Hi,
On 08/08/2018 10:00 AM, Yasumasa Suenaga wrote:
Hi Per,
Will class unloading be occurred after relocation?
No, before relocation.
/Per
If so, I think we can use this approach.
I read the slide [1], it says any garbage does not exist in ZPage after
relocation.
Thanks,
Yasumasa
[1]
https://www.jfokus.se/jfokus18/preso/ZGC--Low-Latency-GC-for-OpenJDK.pdf
On 2018/08/08 0:28, Per Liden wrote:
Hi,
On 08/07/2018 03:02 PM, Yasumasa Suenaga wrote:
Hi Per,
Currently, class unloading seems not to be implemented.
So do not worry about it?
Support for class unloading is coming, so this assumption would not
hold for very long.
cheers,
Per
http://hg.openjdk.java.net/jdk/jdk/file/10ef3d870cb7/src/hotspot/share/gc/z/zArguments.cpp#l86
Thanks,
Yasumasa
On 2018/08/07 21:32, Per Liden wrote:
Hi Yasumasa,
I'm afraid this approach of iterating over objects doesn't work. In
ZGC, you can't walk over ZPages since some objects in there might be
unreachable and hence might have an invalid/dead class pointer,
which in turn means you can't tell the size of the object. When
iterating over the heap you must start from the roots and only visit
live objects. This becomes very complicated to do in the SA, which
is why it hasn't been implemented.
cheers,
Per
On 07/26/2018 03:52 PM, Yasumasa Suenaga wrote:
CC'ing to hotspot-gc-dev
On 2018/07/26 21:30, Yasumasa Suenaga wrote:
PING: Could you review it?
webrev:
http://cr.openjdk.java.net/~ysuenaga/JDK-8207843/webrev.00/
Yasumasa
On 2018/07/19 23:03, Yasumasa Suenaga wrote:
Hi all,
Please review this webrev.
JBS: https://bugs.openjdk.java.net/browse/JDK-8207843
webrev:
http://cr.openjdk.java.net/~ysuenaga/JDK-8207843/webrev.00/
I encountered AssertionFailure when I attached HSDB to the
process which is working with ZGC as below:
sun.jvm.hotspot.utilities.AssertionFailure: Unexpected
CollectedHeap type: sun.jvm.hotspot.gc.z.ZCollectedHeap
at
jdk.hotspot.agent/sun.jvm.hotspot.utilities.Assert.that(Assert.java:32)
at
jdk.hotspot.agent/sun.jvm.hotspot.oops.ObjectHeap.collectLiveRegions(ObjectHeap.java:448)
at
jdk.hotspot.agent/sun.jvm.hotspot.oops.ObjectHeap.iterate(ObjectHeap.java:173)
at
jdk.hotspot.agent/sun.jvm.hotspot.HSDB$VisitHeap.run(HSDB.java:1741)
at
jdk.hotspot.agent/sun.jvm.hotspot.utilities.WorkerThread$MainLoop.run(WorkerThread.java:70)
at java.base/java.lang.Thread.run(Thread.java:832)
ObjectHeap#collectLiveRegions() branches by instance type of
CollectedHeap. However it does not support ZCollectedHeap.
So I add ZCollectedHeap to it and add some methods to iterate
ZPageTable.
Thanks,
Yasumasa
