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List:       openjdk-serviceability-dev
Subject:    Re: RFR(XS) 6625574: MemoryMXBean/Pending.java fails: "pending finalization = 0 but expected > 0"
From:       Mattias Tobiasson <mattias.tobiasson () oracle ! com>
Date:       2014-03-03 11:51:32
Message-ID: fe387641-d8aa-40dd-be29-7bac2774cb37 () default
[Download RAW message or body]

Staffan, could you please sponsor this fix?

Thanks,
Mattias

----- Original Message -----
From: staffan.larsen@oracle.com
To: mattias.tobiasson@oracle.com
Cc: serviceability-dev@openjdk.java.net
Sent: Friday, February 28, 2014 1:58:44 PM GMT +01:00 Amsterdam / Berlin / Bern / \
                Rome / Stockholm / Vienna
Subject: Re: RFR(XS) 6625574: MemoryMXBean/Pending.java fails: "pending finalization \
= 0 but expected > 0"

Looks good!

Thanks,
/Staffan

On 28 feb 2014, at 13:56, Mattias Tobiasson <mattias.tobiasson@oracle.com> wrote:

> Hi,
> Could you please review this fix?
> 
> The test often fails when run with command line "-Xcomp"
> 
> The test creates some objects and stores them in a local variable in the function. \
> The test expects those objects to survive until they are set to null. The problem \
> seems to be that the optimizer realizes that the objects are never used and removes \
> them before the test expects it. 
> The solution is to move the local variable out to a public static variable. Then \
> the optimizer will not remove it before expected.  
> webrev:
> http://cr.openjdk.java.net/~mtobiass/6625574/webrev.00
> 
> bug:
> https://bugs.openjdk.java.net/browse/JDK-6625574
> 
> Mattias


["6625574.patch" (text/x-patch)]

# HG changeset patch
# User mtobiass
# Date 1393591131 -3600
# Node ID 511f475aa2c8dbad0f636851fc8c2a032f1d64db
# Parent  0731952efb104b783b75a5765a91a91601903a3c
6625574: java/lang/management/MemoryMXBean/Pending.java fails: "pending finalization \
                = 0 but expected > 0"
Summary: Move local objs variable to a static public so the the optimizer will not \
remove it unexpectedly.

diff --git a/test/java/lang/management/MemoryMXBean/Pending.java \
                b/test/java/lang/management/MemoryMXBean/Pending.java
--- a/test/java/lang/management/MemoryMXBean/Pending.java
+++ b/test/java/lang/management/MemoryMXBean/Pending.java
@@ -76,6 +76,9 @@
         System.out.println("Test passed.");
     }
 
+    // Keep objs public so the optimizer will not remove them too early.
+    public static Object[] objs = null;
+
     private static void test() throws Exception {
         // Clean the memory and remove all objects that are pending
         // finalization
@@ -105,7 +108,7 @@
         System.out.println("   Afer creating objects with no ref: " + snapshot);
         printFinalizerInstanceCount();
 
-        Object[] objs = new Object[REF_COUNT];
+        objs = new Object[REF_COUNT];
         for (int i = 0; i < REF_COUNT; i++) {
             objs[i] = new MyObject();
         }



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