On Fri, 12 Apr 2024 14:40:05 GMT, Sergey Nazarkin <snaza...@openjdk.org> wrote:
> An alternative for preemptively switching the W^X thread mode on macOS with > an AArch64 CPU. This implementation triggers the switch in response to the > SIGBUS signal if the *si_addr* belongs to the CodeCache area. With this > approach, it is now feasible to eliminate all WX guards and avoid potentially > costly operations. However, no significant improvement or degradation in > performance has been observed. Additionally, considering the issue with > AsyncGetCallTrace, the patched JVM has been successfully operated with > [asgct_bottom](https://github.com/parttimenerd/asgct_bottom) and > [async-profiler](https://github.com/async-profiler/async-profiler). > > Additional testing: > - [x] MacOS AArch64 server fastdebug *gtets* > - [ ] MacOS AArch64 server fastdebug *jtreg:hotspot:tier4* > - [ ] Benchmarking > > @apangin and @parttimenerd could you please check the patch on your > scenarios?? I agree that this PR effectively removes the whole idea behind JIT_MAP and thus is a bad idea security wise. Still it has some value. @snazarkin do you have numbers on how many transitions are done with your PR vs. the current state when running the same program? That would give us a lower bound on the amount of transitions needed and define a goal for future improvements in that area. ------------- PR Comment: https://git.openjdk.org/jdk/pull/18762#issuecomment-2056182560
