RFR: 8210889: Some service thread cleanups can be starved

[Kim Barrett]

> On Sep 19, 2018, at 2:02 AM, Per Liden <per.liden at oracle.com> wrote:
> 
> Nice! Looks good.

Thanks.

> /Per
> 
> On 09/19/2018 02:46 AM, Kim Barrett wrote:
>> Please review this small change to the ServiceThread.  When checking
>> for work to be done, rather than immediately doing the first kind of
>> work found, instead determine all pending work and then do all known
>> pending work.  This avoids the possibility of frequently available
>> work early in the sequence of checks from leading to starvation of
>> work associated with later checks.
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8210889
>> Webrev:
>> http://cr.openjdk.java.net/~kbarrett/8210889/open.00/
>> Testing:
>> mach5 tier1-3