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From "Alexei Fedotov" <alexei.fedo...@gmail.com>
Subject Re: [jira] Created: (HARMONY-4511) [drlvm][jvmti][gc] GC_gen doesn't collect tagged objects
Date Mon, 23 Jul 2007 10:46:17 GMT
Folks,

> These object references are enumerated as weak

There might be a coincidence with the message Harmony VM continues to print:
> The GC did not provide gc_add_weak_root_set_entry()

When we just got GC v4 before Salikh implemented weak roots they
counted as strong ones and were not collectable. Xiaofeng, does it
make sense?



On 7/23/07, Gregory Shimansky <gshimansky@gmail.com> wrote:
> Xiao-Feng Li wrote:
> > Eugene, what are tagged objects? are they non-reachable objects?
>
> Tags are JVMTI attributes that may be assigned to an object using
> SetTag() JVMTI function. These attributes may be used by heap profiler
> to analyze it. Tagged objects may be reachable or not, those that aren't
> reachable should be collected by GC. Take a look at JVMTI spec section
> that describes heap iteration API [2].
>
> In JVMTI code tags to objects are implemented as a pair of jlong and
> object reference. These object references are enumerated as weak (see
> file jvmti_tags.cpp) using gc_add_weak_root_set_entry() so GC should not
> have a problem removing unreachable objects.
>
> [1] http://java.sun.com/j2se/1.5.0/docs/guide/jvmti/jvmti.html#SetTag
> [2] http://java.sun.com/j2se/1.5.0/docs/guide/jvmti/jvmti.html#Heap
>
> > On 7/21/07, Eugene S. Ostrovsky (JIRA) <jira@apache.org> wrote:
> >> [drlvm][jvmti][gc] GC_gen doesn't collect tagged objects
> >> --------------------------------------------------------
> >>
> >>                  Key: HARMONY-4511
> >>                  URL: https://issues.apache.org/jira/browse/HARMONY-4511
> >>              Project: Harmony
> >>           Issue Type: Bug
> >>           Components: DRLVM
> >>          Environment: Windows x86
> >>             Reporter: Eugene S. Ostrovsky
> >>
> >>
> >> Objects tagged with SetTag() jvmti function are not collected by GC v5.
> >> I'm not sure whether the bug is in GC or in jvmti heap iteration
> >> implementaion.
> >>
> >>
> >> --
> >> This message is automatically generated by JIRA.
> >> -
> >> You can reply to this email to add a comment to the issue online.
> >>
> >>
> >
> >
>
>
> --
> Gregory
>
>


-- 
With best regards,
Alexei,
ESSD, Intel

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