backport 692bedbc1df153f362b8e85693f20b089b5594e2

Author: GoeLin

src/hotspot/share/prims/jniCheck.cpp

@@ -46,9 +46,6 @@
 #include "utilities/formatBuffer.hpp"
 #include "utilities/utf8.hpp"
 
-// Complain every extra number of unplanned local refs
-#define CHECK_JNI_LOCAL_REF_CAP_WARN_THRESHOLD 32
-
 // Heap objects are allowed to be directly referenced only in VM code,
 // not in native code.
 
@@ -202,17 +199,6 @@ check_pending_exception(JavaThread* thr) {
   }
 }
 
-/**
- * Add to the planned number of handles. I.e. plus current live & warning threshold
- */
-static inline void
-add_planned_handle_capacity(JNIHandleBlock* handles, size_t capacity) {
-  handles->set_planned_capacity(capacity +
-                                handles->get_number_of_live_handles() +
-                                CHECK_JNI_LOCAL_REF_CAP_WARN_THRESHOLD);
-}
-
-
 static inline void
 functionEnterCritical(JavaThread* thr)
 {
@@ -244,18 +230,7 @@ functionEnterExceptionAllowed(JavaThread* thr)
 static inline void
 functionExit(JavaThread* thr)
 {
-  JNIHandleBlock* handles = thr->active_handles();
-  size_t planned_capacity = handles->get_planned_capacity();
-  size_t live_handles = handles->get_number_of_live_handles();
-  if (live_handles > planned_capacity) {
-    IN_VM(
-      tty->print_cr("WARNING: JNI local refs: " SIZE_FORMAT ", exceeds capacity: " SIZE_FORMAT,
-                    live_handles, planned_capacity);
-      thr->print_stack();
-    )
-    // Complain just the once, reset to current + warn threshold
-    add_planned_handle_capacity(handles, 0);
-  }
+  // No checks at this time
 }
 
 static inline void
@@ -746,9 +721,6 @@ JNI_ENTRY_CHECKED(jint,
     if (capacity < 0)
       NativeReportJNIFatalError(thr, "negative capacity");
     jint result = UNCHECKED()->PushLocalFrame(env, capacity);
-    if (result == JNI_OK) {
-      add_planned_handle_capacity(thr->active_handles(), capacity);
-    }
     functionExit(thr);
     return result;
 JNI_END
@@ -850,12 +822,6 @@ JNI_ENTRY_CHECKED(jint,
       NativeReportJNIFatalError(thr, "negative capacity");
     }
     jint result = UNCHECKED()->EnsureLocalCapacity(env, capacity);
-    if (result == JNI_OK) {
-      // increase local ref capacity if needed
-      if ((size_t)capacity > thr->active_handles()->get_planned_capacity()) {
-        add_planned_handle_capacity(thr->active_handles(), capacity);
-      }
-    }
     functionExit(thr);
     return result;
 JNI_END

src/hotspot/share/runtime/jniHandles.cpp

@@ -385,7 +385,6 @@ JNIHandleBlock* JNIHandleBlock::allocate_block(Thread* thread, AllocFailType all
   block->_top = 0;
   block->_next = NULL;
   block->_pop_frame_link = NULL;
-  block->_planned_capacity = block_size_in_oops;
   // _last, _free_list & _allocate_before_rebuild initialized in allocate_handle
   debug_only(block->_last = NULL);
   debug_only(block->_free_list = NULL);
@@ -591,22 +590,6 @@ size_t JNIHandleBlock::length() const {
   return result;
 }
 
-class CountJNIHandleClosure: public OopClosure {
-private:
-  int _count;
-public:
-  CountJNIHandleClosure(): _count(0) {}
-  virtual void do_oop(oop* ooph) { _count++; }
-  virtual void do_oop(narrowOop* unused) { ShouldNotReachHere(); }
-  int count() { return _count; }
-};
-
-const size_t JNIHandleBlock::get_number_of_live_handles() {
-  CountJNIHandleClosure counter;
-  oops_do(&counter);
-  return counter.count();
-}
-
 // This method is not thread-safe, i.e., must be called while holding a lock on the
 // structure.
 size_t JNIHandleBlock::memory_usage() const {

src/hotspot/share/runtime/jniHandles.hpp

@@ -193,11 +193,6 @@ class JNIHandleBlock : public CHeapObj<mtInternal> {
   // Traversal of handles
   void oops_do(OopClosure* f);
 
-  // Checked JNI support
-  void set_planned_capacity(size_t planned_capacity) { _planned_capacity = planned_capacity; }
-  const size_t get_planned_capacity() { return _planned_capacity; }
-  const size_t get_number_of_live_handles();
-
   // Debugging
   bool chain_contains(jobject handle) const;    // Does this block or following blocks contain handle
   bool contains(jobject handle) const;          // Does this block contain handle

src/java.base/share/man/java.1

@@ -843,10 +843,6 @@ A JNI call was made without checking for a pending exception from a
 previous JNI call, and the current call is not safe when an exception
 may be pending.
 .IP \[bu] 2
-The number of JNI local references existing when a JNI function
-terminates exceeds the number guaranteed to be available.
-See the \f[CB]EnsureLocalcapacity\f[R] function.
-.IP \[bu] 2
 A class descriptor is in decorated format (\f[CB]Lname;\f[R]) when it
 should not be.
 .IP \[bu] 2

test/hotspot/jtreg/runtime/jni/checked/TestCheckedEnsureLocalCapacity.java

@@ -750,7 +750,6 @@ tools/jlink/plugins/CompressorPluginTest.java                   8247407 generic-
 ############################################################################
 
 # core_svc
-tools/launcher/TestXcheckJNIWarnings.java#jdwp-agent   8296936 generic-all
 
 ############################################################################