RFR: 8333658: NMT: Use an allocator with 4-byte pointers to save memory in NativeCallStackStorage [v16]

[Johan Sjölen]

On Thu, 13 Jun 2024 08:34:54 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Return on free if is_nil()
>
> Some general remarks, (apart from my remark about the integer wrapper), and then I wait until you say its ready for review.
> 
> 1) I would remove/not bother with the Allocators. There isn't much of a point, and small code is good code. The arena version is particularly questionable since Arenas don't really support arbitrary deallocation. I would not want anyone to use this allocator in real code.
> 
> 2) I would like to have a non-growing version. Optionally, one where I can hand in an address range, and that gets used. Could possibly be combined for simplicity (if you specify a range, its a non-growing array). Reason: I want to be able to place stuff that needs to be address-stable, and I often need to do this in pre-allocated ranges.

@tstuefe,

Is there anything left in this that you'd like to see?

@gerard-ziemski, @afshin-zafari , may I receive a second review on this?

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PR Comment: https://git.openjdk.org/jdk/pull/18979#issuecomment-2179128021