RFR(XS): 8024008: Nashorn V8 (Crypto) benchmark crashes with small CodeCache size

[Albert Noll]

Hi,

the current version causes a serious performance regression.
I have to figure out what's wrong.

Best,
Albert

On 10.09.2013 09:03, Albert Noll wrote:
> Hi Vladimir,
>
> thanks for looking at this. I checked all call sites of 
> 'make_not_entrant()' and 'make_zombie()'. I do not see any problems.
> The worst thing that can happen is that an nmethod for which the call 
> returns fals gets removed later than expected.
>
> I updated the comment and did some minor code refactoring.
>
> Also I think that it is worth considering to backport this change, 
> since the bug can appear any time
> the code cache fills up. If that bug appears, it is extremely hard to 
> reproduce and debug.
>
> Here is the updated webrev.
> http://cr.openjdk.java.net/~anoll/8024008/webrev.01/ 
> <http://cr.openjdk.java.net/%7Eanoll/8024008/webrev.01/>
>
> Best,
> Albert
>
>
>
> On 09.09.2013 19:47, Vladimir Kozlov wrote:
>> Several places in sources do not check returned result of 
>> make_not_entrant_or_zombie(). And they may assume that method marked 
>> as non-entrant, for example, because before we returned 'false' only 
>> when an other thread already changed the state to one we need.
>>
>> Can you check all call sites to make sure they work correctly with 
>> this change?
>>
>> Thanks,
>> Vladimir
>>
>> On 9/9/13 6:59 AM, Albert Noll wrote:
>>> Hi,
>>>
>>> thanks for reviewing this patch.
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8024008
>>> http://cr.openjdk.java.net/~anoll/8024008/webrev.00/ 
>>> <http://cr.openjdk.java.net/%7Eanoll/8024008/webrev.00/>
>>>
>>> Many thanks in advance,
>>> Albert
>>>
>>> Problem:
>>> The state of nmethods that are currently locked by the VM must not 
>>> change.
>>> Some operations such as setting ICs (e.g., 
>>> SharedRuntime::resolve_sub_helper())
>>> rely on this fact.  'nmethod::make_not_entrant_or_zombie does not 
>>> make this
>>> check.
>>>
>>> Solution:
>>> Do method state unchanged of nmethod is locked by the VM.
>>>
>>> Testing: Run Octane benchmarks on top of Nashorn with small code 
>>> cache size (16m).
>>>
>

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