RFR: 8307955: Prefer to PTRACE_GETREGSET instead of PTRACE_GETREGS in method 'ps_proc.c::process_get_lwp_regs'

[Chris Plummer]

On Thu, 11 May 2023 18:32:36 GMT, Guoxiong Li <gli at openjdk.org> wrote:

> Hi all,
> 
> This patch revises the code of `ps_proc.c::process_get_lwp_regs`
> to use `PTRACE_GETREGSET` first instead of `PTRACE_GETREGS`.
> The `PTRACE_GETREGS` is not present on all architectures as the man page states [1].
> And if we use `PTRACE_GETREGS` first, several tests will fail at the special envs,
> such as my local riscv64-linux env. Please see [the issue](https://bugs.openjdk.org/browse/JDK-8307955) for more information.
> 
> And I remove the unnecessary comments and macro,
> because the `sparc` arch related code had been removed.
> 
> Thanks for the review.
> 
> Best Regards,
> -- Guoxiong
> 
> [1] https://man7.org/linux/man-pages/man2/ptrace.2.html

Changes look good. I tested with our internal test system on all supported platforms and did not see any issues.

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Marked as reviewed by cjplummer (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13939#pullrequestreview-1427752843