RFR(M) : 8064669 : compiler/whitebox/AllocationCodeBlobTest.java crashes / asserts

[Albert Noll]

Hi Igor,

I took a quick look at your fix and the changes seem fine to me (not a 
reviewer).
Thanks a lot for taking care of this.

Best,
Albert

On 11/14/2014 04:03 PM, Igor Ignatyev wrote:
> http://cr.openjdk.java.net/~iignatyev/8064669/webrev.00/
> 261 lines changed: 231 ins; 22 del; 8 mod;
>
> Hi all,
>
> Please review patch:
>
> Problems:
> 0. NMethodSweeper::possibly_sweep is executed outside 
> CodeCacheSweeperThread
> 1. DummyBlob is initialized after the lock is released, so other 
> threads are able to see uninitialized blob
> 2. NMethodSweeper::sweep_code_cache can pass null to process_nmethod, 
> this also can lead to a crash. this situation can happen if safepoint 
> happens during sweeping and after safepoint another thread iterates 
> over all nmethods.
>
> Fix:
> 0. WB_ForceNMethodSweep use CodeCacheSweeperThread to execute 
> possibly_sweep
> 1. move ctor invocation to locked section
> 2. handle safepoint after processing nmethod in 
> NMethodSweeper::sweep_code_cache
>
> 3. added new test to verify that forceNMethodSweep actually work
> 4. AllocationCodeBlobTest is modified
>  - to checks that deoptimization works fine w/ dummy blobs
>  - to execute forceNMethodSweep more often to increase a chance to 
> catch such kind problems
>
> jbs:https://bugs.openjdk.java.net/browse/JDK-8064669
> testing: jprt + compiler/whitebox tests