8357086: Addressed reviewer's comments

Author: toxaart

src/hotspot/os/linux/os_linux.cpp

@@ -294,7 +294,9 @@ bool os::Linux::free_memory(size_t& value) {
 bool os::total_swap_space(size_t& value) {
   if (OSContainer::is_containerized() && OSContainer::memory_and_swap_limit_in_bytes() > 0) {
     if (OSContainer::memory_limit_in_bytes() > 0) {
-      value = static_cast<size_t>(OSContainer::memory_and_swap_limit_in_bytes() - OSContainer::memory_limit_in_bytes());
+      jlong memory_and_swap_limit_in_bytes = OSContainer::memory_and_swap_limit_in_bytes();
+      jlong memory_limit_in_bytes = OSContainer::memory_limit_in_bytes();
+      value = static_cast<size_t>(memory_and_swap_limit_in_bytes - memory_limit_in_bytes);
       return true;
     }
   } // fallback to the host swap space if the container did return the unbound value of -1

src/hotspot/os/windows/os_windows.cpp

@@ -862,35 +862,41 @@ bool os::win32::available_memory(size_t& value) {
   MEMORYSTATUSEX ms;
   ms.dwLength = sizeof(ms);
   BOOL res = GlobalMemoryStatusEx(&ms);
-  if (res) {
+  if (res == TRUE) {
     value = static_cast<size_t>(ms.ullAvailPhys);
     return true;
   } else {
-    return false;
+    errno = ::GetLastError();
+    log_debug(os)("available_memory() failed to GlobalMemoryStatusEx: GetLastError->%ld.", errno);
+    return res == TRUE;
   }
 }
 
 bool os::total_swap_space(size_t& value) {
   MEMORYSTATUSEX ms;
   ms.dwLength = sizeof(ms);
   BOOL res = GlobalMemoryStatusEx(&ms);
-  if (res) {
+  if (res == TRUE) {
     value = static_cast<size_t>(ms.ullTotalPageFile);
     return true;
   } else {
-    return false;
+    errno = ::GetLastError();
+    log_debug(os)("total_swap_space() failed to GlobalMemoryStatusEx: GetLastError->%ld.", errno);
+    return res == TRUE;
   }
 }
 
 bool os::free_swap_space(size_t& value) {
   MEMORYSTATUSEX ms;
   ms.dwLength = sizeof(ms);
   BOOL res = GlobalMemoryStatusEx(&ms);
-  if (res) {
+  if (res == TRUE) {
     value = static_cast<size_t>(ms.ullAvailPageFile);
     return true;
   } else {
-    return false;
+    errno = ::GetLastError();
+    log_debug(os)("free_swap_space() failed to GlobalMemoryStatusEx: GetLastError->%ld.", errno);
+    return res == TRUE;
   }
 }
 

src/hotspot/share/jfr/jni/jfrJniMethod.cpp

@@ -414,8 +414,7 @@ JVM_ENTRY_NO_ENV(jlong, jfr_host_total_memory(JNIEnv* env, jclass jvm))
   // os::physical_memory() would return the container limit.
   return os::Linux::physical_memory();
 #else
-  size_t phys_mem = os::physical_memory();
-  return static_cast<jlong>(phys_mem);
+  return static_cast<jlong>(os::physical_memory());
 #endif
 JVM_END
 

src/hotspot/share/jfr/periodic/jfrPeriodic.cpp

@@ -528,11 +528,11 @@ TRACE_REQUEST_FUNC(ThreadAllocationStatistics) {
  *  the total memory reported is the amount of memory configured for the guest OS by the hypervisor.
  */
 TRACE_REQUEST_FUNC(PhysicalMemory) {
-  size_t phys_mem = os::physical_memory();
-  u8 totalPhysicalMemory = static_cast<u8>(phys_mem);
+  u8 totalPhysicalMemory = static_cast<u8>(os::physical_memory());
   EventPhysicalMemory event;
   event.set_totalSize(totalPhysicalMemory);
   size_t avail_mem = 0;
+  // Return value ignored - defaulting to 0 on failure.
   (void)os::available_memory(avail_mem);
   event.set_usedSize(totalPhysicalMemory - static_cast<u8>(avail_mem));
   event.commit();
@@ -541,9 +541,11 @@ TRACE_REQUEST_FUNC(PhysicalMemory) {
 TRACE_REQUEST_FUNC(SwapSpace) {
   EventSwapSpace event;
   size_t total_swap_space = 0;
+  // Return value ignored - defaulting to 0 on failure.
   (void)os::total_swap_space(total_swap_space);
   event.set_totalSize(static_cast<s8>(total_swap_space));
   size_t free_swap_space = 0;
+  // Return value ignored - defaulting to 0 on failure.
   (void)os::free_swap_space(free_swap_space);
   event.set_freeSize(static_cast<s8>(free_swap_space));
   event.commit();

src/hotspot/share/prims/jvmtiRedefineClasses.cpp

@@ -1359,6 +1359,7 @@ jvmtiError VM_RedefineClasses::load_new_class_versions() {
     HandleMark hm(current);
     InstanceKlass* the_class = get_ik(_class_defs[i].klass);
     size_t avail_mem = 0;
+    // Return value ignored - defaulting to 0 on failure.
     (void)os::available_memory(avail_mem);
     log_debug(redefine, class, load)
       ("loading name=%s kind=%d (avail_mem=%zuK)",
@@ -1526,6 +1527,7 @@ jvmtiError VM_RedefineClasses::load_new_class_versions() {
         return JVMTI_ERROR_INTERNAL;
       }
     }
+    // Return value ignored - defaulting to 0 on failure.
     (void)os::available_memory(avail_mem);
     log_debug(redefine, class, load)
       ("loaded name=%s (avail_mem=%zuK)", the_class->external_name(), avail_mem >> 10);
@@ -4437,6 +4439,7 @@ void VM_RedefineClasses::redefine_single_class(Thread* current, jclass the_jclas
     // increment the classRedefinedCount field in the_class and in any
     // direct and indirect subclasses of the_class
     size_t avail_mem = 0;
+    // Return value ignored - defaulting to 0 on failure.
     (void)os::available_memory(avail_mem);
     log_info(redefine, class, load)
       ("redefined name=%s, count=%d (avail_mem=%zuK)",

src/hotspot/share/prims/whitebox.cpp

@@ -2512,8 +2512,7 @@ WB_END
 // Physical memory of the host machine (including containers)
 WB_ENTRY(jlong, WB_HostPhysicalMemory(JNIEnv* env, jobject o))
   LINUX_ONLY(return static_cast<jlong>(os::Linux::physical_memory());)
-  size_t phys_mem = os::physical_memory();
-  return static_cast<jlong>(phys_mem);
+  return static_cast<jlong>(os::physical_memory());
 WB_END
 
 // Available memory of the host machine (container-aware)

src/hotspot/share/services/heapDumper.cpp

@@ -2613,6 +2613,7 @@ int HeapDumper::dump(const char* path, outputStream* out, int compression, bool
     // For the OOM handling we may already be limited in memory.
     // Lets ensure we have at least 20MB per thread.
     size_t free_memory = 0;
+    // Return value ignored - defaulting to 0 on failure.
     (void)os::free_memory(free_memory);
     julong max_threads = free_memory / (20 * M);
     if (num_dump_threads > max_threads) {