JDK-8324287: Record total and free swap space in JFR

src/hotspot/os/linux/os_linux.cpp

@@ -291,25 +291,30 @@ julong os::Linux::free_memory() {
 
 jlong os::total_swap_space() {
   if (OSContainer::is_containerized()) {
-    return (jlong)(OSContainer::memory_and_swap_limit_in_bytes() - OSContainer::memory_limit_in_bytes());
-  } else {
-    struct sysinfo si;
-    int ret = sysinfo(&si);
-    if (ret != 0) {
-      return -1;
+    if (OSContainer::memory_limit_in_bytes() > 0) {
+      return (jlong)(OSContainer::memory_and_swap_limit_in_bytes() - OSContainer::memory_limit_in_bytes());
     }
-    return  (jlong)(si.totalswap * si.mem_unit);
   }
-}
-
-jlong os::free_swap_space() {
-  // TODO support free swap space in container APIs
   struct sysinfo si;
   int ret = sysinfo(&si);
   if (ret != 0) {
     return -1;
   }
-  return (jlong)(si.freeswap * si.mem_unit);
+  return  (jlong)(si.totalswap * si.mem_unit);
+}
+
+jlong os::free_swap_space() {
+  if (OSContainer::is_containerized()) {
+    // TODO add a good implementation
+    return -1;
+  } else {
+    struct sysinfo si;
+    int ret = sysinfo(&si);
+    if (ret != 0) {
+      return -1;
+    }
+    return (jlong)(si.freeswap * si.mem_unit);
+  }
 }
 
 julong os::physical_memory() {

test/jdk/jdk/jfr/event/os/TestSwapSpaceEvent.java

@@ -50,7 +50,8 @@ public static void main(String[] args) throws Throwable {
         for (RecordedEvent event : events) {
             System.out.println("Event: " + event);
             long totalSize = Events.assertField(event, "totalSize").atLeast(0L).getValue();
-            Events.assertField(event, "freeSize").atLeast(0L).atMost(totalSize);
+            Events.assertField(event, "freeSize").atLeast(-1L); // we still get on Linux -1 in container envs
+            Events.assertField(event, "freeSize").atMost(totalSize);
         }
     }
 }