RFR: 8153659: Create a CHeap backed LogStream class

[Bengt Rutisson]

> 11 apr. 2016 kl. 11:24 skrev Marcus Larsson <marcus.larsson at oracle.com>:
> 
> Hi Stefan,
> 
>> On 04/11/2016 11:19 AM, Stefan Karlsson wrote:
>> Hi all,
>> 
>> The last suggestion to move stringStreamWithResourceMark into ostream.hpp causes include circularities in the latest hs-rt code. I'd like to proceed with webrev.02 for now.
> 
> webrev.02 looks good to me as well.

+1 

Bengt

> 
> Thanks,
> Marcus
> 
>> 
>> Thanks,
>> StefanK
>> 
>>> On 2016-04-07 18:49, Stefan Karlsson wrote:
>>> Hi again,
>>> 
>>> I decided to fix the resourceArea.hpp problem, so that I could move the stringStreamWithResourceMark class into ostream.hpp.
>>> 
>>> http://cr.openjdk.java.net/~stefank/8153659/webrev.03.delta
>>> http://cr.openjdk.java.net/~stefank/8153659/webrev.03
>>> 
>>> The patch is applied on top of the thread.inline.hpp patch in:
>>> http://mail.openjdk.java.net/pipermail/hotspot-dev/2016-April/022511.html 
>>> 
>>> Thanks
>>> StefanK
>>> 
>>>> On 2016-04-07 13:30, Stefan Karlsson wrote:
>>>> Hi all,
>>>> 
>>>> I've updated the patch:
>>>> http://cr.openjdk.java.net/~stefank/8153659/webrev.02
>>>> 
>>>> The previous patch created the embedded ResourceMark after the stringStream instance was created. I discussed the layout of the classes with Bengt, and have decided to restructure this patch. I've changed the code so that the ResourceMark is embedded in a new stringStreamWithResourceMark class. This allows me to use the same LogStreamBase class, but different stringClass template parameters, for all three classes.
>>>> 
>>>> I've put the stringStreamWithResourceMark class in logStream.hpp instead of ostream.hpp, to prevent the include of resourceArea.hpp to propagate through the ostream.hpp header. The resourceArea.hpp file is problematic, since it includes and uses thread.inline.hpp. The alternative would be to move the implementation of resourceArea.hpp into a resource.inline.hpp file, so that header files could create ResourceMark instances, without having to include thread.inline.hpp. I'm leaving that exercise for another RFE.
>>>> 
>>>> Thanks,
>>>> StefanK
>>>> 
>>>>> On 2016-04-06 19:54, Stefan Karlsson wrote:
>>>>> Hi all,
>>>>> 
>>>>> Please review this patch to add a LogStream class that allocates its backing buffer from CHeap memory instead of Resource memory.
>>>>> 
>>>>> http://cr.openjdk.java.net/~stefank/8153659/webrev.01
>>>>> https://bugs.openjdk.java.net/browse/JDK-8153659
>>>>> 
>>>>> The main motivation for this is that we can't use Resource allocated memory during initialization, until Thread::current() has been initialized. So, a CHeap backed LogStream is desirable when we execute, for example, the following code during large pages initialization:
>>>>> 
>>>>> void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count)
>>>>> {
>>>>>  if (TracePageSizes) {
>>>>>    tty->print("%s: ", str);
>>>>>    for (int i = 0; i < count; ++i) {
>>>>>      tty->print(" " SIZE_FORMAT, page_sizes[i]);
>>>>>    }
>>>>>    tty->cr();
>>>>>  }
>>>>> }
>>>>> 
>>>>> The patch restructures the code and creates a LogStreamBase template base class, which takes the backing outputStream class as a template parameter. We then have three concrete LogStream classes:
>>>>> 
>>>>> LogStream - Buffer resource allocated with an embedded ResourceMark
>>>>> LogStreamNoResourceMark - Buffer resource allocated without an embedded ResourceMark
>>>>> LogStreamCHeap - Buffer CHeap allocated
>>>>> 
>>>>> I moved the LogStream class from the logStream.inline.hpp file to logStream.hpp, for consistency. If that's causing problems while reviewing this, I can move it in a separate patch.
>>>>> 
>>>>> Tested with JPRT with the TracePageSizes patch ( JDK-8152491) and internal VM tests.
>>>>> 
>>>>> Thanks,
>>>>> StefanK
>