RFR(XS) for PeriodicTask_lock cleanup (8072439)

[Daniel D. Daugherty]

On 2/17/15 3:22 PM, Carsten Varming wrote:
> Dear Daniel,
>
> Looks good to me.

Thanks for the fast review.


> The line: "OrderAccess::fence();  // ensure WatcherThread sees update 
> in main loop" seems unnecessary as the lock acts as a memory barrier.

Yes, I keep looking at that line from the original work on
JDK-7127792 and wonder why it's there... I'll chase that down
with the original folks...

Dan


>
> Carsten
>
> On Tue, Feb 17, 2015 at 4:44 PM, Daniel D. Daugherty 
> <daniel.daugherty at oracle.com <mailto:daniel.daugherty at oracle.com>> wrote:
>
>     Greetings,
>
>     My fix for the following bug:
>
>         JDK-8047720 Xprof hangs on Solaris
>
>     that was pushed to JDK9 last June needs to be cleaned up.
>
>     Thanks to Alex Garthwaite (agarthwaite at twitter.com
>     <mailto:agarthwaite at twitter.com>) and Carsten
>     Varming (varming at gmail.com <mailto:varming at gmail.com>) for
>     reporting the mess that I made
>     in WatcherThread::stop() and for suggesting fixes.
>
>     This code review is for a general cleanup pass on PeriodicTask_lock
>     and some of the surrounding code. This is a targeted review in that
>     I would like to hear from three groups of people:
>
>     1) The author and reviewers for:
>
>        JDK-7127792 Add the ability to change an existing PeriodicTask's
>                    execution interval
>
>        Rickard, David H, and Markus G.
>
>     2) The reviewers for:
>
>        JDK-8047720 Xprof hangs on Solaris
>
>        Markus G and Coleen
>
>     3) Alex and Carsten
>
>
>     Here's the webrev URL:
>
>     http://cr.openjdk.java.net/~dcubed/8072439-webrev/0-for_jdk9_hs_rt/ <http://cr.openjdk.java.net/%7Edcubed/8072439-webrev/0-for_jdk9_hs_rt/>
>
>     I've attached the original RFR for JDK-8047720 that explains
>     the original deadlock that was being fixed. Similar testing
>     will be done with this fix.
>
>     Dan
>
>

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