8315128: jdk/jfr/event/runtime/TestResidentSetSizeEvent.java fails with "The size should be less than or equal to peak"

Reviewed-by: stefank, mgronlun

Author: egahlin

src/hotspot/os/bsd/os_bsd.cpp

@@ -2540,7 +2540,9 @@ void os::jfr_report_memory_info() {
     // Send the RSS JFR event
     EventResidentSetSize event;
     event.set_size(info.resident_size);
-    event.set_peak(info.resident_size_max);
+    // We've seen that resident_size_max sometimes trails resident_size with one page.
+    // Make sure we always report size <= peak
+    event.set_peak(MAX2(info.resident_size_max, info.resident_size));
     event.commit();
   } else {
     // Log a warning