RFR: 8312132: Add tracking of multiple address spaces in NMT [v105]

[Thomas Stuefe]

On Fri, 24 May 2024 07:25:01 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Lower number of pages
>
> src/hotspot/share/nmt/nmtNativeCallStackStorage.hpp line 119:
> 
>> 117:     }
>> 118:   }
>> 119: };
> 
> Possibly for follow up RFE: I would like to see number of stacks in the NMT statistic (there is this statistic subcommand to the jcmd VM.native_memory). I also would like to see those statistics in the hs-err file.
> 
> For example, if we ever decide to track larger stacks (which would make a lot of sense, 4 frames is really not much), we will see a logarithmic (?) increase in number of stacks. I would like to know those numbers. Note that I sometimes do that during investigations, and I have a RFE open somewhere to make the number of frames in stacks tunable with a VM options.

Note: mid-term we should place *all* stacks in here, not just those for tracking ZGC. And replace all physical copies of stacks with StackIndex.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18289#discussion_r1613003650