On Sat, 9 Apr 2022 06:41:11 GMT, Thomas Stuefe <[email protected]> wrote:
>>> On Apr 9\, 2022\, at 2\:44 AM\, Thomas Stuefe \<stuefe at
>>> openjdk\.java\.net> wrote\:
>>>
>>> On Fri\, 8 Apr 2022 17\:34\:57 GMT\, Roman Kennke \<rkennke at
>>> openjdk\.org> wrote\:
>>>
>>>> Yes\, I get that\. But the fragments and fragment\-table are themselves
>>>> inner classes that take a MEMFLAGS template\. I could \(perhaps\) either
>>>> use a constexpr MEMFLAGS arg and pass this through\, or do at some point a
>>>> switch like\:
>>>>
>>>> \`\`\`
>>>> switch \(\_flags\) \{
>>>> case mtServiceability\:
>>>> \.\.\. new BitMapFragmentTable\<mtServiceability>\(\)\; break\;
>>>> case mtServiceability\:
>>>> \.\.\. new BitMapFragmentTable\<mtServiceability>\(\)\; break\;
>>>> default\: ShouldNotReachHere\(\)\;
>>>> \}
>>>> \`\`\`
>>>>
>>>> Which seems kinda\-ugly but would work \(I think\)\, and avoid making the
>>>> outer class template\-ized\.
>>>
>>> I see what you mean\. This MEMFLAGS template parameter is deeply interwoven
>>> into everything\. I\'d just live with the current solution\. It uses
>>> established pattern\, so at least nobody is surprised\.
>>>
>>> I think the basic problem is that CHeapObj itself is a template class\.
>>> Rethinking MEMFLAGS seems worthwhile for a future RFE\. As I wrote\, one
>>> approach could be to make them a property of the current thread\, and
>>> switchable and stackable via a Mark class\. That way\, everything allocated
>>> within a given range of frames would count toward a given category\. No
>>> need to decide on a fine\-granular basis\. No need for templates\. Maybe no
>>> need even to have a MEMFLAGS argument for every allocation\.
>>
>> While working on something else I ran into a similar problem and found a
>> different
>> approach that seemed to work well\. I\?m planning to explore it in the
>> context of
>> CHeapObj\, but haven\?t gotten around to it yet\. I should file an RFE in
>> case someone
>> else is interested\.
>
>> Yes, I get that. But the fragments and fragment-table are themselves inner
>> classes that take a MEMFLAGS template. I could (perhaps) either use a
>> constexpr MEMFLAGS arg and pass this through, or do at some point a switch
>> like:
>>
>> ```
>> switch (_flags) {
>> case mtServiceability:
>> ... new BitMapFragmentTable<mtServiceability>(); break;
>> case mtServiceability:
>> ... new BitMapFragmentTable<mtServiceability>(); break;
>> default: ShouldNotReachHere();
>> }
>> ```
>>
>> Which seems kinda-ugly but would work (I think), and avoid making the outer
>> class template-ized.
>
> I see what you mean. This MEMFLAGS template parameter is deeply interwoven
> into everything. I'd just live with the current solution. It uses established
> pattern, so at least nobody is surprised.
>
> I think the basic problem is that CHeapObj itself is a template class.
> Rethinking MEMFLAGS seems worthwhile for a future RFE. As I wrote, one
> approach could be to make them a property of the current thread, and
> switchable and stackable via a Mark class. That way, everything allocated
> within a given range of frames would count toward a given category. No need
> to decide on a fine-granular basis. No need for templates. Maybe no need even
> to have a MEMFLAGS argument for every allocation.
Have we reached a consensus that the current proposal is the way to go? If so,
could you please mark the latest revision as Reviewed (again), @tstuefe and
@coleenp (and whoever else feels like doing so)?
I also added some basic gtests for ObjectBitSet. Please note my remark on the
NULL test case.
-------------
PR: https://git.openjdk.java.net/jdk/pull/7964
