RFR: 8312132: Add tracking of multiple address spaces in NMT [v54]

[Johan Sjölen]

On Mon, 29 Apr 2024 16:34:05 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

>> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   assert device != nullptr in MemoryFileTracker::instance
>
> src/hotspot/share/nmt/nmtNativeCallStackStorage.hpp line 67:
> 
>> 65:   // 4096 buckets ensures that probability of collision is 50% at approximately 64
>> 66:   // different call stacks.
>> 67:   static const constexpr int nr_buckets = 4096;
> 
> Shouldn't that be a prime number optimally, ex. 4099? (ideally Marsenne prime, but there is one at 127 then next one is 8191)

Good point, let's go for 4099. I clarified the comment a bit also.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18289#discussion_r1587706249