RFR(S) Contended Locking cleanup bucket (8062851)

[Claes Redestad]

Hi,

On 11/05/2014 05:34 AM, Daniel D. Daugherty wrote:
> Greetings,
>
> I have a Contended Locking cleanup bucket fix ready for review.
>
> This fix was spun off from the Contended Locking fast enter bucket
> which was sent out for review late last week. This fix cleans up
> the computation of ObjectMonitor field pointers and gets rid of
> the use of literal '-2' in appropriate places. For example:
>
> -         ld_ptr(Rmark, ObjectMonitor::owner_offset_in_bytes() - 2, 
> Rscratch);
> +         ld_ptr(Rmark, OM_OFFSET_NO_MONITOR_VALUE(owner), Rscratch);
>
> The OM_OFFSET_NO_MONITOR_VALUE macro computes the offset to the
> specified field and subtracts markOopDesc:monitor_value (2).
> There's a nice comment in src/share/vm/runtime/objectMonitor.hpp.

any reason not to add it as a function in objectMonitor.hpp instead of a 
macro? How about:

   static int no_monitor_offset_in_bytes()  { return 
offset_of(ObjectMonitor, _owner) - markOopDesc::monitor_value; }

Example usage:

-         ld_ptr(Rmark, ObjectMonitor::owner_offset_in_bytes() - 2, Rscratch);
+         ld_ptr(Rmark, ObjectMonitor::no_monitor_offset_in_bytes(), Rscratch);


Seems this should be inlined regardless and looks a bit cleaner to me.

Thanks!

/Claes

>
> Thanks to David Holmes for his comments on JDK-8061553 that
> motivated this (long overdue) cleanup.
>
> This work is being tracked by the following bug ID:
>
>     JDK-8062851 cleanup ObjectMonitor offset adjustments
>     https://bugs.openjdk.java.net/browse/JDK-8062851
>
> Here is the webrev URL:
>
> http://cr.openjdk.java.net/~dcubed/8062851-webrev/0-jdk9-hs-rt/
>
> Here is the JEP link:
>
>     https://bugs.openjdk.java.net/browse/JDK-8046133
>
> Testing:
>
> - JPRT test jobs (since this is only syntax and comment cleanup)
>
> Thanks, in advance, for any comments, questions or suggestions.
>
> Dan