JDK-8293114: JVM should trim the native heap

src/hotspot/os/aix/os_aix.inline.hpp

@@ -52,7 +52,7 @@ inline bool os::must_commit_stack_guard_pages() {
 inline void os::map_stack_shadow_pages(address sp) {
 }
 
-// stubbed-out trim-native support
+// Trim-native support, stubbed out for now, may be enabled later
 inline bool os::can_trim_native_heap() { return false; }
 inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
 

src/hotspot/os/bsd/os_bsd.inline.hpp

@@ -55,7 +55,7 @@ inline bool os::must_commit_stack_guard_pages() {
 inline void os::map_stack_shadow_pages(address sp) {
 }
 
-// stubbed-out trim-native support
+// Trim-native support, stubbed out for now, may be enabled later
 inline bool os::can_trim_native_heap() { return false; }
 inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
 

src/hotspot/os/windows/os_windows.inline.hpp

@@ -93,7 +93,7 @@ inline void PlatformMonitor::notify_all() {
   WakeAllConditionVariable(&_cond);
 }
 
-// stubbed-out trim-native support
+// Trim-native support, stubbed out for now, may be enabled later
 inline bool os::can_trim_native_heap() { return false; }
 inline bool os::trim_native_heap(os::size_change_t* rss_change) { return false; }
 

src/hotspot/share/classfile/stringTable.cpp

@@ -53,6 +53,7 @@
 #include "runtime/mutexLocker.hpp"
 #include "runtime/safepointVerifiers.hpp"
 #include "runtime/timerTrace.hpp"
+#include "runtime/trimNativeHeap.hpp"
 #include "services/diagnosticCommand.hpp"
 #include "utilities/concurrentHashTable.inline.hpp"
 #include "utilities/concurrentHashTableTasks.inline.hpp"
@@ -456,6 +457,7 @@ void StringTable::clean_dead_entries(JavaThread* jt) {
 
   StringTableDeleteCheck stdc;
   StringTableDoDelete stdd;
+  NativeHeapTrimmer::SuspendMark sm("stringtable");
   {
     TraceTime timer("Clean", TRACETIME_LOG(Debug, stringtable, perf));
     while(bdt.do_task(jt, stdc, stdd)) {

src/hotspot/share/classfile/symbolTable.cpp

@@ -37,6 +37,7 @@
 #include "runtime/atomic.hpp"
 #include "runtime/interfaceSupport.inline.hpp"
 #include "runtime/timerTrace.hpp"
+#include "runtime/trimNativeHeap.hpp"
 #include "services/diagnosticCommand.hpp"
 #include "utilities/concurrentHashTable.inline.hpp"
 #include "utilities/concurrentHashTableTasks.inline.hpp"
@@ -737,6 +738,7 @@ void SymbolTable::clean_dead_entries(JavaThread* jt) {
 
   SymbolTableDeleteCheck stdc;
   SymbolTableDoDelete stdd;
+  NativeHeapTrimmer::SuspendMark sm("symboltable");
   {
     TraceTime timer("Clean", TRACETIME_LOG(Debug, symboltable, perf));
     while (bdt.do_task(jt, stdc, stdd)) {

src/hotspot/share/logging/logTag.hpp

@@ -198,6 +198,7 @@ class outputStream;
   LOG_TAG(timer) \
   LOG_TAG(tlab) \
   LOG_TAG(tracking) \
+  LOG_TAG(trimnative) /* trim native heap */ \
   LOG_TAG(unload) /* Trace unloading of classes */ \
   LOG_TAG(unmap) \
   LOG_TAG(unshareable) \

src/hotspot/share/memory/arena.cpp

@@ -30,6 +30,7 @@
 #include "runtime/os.hpp"
 #include "runtime/task.hpp"
 #include "runtime/threadCritical.hpp"
+#include "runtime/trimNativeHeap.hpp"
 #include "services/memTracker.inline.hpp"
 #include "utilities/align.hpp"
 #include "utilities/debug.hpp"
@@ -92,6 +93,7 @@ class ChunkPool {
   }
 
   static void clean() {
+    NativeHeapTrimmer::SuspendMark sm("chunk pool cleaner");
     for (int i = 0; i < _num_pools; i++) {
       _pools[i].prune();
     }

src/hotspot/share/prims/whitebox.cpp

@@ -2580,6 +2580,14 @@ WB_ENTRY(jboolean, WB_SetVirtualThreadsNotifyJvmtiMode(JNIEnv* env, jobject wb,
   return result;
 WB_END
 
+WB_ENTRY(void, WB_PreTouchMemory(JNIEnv* env, jobject wb, jlong addr, jlong size))
+  void* const from = (void*)addr;
+  void* const to = (void*)(addr + size);
+  if (from > to) {
+    os::pretouch_memory(from, to, os::vm_page_size());
+  }
+WB_END
+
 #define CC (char*)
 
 static JNINativeMethod methods[] = {
@@ -2861,6 +2869,7 @@ static JNINativeMethod methods[] = {
   {CC"lockCritical",    CC"()V",                      (void*)&WB_LockCritical},
   {CC"unlockCritical",  CC"()V",                      (void*)&WB_UnlockCritical},
   {CC"setVirtualThreadsNotifyJvmtiMode", CC"(Z)Z",    (void*)&WB_SetVirtualThreadsNotifyJvmtiMode},
+  {CC"preTouchMemory",  CC"(JJ)V",                    (void*)&WB_PreTouchMemory},
 };
 
 

src/hotspot/share/runtime/globals.hpp

@@ -1984,6 +1984,13 @@ const int ObjectAlignmentInBytes = 8;
           "1: monitors & legacy stack-locking (LM_LEGACY, default), "       \
           "2: monitors & new lightweight locking (LM_LIGHTWEIGHT)")         \
           range(0, 2)                                                       \
+                                                                            \
+  product(uint, TrimNativeHeapInterval, 0, EXPERIMENTAL,                    \
+          "Interval, in ms, at which the JVM will trim the native heap if " \
+          "the platform supports that. Lower values will reclaim memory "   \
+          "more eagerly at the cost of higher overhead. A value of 0 "      \
+          "(default) disables the native heap trimming.")                   \
+          range(0, UINT_MAX)                                                \
 
 // end of RUNTIME_FLAGS
 

src/hotspot/share/runtime/java.cpp

@@ -70,6 +70,7 @@
 #include "runtime/task.hpp"
 #include "runtime/threads.hpp"
 #include "runtime/timer.hpp"
+#include "runtime/trimNativeHeap.hpp"
 #include "runtime/vmOperations.hpp"
 #include "runtime/vmThread.hpp"
 #include "runtime/vm_version.hpp"
@@ -479,6 +480,8 @@ void before_exit(JavaThread* thread, bool halt) {
   StatSampler::disengage();
   StatSampler::destroy();
 
+  NativeHeapTrimmer::cleanup();
+
   // Stop concurrent GC threads
   Universe::heap()->stop();
 

src/hotspot/share/runtime/synchronizer.cpp

@@ -54,6 +54,7 @@
 #include "runtime/synchronizer.hpp"
 #include "runtime/threads.hpp"
 #include "runtime/timer.hpp"
+#include "runtime/trimNativeHeap.hpp"
 #include "runtime/vframe.hpp"
 #include "runtime/vmThread.hpp"
 #include "utilities/align.hpp"
@@ -1646,6 +1647,7 @@ class VM_RendezvousGCThreads : public VM_Operation {
 };
 
 static size_t delete_monitors(GrowableArray<ObjectMonitor*>* delete_list) {
+  NativeHeapTrimmer::SuspendMark trim_native_pause("monitor deletion");
   size_t count = 0;
   for (ObjectMonitor* monitor: *delete_list) {
     delete monitor;

src/hotspot/share/runtime/threads.cpp

@@ -87,6 +87,7 @@
 #include "runtime/threadSMR.inline.hpp"
 #include "runtime/timer.hpp"
 #include "runtime/timerTrace.hpp"
+#include "runtime/trimNativeHeap.hpp"
 #include "runtime/vmOperations.hpp"
 #include "runtime/vm_version.hpp"
 #include "services/attachListener.hpp"
@@ -755,6 +756,10 @@ jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
   }
 #endif
 
+  if (NativeHeapTrimmer::enabled()) {
+    NativeHeapTrimmer::initialize();
+  }
+
   // Always call even when there are not JVMTI environments yet, since environments
   // may be attached late and JVMTI must track phases of VM execution
   JvmtiExport::enter_live_phase();