# HG changeset patch
# User cjplummer
# Date 1415221259 28800
# Node ID 07948a5f8f5c45ef4b8e413ee89574d9da27a664
# Parent  cdc1d5bc86cf69e4b5103d5b64ddac3eab256f91
8043770: File leak in MemNotifyThread::start() in hotspot.src.os.linux.vm.os_linux.cpp
Summary: Fixed by removing all code related to LowMemoryProtection, which removed offending code.
Reviewed-by: dholmes, minqi

diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/os/aix/vm/os_aix.cpp
--- a/hotspot/src/os/aix/vm/os_aix.cpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/os/aix/vm/os_aix.cpp	Wed Nov 05 13:00:59 2014 -0800
@@ -3829,11 +3829,6 @@
   return JNI_OK;
 }
 
-// this is called at the end of vm_initialization
-void os::init_3(void) {
-  return;
-}
-
 // Mark the polling page as unreadable
 void os::make_polling_page_unreadable(void) {
   if (!guard_memory((char*)_polling_page, Aix::page_size())) {
diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/os/bsd/vm/os_bsd.cpp
--- a/hotspot/src/os/bsd/vm/os_bsd.cpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/os/bsd/vm/os_bsd.cpp	Wed Nov 05 13:00:59 2014 -0800
@@ -3635,9 +3635,6 @@
   return JNI_OK;
 }
 
-// this is called at the end of vm_initialization
-void os::init_3(void) { }
-
 // Mark the polling page as unreadable
 void os::make_polling_page_unreadable(void) {
   if (!guard_memory((char*)_polling_page, Bsd::page_size())) {
diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/os/linux/vm/os_linux.cpp
--- a/hotspot/src/os/linux/vm/os_linux.cpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/os/linux/vm/os_linux.cpp	Wed Nov 05 13:00:59 2014 -0800
@@ -163,35 +163,6 @@
 // Declarations
 static void unpackTime(timespec* absTime, bool isAbsolute, jlong time);
 
-#ifdef JAVASE_EMBEDDED
-class MemNotifyThread: public Thread {
-  friend class VMStructs;
- public:
-  virtual void run();
-
- private:
-  static MemNotifyThread* _memnotify_thread;
-  int _fd;
-
- public:
-
-  // Constructor
-  MemNotifyThread(int fd);
-
-  // Tester
-  bool is_memnotify_thread() const { return true; }
-
-  // Printing
-  char* name() const { return (char*)"Linux MemNotify Thread"; }
-
-  // Returns the single instance of the MemNotifyThread
-  static MemNotifyThread* memnotify_thread() { return _memnotify_thread; }
-
-  // Create and start the single instance of MemNotifyThread
-  static void start();
-};
-#endif // JAVASE_EMBEDDED
-
 // utility functions
 
 static int SR_initialize();
@@ -4866,17 +4837,6 @@
   return JNI_OK;
 }
 
-// this is called at the end of vm_initialization
-void os::init_3(void) {
-#ifdef JAVASE_EMBEDDED
-  // Start the MemNotifyThread
-  if (LowMemoryProtection) {
-    MemNotifyThread::start();
-  }
-  return;
-#endif
-}
-
 // Mark the polling page as unreadable
 void os::make_polling_page_unreadable(void) {
   if (!guard_memory((char*)_polling_page, Linux::page_size())) {
@@ -6033,82 +5993,6 @@
   return strlen(buffer);
 }
 
-#ifdef JAVASE_EMBEDDED
-//
-// A thread to watch the '/dev/mem_notify' device, which will tell us when the OS is running low on memory.
-//
-MemNotifyThread* MemNotifyThread::_memnotify_thread = NULL;
-
-// ctor
-//
-MemNotifyThread::MemNotifyThread(int fd): Thread() {
-  assert(memnotify_thread() == NULL, "we can only allocate one MemNotifyThread");
-  _fd = fd;
-
-  if (os::create_thread(this, os::os_thread)) {
-    _memnotify_thread = this;
-    os::set_priority(this, NearMaxPriority);
-    os::start_thread(this);
-  }
-}
-
-// Where all the work gets done
-//
-void MemNotifyThread::run() {
-  assert(this == memnotify_thread(), "expected the singleton MemNotifyThread");
-
-  // Set up the select arguments
-  fd_set rfds;
-  if (_fd != -1) {
-    FD_ZERO(&rfds);
-    FD_SET(_fd, &rfds);
-  }
-
-  // Now wait for the mem_notify device to wake up
-  while (1) {
-    // Wait for the mem_notify device to signal us..
-    int rc = select(_fd+1, _fd != -1 ? &rfds : NULL, NULL, NULL, NULL);
-    if (rc == -1) {
-      perror("select!\n");
-      break;
-    } else if (rc) {
-      //ssize_t free_before = os::available_memory();
-      //tty->print ("Notified: Free: %dK \n",os::available_memory()/1024);
-
-      // The kernel is telling us there is not much memory left...
-      // try to do something about that
-
-      // If we are not already in a GC, try one.
-      if (!Universe::heap()->is_gc_active()) {
-        Universe::heap()->collect(GCCause::_allocation_failure);
-
-        //ssize_t free_after = os::available_memory();
-        //tty->print ("Post-Notify: Free: %dK\n",free_after/1024);
-        //tty->print ("GC freed: %dK\n", (free_after - free_before)/1024);
-      }
-      // We might want to do something like the following if we find the GC's are not helping...
-      // Universe::heap()->size_policy()->set_gc_time_limit_exceeded(true);
-    }
-  }
-}
-
-// See if the /dev/mem_notify device exists, and if so, start a thread to monitor it.
-//
-void MemNotifyThread::start() {
-  int fd;
-  fd = open("/dev/mem_notify", O_RDONLY, 0);
-  if (fd < 0) {
-    return;
-  }
-
-  if (memnotify_thread() == NULL) {
-    new MemNotifyThread(fd);
-  }
-}
-
-#endif // JAVASE_EMBEDDED
-
-
 /////////////// Unit tests ///////////////
 
 #ifndef PRODUCT
diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/os/solaris/vm/os_solaris.cpp
--- a/hotspot/src/os/solaris/vm/os_solaris.cpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/os/solaris/vm/os_solaris.cpp	Wed Nov 05 13:00:59 2014 -0800
@@ -4761,10 +4761,6 @@
   return JNI_OK;
 }
 
-void os::init_3(void) {
-  return;
-}
-
 // Mark the polling page as unreadable
 void os::make_polling_page_unreadable(void) {
   if (mprotect((char *)_polling_page, page_size, PROT_NONE) != 0) {
diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/os/windows/vm/os_windows.cpp
--- a/hotspot/src/os/windows/vm/os_windows.cpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/os/windows/vm/os_windows.cpp	Wed Nov 05 13:00:59 2014 -0800
@@ -4140,10 +4140,6 @@
   return JNI_OK;
 }
 
-void os::init_3(void) {
-  return;
-}
-
 // Mark the polling page as unreadable
 void os::make_polling_page_unreadable(void) {
   DWORD old_status;
diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/share/vm/runtime/globals.hpp
--- a/hotspot/src/share/vm/runtime/globals.hpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/share/vm/runtime/globals.hpp	Wed Nov 05 13:00:59 2014 -0800
@@ -2066,9 +2066,6 @@
           "Provide more detailed and expensive TLAB statistics "            \
           "(with PrintTLAB)")                                               \
                                                                             \
-  EMBEDDED_ONLY(product(bool, LowMemoryProtection, true,                    \
-          "Enable LowMemoryProtection"))                                    \
-                                                                            \
   product_pd(bool, NeverActAsServerClassMachine,                            \
           "Never act like a server-class machine")                          \
                                                                             \
diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/share/vm/runtime/os.hpp
--- a/hotspot/src/share/vm/runtime/os.hpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/share/vm/runtime/os.hpp	Wed Nov 05 13:00:59 2014 -0800
@@ -158,7 +158,6 @@
   static void init_globals(void) {             // Called from init_globals() in init.cpp
     init_globals_ext();
   }
-  static void init_3(void);                    // Called at the end of vm init
 
   // File names are case-insensitive on windows only
   // Override me as needed
diff -r cdc1d5bc86cf -r 07948a5f8f5c hotspot/src/share/vm/runtime/thread.cpp
--- a/hotspot/src/share/vm/runtime/thread.cpp	Mon Nov 03 11:34:13 2014 -0800
+++ b/hotspot/src/share/vm/runtime/thread.cpp	Wed Nov 05 13:00:59 2014 -0800
@@ -3617,9 +3617,6 @@
     }
   }
 
-  // Give os specific code one last chance to start
-  os::init_3();
-
   create_vm_timer.end();
 #ifdef ASSERT
   _vm_complete = true;