Re: [RFA] Suspend counting for JDWP

[Bryce McKinlay <mckinlay at redhat dot com>]

Keith Seitz wrote:
> So now all the pieces are in place to implement _Jv_ThreadDebug*. The 
> attached patch does this for POSIX threads only. Win32 and whatever 
> threading system supported by gij will need implementing eventually.
>
> Keith
>
> ChangeLog
> 2006-06-26  Keith Seitz  <keiths@redhat.com>
>
>         * include/posix-threads.h (_Jv_Thread_t): Add mutex and
>         count for JDWP suspend counting.
>         * posix-threads.cc (_Jv_ThreadInitData): Initialize suspend
>         couont mutex and initial count.
>         (_Jv_ThreadDestroyData): Destroy suspend count mutex.
>         (_Jv_ThreadDebugResume): Implement.
>         (_Jv_ThreadDebugSuspendCount): Likewise.
>         (_Jv_ThreadDebugSuspend): Likewise.


I wonder if it is worthwhile to maintain a suspend_count_mutex for every 
thread, particularly when it will only be needed during debugging 
sessions. Perhaps a single, global mutex is sufficient?

Are we likely to need to associate other JVMTI/JDWP debugging data with 
a thread? If so then it might be wise to put these in a 
_Jv_ThreadDebugInfo (or some such) struct which would be initialized 
only when JDWP is in use.

If we had that, these suspend functions could be made "generic" - put in 
a jvmti.cc or some such, and we'd only need a _Jv_GetThreadDebugInfo in 
posix-threads.h/win32-threads.h.

Does this sound reasonable?

Bryce