src/os/linux/vm/os_linux.cpp

rev 2869 : 7117303: VM uses non-monotonic time source and complains that it is non-monotonic
Summary: Replaces calls to os::javaTimeMillis(), which does not guarantee montonicity, in GC code to os::javaTimeNanos() with a suitable conversion factor. os::javaTimeNanos() mostly guarantees montonicity depending on the underlying OS implementation and, as a result, a better alternative. Changes in OS files are to make use of the newly defined constants in globalDefinitions.hpp.
Reviewed-by:

@@ -125,11 +125,10 @@
 
 #define MAX_PATH    (2 * K)
 
 // for timer info max values which include all bits
 #define ALL_64_BITS CONST64(0xFFFFFFFFFFFFFFFF)
-#define SEC_IN_NANOSECS  1000000000LL
 
 #define LARGEPAGES_BIT (1 << 6)
 ////////////////////////////////////////////////////////////////////////////////
 // global variables
 julong os::Linux::_physical_memory = 0;

@@ -3257,12 +3256,10 @@
 // Solaris uses poll(), linux uses park().
 // Poll() is likely a better choice, assuming that Thread.interrupt()
 // generates a SIGUSRx signal. Note that SIGUSR1 can interfere with
 // SIGSEGV, see 4355769.
 
-const int NANOSECS_PER_MILLISECS = 1000000;
-
 int os::sleep(Thread* thread, jlong millis, bool interruptible) {
   assert(thread == Thread::current(),  "thread consistency check");
 
   ParkEvent * const slp = thread->_SleepEvent ;
   slp->reset() ;

@@ -3281,11 +3278,11 @@
       if (newtime - prevtime < 0) {
         // time moving backwards, should only happen if no monotonic clock
         // not a guarantee() because JVM should not abort on kernel/glibc bugs
         assert(!Linux::supports_monotonic_clock(), "time moving backwards");
       } else {
-        millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
+        millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
       }
 
       if(millis <= 0) {
         return OS_OK;
       }

@@ -3320,11 +3317,11 @@
       if (newtime - prevtime < 0) {
         // time moving backwards, should only happen if no monotonic clock
         // not a guarantee() because JVM should not abort on kernel/glibc bugs
         assert(!Linux::supports_monotonic_clock(), "time moving backwards");
       } else {
-        millis -= (newtime - prevtime) / NANOSECS_PER_MILLISECS;
+        millis -= (newtime - prevtime) / NANOSECS_PER_MILLISEC;
       }
 
       if(millis <= 0) break ;
 
       prevtime = newtime;

@@ -3922,11 +3919,11 @@
 jlong os::Linux::fast_thread_cpu_time(clockid_t clockid) {
   struct timespec tp;
   int rc = os::Linux::clock_gettime(clockid, &tp);
   assert(rc == 0, "clock_gettime is expected to return 0 code");
 
-  return (tp.tv_sec * SEC_IN_NANOSECS) + tp.tv_nsec;
+  return (tp.tv_sec * NANOSECS_PER_SEC) + tp.tv_nsec;
 }
 
 /////
 // glibc on Linux platform uses non-documented flag
 // to indicate, that some special sort of signal

@@ -5163,13 +5160,10 @@
  * on the condvar. Contention seen when trying to park implies that someone
  * is unparking you, so don't wait. And spurious returns are fine, so there
  * is no need to track notifications.
  */
 
-
-#define NANOSECS_PER_SEC 1000000000
-#define NANOSECS_PER_MILLISEC 1000000
 #define MAX_SECS 100000000
 /*
  * This code is common to linux and solaris and will be moved to a
  * common place in dolphin.
  *