/K,  MIN_REGION_SIZE/K);
+      vm_exit_during_initialization("Invalid -XX:ShenandoahHeapRegionSize option", message);
     }
     region_size = ShenandoahHeapRegionSize;
   }
 
   // Make sure region size is at least one large page, if enabled.