Reset BlockZeroingLowLimit to 4 * _zva_length

Signed-off-by: Patrick Zhang <[email protected]>

Author: cnqpzhang

src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp

@@ -6261,7 +6261,12 @@ address MacroAssembler::zero_words(Register base, uint64_t cnt)
 {
   assert(wordSize <= BlockZeroingLowLimit, "increase BlockZeroingLowLimit");
   address result = nullptr;
-  if (UseBlockZeroing && cnt > (uint64_t)BlockZeroingLowLimit / BytesPerWord) {
+  // We do not check UseBlockZeroing here because this is delegated to the
+  // zero_blocks stub function that wraps the core logic of zero_words
+  // and necessary unrolled str/stp expanding when the condition is not met.
+  // This approach also helps prevent sudden increases in code cache size
+  // when zeroing large memory areas in many places.
+  if (cnt > (uint64_t)BlockZeroingLowLimit / BytesPerWord) {
     mov(r10, base); mov(r11, cnt);
     result = zero_words(r10, r11);
   } else {

src/hotspot/cpu/aarch64/vm_version_aarch64.cpp

@@ -454,7 +454,8 @@ void VM_Version::initialize() {
     FLAG_SET_DEFAULT(UseBlockZeroing, false);
   }
   if (!UseBlockZeroing && !FLAG_IS_DEFAULT(BlockZeroingLowLimit)) {
-    warning("BlockZeroingLowLimit will not work when UseBlockZeroing is false");
+    warning("BlockZeroingLowLimit has been ignored because UseBlockZeroing is disabled");
+    FLAG_SET_DEFAULT(BlockZeroingLowLimit, 4 * VM_Version::zva_length());
   }
 
   if (VM_Version::supports_sve2()) {