RFR: 8344068: Windows x86-64: Out of CodeBuffer space when generating final stubs

[Jatin Bhateja]

On Thu, 5 Dec 2024 16:29:57 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> I spent a while reading the dumps of final stubs. I can account for 10k additional for XMM stubs in final on Windows. This takes it to the edge.
>> 
>> It may well be that this is really a ZGC thing, but with ZGC on Linux we get nowhere near the limit. I think there is about 20k difference between Linux and Windows with ZGC enabled. I can't account for all of it, though.
>
> Okay, thank you for details.

FTR,
Following are the final stub section sizes with and without -XX:+UseZGC on linux and windows


Linux
 - With ZGC
    [0.928s][info][stubs] StubRoutines (final stubs)         [0x00007fb1afc320c0, 0x00007fb1afc3e550] used: 41659, free: 8661
 - Without ZGC
 -  [0.019s][info][stubs] StubRoutines (final stubs)         [0x00007f5e6fc2cc40, 0x00007f5e6fc390d0] used: 27419, free: 22901



Windows:
   - With ZGC 
   -  [0.043s][info][stubs] StubRoutines (final stubs)         [0x00000291ea5684c0, 0x00000291ea575120] used: 45870, free: 6450
   - Without ZGC
   - [0.039s][info][stubs] StubRoutines (final stubs)         [0x000002003a1e31c0, 0x000002003a1efe20] used: 30030, free: 22290


Hi @theRealAph , it will really help if you could kindly share the details to justify this increase.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/22516#discussion_r1875613334