RFR (S) 6909265: assert(_OnDeck != Self->_MutexEvent, "invariant") with -XX:+PrintMallocFree

[Zhengyu Gu]

Looks good to me.

Thanks,

-Zhengyu

On 02/01/2018 11:24 PM, coleen.phillimore at oracle.com wrote:
> 
> Okay, here is PrintMallocFree and PrintMalloc removed.   tier1,2 testing 
> is in progress.
> 
> I changed two things in addition to removing this tracing.
> 
> 1. Arena::operator new(nothrow) calls AllocateHeap to be consistent with 
> it's throw alternative.  I suspect it called os::malloc() from before 
> AllocateHeap had the flag AllocFailStrategy::RETURN_NULL.
> 2.  I have log tags malloc/free as tags to log_warning when we get a 
> memory stomping error and tracing MallocCatchPtr which is better than 
> tty->print alternative in our UL world.
> 
> open webrev at http://cr.openjdk.java.net/~coleenp/6909265.02/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-6909265
> 
> Thanks,
> Coleen
> 
> 
> On 2/1/18 6:04 PM, David Holmes wrote:
>> Hi Coleen,
>>
>> I have no experience using PrintMallocFree. Unless someone wants to 
>> champion its existance then I'd suggest just getting rid of it. We 
>> have/had a few flags that were presumably useful while 
>> debugging/devoloping something and which are left in "just in case" 
>> but then never get used.
>>
>> Thanks,
>> David
>>
>> On 1/02/2018 11:37 PM, coleen.phillimore at oracle.com wrote:
>>>
>>>
>>> On 1/31/18 10:36 PM, David Holmes wrote:
>>>> Hi Coleen,
>>>>
>>>> On 1/02/2018 1:01 PM, coleen.phillimore at oracle.com wrote:
>>>>> Summary: Convert to logging without thread locking
>>>>>
>>>>> There are two options (-XX:+PrintMallocFree and -XX:+PrintMalloc) 
>>>>> to print the calls and memory returned in malloc and free calls in 
>>>>> the vm. I converted the first one to Unified Logging which doesn't 
>>>>> crash getting the tty lock in the Thread destructor and removed the 
>>>>> latter.  I don't see the usefulness of this logging honestly, so if 
>>>>> the opinion is to remove this logging, I'd be happy to do so. NMT 
>>>>> seems much more useful.
>>>>
>>>> I'm not sure about this one. Arguably some interesting malloc/frees 
>>>> occur before log configuration.
>>>
>>> They also occurred before tty initialization and afterward too.
>>>>
>>>> That aside, given you always seem to do:
>>>>
>>>> log_is_enabled(Trace, malloc, free)
>>>>
>>>> which requires
>>>>
>>>> -Xlog:malloc+free=trace
>>>>
>>>> would it make more sense to define a single tag eg mallocfree or 
>>>> nativemem or ???
>>>>
>>>
>>> It's an opinion question.  I picked this to match the option and 
>>> assume one would want to see both mallocs and frees.  I like the 
>>> composition of small tags that have meaning.  Then again, I could 
>>> change it if you have an opinion about this.
>>>> Or, as you say, just drop this altogether. Is it useful for when 
>>>> debugging NMT?
>>>>
>>>
>>> I doubt it's useful for debugging NMT.  It might have been useful 
>>> once but I don't know why.  What's your opinion?
>>>
>>> thanks,
>>> Coleen
>>>
>>>> Thanks,
>>>> David
>>>>
>>>>> Tested with NMT and tier1 tests, and wrote test.
>>>>>
>>>>> open webrev at http://cr.openjdk.java.net/~coleenp/6909265.01/webrev
>>>>> bug link https://bugs.openjdk.java.net/browse/JDK-6909265
>>>>>
>>>>> Thanks,
>>>>> Coleen
>>>
>