RFR(S) Contended Locking cleanup bucket (8062851)

[Daniel D. Daugherty]

On 11/5/14 8:49 AM, Claes Redestad wrote:
> 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.

Claes, thanks for reviewing!

Please see my reply to David H where I pickup your comments
(and hopefully resolve them).

Dan


>
> 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
>
>