8156871: Possible concurrency issue with JVM_AddModuleExports

[Christian Tornqvist]

Hi Lois,

In /test/runtime/modules/ModuleStress/src/jdk.test/test/Main.java:

  73         // Repeatedly create the layer above stressing the exportation of 
  74         // package jdk.test/test to several different modules.
  75         ExecutorService pool = Executors.newFixedThreadPool(100);

I'm worried about the fixed number 100, especially for devices with a low number of cores (and potentially on Windows with 32bit address space). Could you put a limit on this based on min(100, Runtime.availableProcessors() * something (10?)) ? I don't need to see a new webrev for this.

Otherwise the test looks good, thanks for taking care of the testng issue.

Thanks,
Christian

-----Original Message-----
From: Lois Foltan [mailto:lois.foltan at oracle.com] 
Sent: Thursday, June 16, 2016 10:48 AM
To: Christian Tornqvist <christian.tornqvist at oracle.com>
Cc: 'hotspot-runtime-dev' <hotspot-runtime-dev at openjdk.java.net>
Subject: Re: 8156871: Possible concurrency issue with JVM_AddModuleExports


On 6/16/2016 9:37 AM, Christian Tornqvist wrote:
> Hi Lois,
>
> Ok, I see why @compile won't work for you. We should probably look at moving the CompilerUtils code into one of the shared testlibrary classes at some point, I don't think your test is the last that will need this functionality.
>
> As for testng, you can avoid using testng by simply changing the testExportModuleStress() method to be the main method and calling compileAll() from that.

Hi Christian,

I have removed the use of testng as you suggest and moved CompilerUtils.java up one level to the hotspot/test/runtime/modules directory so it can be used to develop other module tests until we have a chance to move it into the shared testlibrary classes.

http://cr.openjdk.java.net/~lfoltan/bug_jdk8156871.4/webrev/

I believe I have the required reviews for the functional piece of this, so just the test needs to be reviewed.

Thanks!
Lois

>
> Thanks,
> Christian
>
> -----Original Message-----
> From: Lois Foltan [mailto:lois.foltan at oracle.com]
> Sent: Wednesday, June 15, 2016 11:39 AM
> To: Christian Tornqvist <christian.tornqvist at oracle.com>
> Cc: 'hotspot-runtime-dev' <hotspot-runtime-dev at openjdk.java.net>
> Subject: Re: 8156871: Possible concurrency issue with 
> JVM_AddModuleExports
>
>
> On 6/15/2016 9:32 AM, Christian Tornqvist wrote:
>> Hi Lois,
>>
>> I briefly looked at the test code and I have some concerns. I see the 
>> CompilerUtils class, what prevents you from using @compile in jtreg?
>>
>> Also, it's a testng test, in Runtime we've decided to not use testng 
>> to write our tests, is there a reason for using testng here?
> Hi Christian,
>
> Thanks for reviewing the test.  CompilerUtils provides a very 
> convenient way prior to the test being run, to compile a module 
> declaration from an exploded build.  All that is needed is to provide 
> the module name and the directory location of the top of the exploded 
> directory that contains that module declaration to the CompilerUtils::compile method.
> And it allows for providing the directory where the module definition 
> once compiled, should be located.  As we develop more and more 
> extensive module tests, I think it would be unfortunate to have to 
> manually go through and need to specify for every java file that makes up that module declaration:
>
>       @compile src/jdk.test/module-info.java
>       @compile src/jdk.test/test/Main.java
>       @compile src/jdk.translet/module-info.java
>       @compile src/jdk.translet/translet/Main.java
>
> And these are just simple module declarations!  If there is a better 
> way to do this without the CompilerUtils functionality please let me 
> know, I would be happy to change it.  testng provided a way to run 
> CompilerUtils::compile prior to the actual test run.  There is 
> precedence for this in other areas of the hotspot/test directory.
>
> Thanks,
> Lois
>
>> Thanks,
>> Christian
>>
>> -----Original Message-----
>> From: hotspot-runtime-dev
>> [mailto:hotspot-runtime-dev-bounces at openjdk.java.net] On Behalf Of 
>> Lois Foltan
>> Sent: Friday, June 10, 2016 10:25 AM
>> To: hotspot-runtime-dev <hotspot-runtime-dev at openjdk.java.net>
>> Subject: RFR: 8156871: Possible concurrency issue with 
>> JVM_AddModuleExports
>>
>> Hello,
>>
>> Please review the work to finalize a concurrency issue when setting 
>> the exported state of a PackageEntry.  The work completed in bug
>> https://bugs.openjdk.java.net/browse/JDK-8152404 actually had the 
>> side effect of fixing this bug as well.  Prior to JDK-8152404, each 
>> PackageEntry determined its exported state via two flags, one of 
>> which was a general _is_exported flag followed by a another more 
>> specific state of exportability flag that determined if the package 
>> was exported qualifiedly or not to a given module.  Checking these 
>> two flags, as the
>> PackageEntry::is_* methods used to do without the Module_lock, was 
>> problematic and yielded a situation where a call to add a module to a 
>> PackageEntry's qualified exported entry list failed because it was 
>> determined that the package was unqualifiedly exported when it really 
>> was not.
>>
>> To complete this fix, I have removed the is_unqual_exported call 
>> prior to setting a PackageEntry's exported list.  The method 
>> PackageEntry::set_exported determines what the current package export 
>> state is and acts correctly.  Also, the test case has been added in 
>> this webrev since it is a good stress test case for JVM module support.
>>
>> Passes JPRT, java/lang, java/util RBT hotspot nightly.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8156871
>> Open webrev:
>> http://cr.openjdk.java.net/~lfoltan/bug_jdk8156871/webrev/
>>
>> Thanks,
>> Lois
>>
>