Hi Yasumasa, These comments may not make sense now that Per told that this way of iterating the heap doesn’t work for ZGC. But I am still giving them since I went through the changes.
http://cr.openjdk.java.net/~ysuenaga/JDK-8207843/webrev.00/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/z/ZPage.java.udiff.html + public int refcount() { + return topField.getJInt(addr); + } + I think you wanted to return "refcountField.getJInt(addr)" here. http://cr.openjdk.java.net/~ysuenaga/JDK-8207843/webrev.00/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/gc/z/ZAddressRangeMapForPageTable.java.frames.html 71 long size() { 72 return ZGlobals.ZAddressOffsetMax >>> ZGlobals.ZPageSizeMinShift; 73 } I am not clear about this unsigned right shift, how does this give the size ? Also ZGlobals.ZPageSizeMinShift can be replaced by AddressRangeShift. Thanks, Sharath -----Original Message----- From: Yasumasa Suenaga [mailto:yasue...@gmail.com] Sent: Thursday, July 26, 2018 7:22 PM To: serviceability-dev@openjdk.java.net; zgc-...@openjdk.java.net; hotspot-gc-dev Subject: ZGC: RFR: 8207843: HSDB cannot show Object Histogram when ZGC is working 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
