RFR: 8337563: NMT: rename MEMFLAGS to MemTag [v7]

[Gerard Ziemski]

On Tue, 10 Sep 2024 20:53:46 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

>> Please review this cleanup, where we rename `MEMFLAGS` to `MemTag`.
>> 
>> `MEMFLAGS` implies that we can use more than one at the same time, but those are exclusive values, so `MemTag` is a more suitable name.
>> 
>> This fix also includes a cleanup of all the related function/template parameter names and local variable names.
>> 
>> Testing is pending...
>> 
>> Note: there is more history in old closed PRs [https://github.com/openjdk/jdk/pull/20497](https://github.com/openjdk/jdk/pull/20497) and [https://github.com/openjdk/jdk/pull/20472](https://github.com/openjdk/jdk/pull/20472)
>
> Gerard Ziemski has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Coleen's feedback

Are we sure we want `mt` for non-type parameter name in templates? We have these existing patterns already in our code:


src/hotspot/share/utilities/growableArray.hpp:803:template <typename E, MemTag MT>
src/hotspot/share/utilities/stack.hpp:54:template <class E, MemTag MT> class StackIterator;
src/hotspot/share/utilities/concurrentHashTable.inline.hpp:78:template <typename CONFIG, MemTag MT>
src/hotspot/share/utilities/chunkedList.hpp:31:template <class T, MemTag MT> class ChunkedList : public CHeapObj<MT> 
src/hotspot/share/gc/g1/g1BatchedTask.hpp:32:template <typename E, MemTag MT>
src/hotspot/share/gc/shared/taskqueue.hpp:119:template <unsigned int N, MemTag MT>
src/hotspot/share/gc/shared/taskqueue.hpp:327:template <class E, MemTag MT, unsigned int N = TASKQUEUE_SIZE>
src/hotspot/share/gc/shenandoah/shenandoahTaskqueue.hpp:40:template<class E, MemTag MT, unsigned int N = TASKQUEUE_SIZE>
src/hotspot/share/nmt/arrayWithFreeList.hpp:34:template<typename E, MemTag MT>


With mt they would look like:


src/hotspot/share/utilities/growableArray.hpp:803:template <typename E, MemTag mt>
src/hotspot/share/utilities/stack.hpp:54:template <class E, MemTag mt> class StackIterator;
src/hotspot/share/utilities/concurrentHashTable.inline.hpp:78:template <typename CONFIG, MemTag mt>
src/hotspot/share/utilities/chunkedList.hpp:31:template <class T, MemTag mt> class ChunkedList : public CHeapObj<mt> 
src/hotspot/share/gc/g1/g1BatchedTask.hpp:32:template <typename E, MemTag mt>
src/hotspot/share/gc/shared/taskqueue.hpp:119:template <unsigned int N, MemTag mt>
src/hotspot/share/gc/shared/taskqueue.hpp:327:template <class E, MemTag mt, unsigned int N = TASKQUEUE_SIZE>
src/hotspot/share/gc/shenandoah/shenandoahTaskqueue.hpp:40:template<class E, MemTag mt, unsigned int N = TASKQUEUE_SIZE>
src/hotspot/share/nmt/arrayWithFreeList.hpp:34:template<typename E, MemTag mt>


So `MT` or `mt` for non-type parameter name in templates, or should I punt on this particular change and leave it for a followup?

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PR Comment: https://git.openjdk.org/jdk/pull/20872#issuecomment-2343769766