On Mon, 22 Dec 2025 19:01:54 GMT, Chris Plummer <[email protected]> wrote:
>> Another solution is make some sleep after call `unloadClass()`
>>
>>
>> diff --git
>> a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001.java
>>
>> b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001.java
>> index 13058ec7864..15120d3cad6 100644
>> ---
>> a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001.java
>> +++
>> b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/CompiledMethodUnload/compmethunload001.java
>> @@ -47,7 +47,7 @@ public class compmethunload001 {
>> private final static String CLS_TO_BE_UNLOADED =
>> "nsk.jvmti.CompiledMethodUnload.compmethunload001u";
>>
>> - private final static int MAX_ITERATIONS = 50;
>> + private final static int MAX_ITERATIONS = 5;
>>
>> static {
>> try {
>> @@ -95,6 +95,7 @@ public static void callHotClass(String location) throws
>> Exception {
>>
>> boolean clsUnloaded = clsUnLoader.unloadClass();
>> clsUnLoader = null;
>> + Thread.sleep(5000);
>> System.gc();
>> }
>
> It seems this is somewhat poorly written test and is also somewhat imprecise
> and presumpive. I'm guessing the unload is delayed a bit because it happens
> async, and you can't really guess how long it is going to take for the unload
> to happen. The loop and the System.gc() calls are just passing time until the
> unload happens. The System.gc() calls should not be needed since the
> ClassUnloader.unloadClass() call should have been sufficient. I would suggest
> removing both System.gc() calls and just have a loop that does short sleeps
> until the unload happens. Maybe limit the loop to no more than 10 seconds. A
> more elegant approach would be to wait on a monitor for no more than 10
> seconds, and have the native code notify the monitor when the unload happens.
The code "wait on a monitor and notify from JNI" seems too complex for me. So I
just limit the loop to no more than 10 seconds.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/28891#discussion_r2641853242
