[prev in list] [next in list] [prev in thread] [next in thread] 

List:       openjdk-hotspot-runtime-dev
Subject:    Re: RFR (S): 8191894: Refactor weak references in JvmtiTagHashmap to use the Access API
From:       coleen.phillimore () oracle ! com
Date:       2017-11-28 20:20:59
Message-ID: 59c3d40e-6493-7ca2-3ff3-9cc15fa461c3 () oracle ! com
[Download RAW message or body]



On 11/28/17 7:37 AM, Erik Österlund wrote:
> Hi Coleen,
> 
> That's it, yes. Hope I answered the question.

Yes, thanks.
Coleen

> 
> Thanks,
> /Erik
> 
> On 2017-11-27 19:28, coleen.phillimore@oracle.com wrote:
> > 
> > 
> > On 11/27/17 1:21 PM, coleen.phillimore@oracle.com wrote:
> > > http://cr.openjdk.java.net/~eosterlund/8191894/webrev.00/src/hotspot/share/prims/jvmtiTagMap.cpp.udiff.html \
> > >  
> > > 
> > > + return RootAccess<ON_PHANTOM_OOP_REF | 
> > > AS_NO_KEEPALIVE>::oop_load(object_addr());
> > > 
> > 
> > Sorry I have my Access API dimensions mixed up.   RootAccess is 
> > IN_ROOT not ON_ROOT (and not concurrent).
> > 
> > Coleen
> > > 
> > > Why is this not access ON_ROOT{_CONCURRENT} ?   The thing holding the 
> > > object that you are peeking at is not in the Java Heap?
> > > 
> > > thanks,
> > > Coleen
> > > 
> > > On 11/27/17 6:28 AM, Erik Österlund wrote:
> > > > Hi,
> > > > 
> > > > The JVMTI tag hashmap has weak oop references that are handled 
> > > > using raw oop accesses and a G1-specific SATB enqueue call when 
> > > > leaking out objects from the tag map, requiring them to be marked 
> > > > as live by G1.
> > > > 
> > > > This should now be refactored to use the Access API to annotate 
> > > > that these are ON_PHANTOM_OOP_REF, and refactor the raw oop loads 
> > > > to use ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE.
> > > > 
> > > > Webrev:
> > > > http://cr.openjdk.java.net/~eosterlund/8191894/webrev.00/
> > > > 
> > > > Bug:
> > > > https://bugs.openjdk.java.net/browse/JDK-8191894
> > > > 
> > > > Thanks,
> > > > /Erik
> > > 
> > 
> 


[prev in list] [next in list] [prev in thread] [next in thread]