It looks good to me.
I remember the test fix needs a review as well.

Thanks,
Serguei



On 2/4/13 1:08 PM, Daniel D. Daugherty wrote:
Greetings,

I've updated the fix due to comments in Code Review Round 0.

Here is a summary of changes made to the various files:

src/share/vm/oops/cpCacheOop.cpp (HSX-23.6, HSX-24)
src/share/vm/oops/cpCache.cpp (HSX-25)
src/share/vm/oops/klassVtable.cpp
  - removed the new RC_TRACE_NO_CR() macro calls at Coleen's request;
    these files are outside of JVM/TI RedefineClasses proper so the
    tracing/debug style should not be dictated by JVM/TI RedefineClasses
    style that is currently in use
  - did not touch the existing RC_TRACE... macros in the file; removing
    the existing macro calls would be outside the scope of this bug

src/share/vm/oops/cpCacheOop.cpp (HSX-23.6, HSX-24)
src/share/vm/oops/cpCache.cpp (HSX-25)
- copy a comment from ConstantPoolCacheEntry::is_interesting_method_entry()
    to ConstantPoolCacheEntry::check_no_old_or_obsolete_entries()

src/share/vm/oops/klassVtable.cpp
  - Copied the new comment intended to prevent the "break" from
    re-materializing again from klassItable::adjust_method_entries()
    to klassVtable::adjust_method_entries(); yes, I'm paranoid.

In the HSX-25 version only:
src/share/vm/oops/metadata.hpp
  - revert changes

src/share/vm/oops/cpCacheOop.cpp
src/share/vm/oops/klassVtable.cpp
  - wrap uses of is_valid() in NOT_PRODUCT macro as appropriate

Here are the URLs for the updated webrevs:

http://cr.openjdk.java.net/~dcubed/7182152-webrev/1-hsx23.6/
http://cr.openjdk.java.net/~dcubed/7182152-webrev/1-hsx24/
http://cr.openjdk.java.net/~dcubed/7182152-webrev/1-hsx25/

The JPDA stack testing that I started on Friday is still running on
WinXP so I'm blocked for checking the recompile due to these changes.
I'll start a recompile on Solaris X86, but that will take some time.

Thanks, in advance, for more comments, suggestions or questions.

Dan



On 2/1/13 12:55 PM, Daniel D. Daugherty wrote:
Greetings,

I have a fix for the following JVM/TI bug:

    7182152 Instrumentation hot swap test incorrect monitor count
    http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7182152
    https://jbs.oracle.com/bugs/browse/JDK-7182152

The fix for the bug in the product code is one line:

src/share/vm/oops/klassVtable.cpp:

@@ -992,18 +1020,50 @@
           // RC_TRACE macro has an embedded ResourceMark
           RC_TRACE(0x00200000, ("itable method update: %s(%s)",
             new_method->name()->as_C_string(),
             new_method->signature()->as_C_string()));
         }
-        break;
+        // cannot 'break' here; see for-loop comment above.
       }
       ime++;
     }
   }
 }

and is applicable to JDK7u10/HSX-23.6 and JDK7u14/HSX-24. Coleen
already fixed the bug as part of the Perm Gen Removal (PGR) project
in HSX-25. Yes, we found a 1-line bug fix buried in the monster PGR
changeset. Many thanks to Coleen for her help in this bug hunt!

The rest of the code in the webrevs are:

- additional JVM/TI tracing code backported from Coleen's PGR changeset
- additional JVM/TI tracing code added by me and forward ported to HSX-25
- a new -XX:TraceRedefineClasses=16384 flag value for finding these
  elusive old or obsolete methods
- exposure of some printing code to the PRODUCT build so that the new
  tracing is available in a PRODUCT build

You might be wondering why the new tracing code is exposed in a PRODUCT
build. Well, it appears that more and more PRODUCT bits deployments are
using JVM/TI RedefineClasses() and/or RetransformClasses() at run-time
to instrument their systems. This bug (7182152) was only intermittently
reproducible in the WLS environment in which it occurred so I made the
tracing available in a PRODUCT build to assist in the hunt.

Raj from the WLS team has also verified that the HSX-23.6 version of
fix resolves the issue in his environment. Thanks Raj!

Here are the URLs for the three webrevs:

http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx23.6/
http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx24/
http://cr.openjdk.java.net/~dcubed/7182152-webrev/0-hsx25/

I have run the following test suites from the JPDA stack on the
JDK7u10/HSX-23.6 version of the fix with -XX:TraceRedefineClasses=16384
specified:

    sdk-jdi
    sdk-jdi_closed
    sdk-jli
    vm-heapdump
    vm-hprof
    vm-jdb
    vm-jdi
    vm-jdwp
    vm-jvmti
    vm-sajdi

The tested configs are:

    {Solaris-X86, WinXP}
      X {Client VM, Server VM}
      X {-Xmixed, -Xcomp}
      X {product, fastdebug}

With the 1-liner fix in place, the new tracing code does not find any
instances of this failure mode in any of the above test suites. Without
the the 1-liner fix in place, the new tracing code finds one instance
of this failure mode in the above test suites:

    test/java/lang/instrument/IsModifiableClassAgent.java

There are two new tests that will be pushed to the JDK repos using
a different bug ID (not yet filed):

    test/com/sun/jdi/RedefineAbstractClass.sh
test/java/lang/instrument/RedefineSubclassWithTwoInterfaces.sh

There will be a separate review request for the new tests.

I'm currently running the JPDA stack of tests on the JDK7u14/HSX-24
and JDK8-B75/HSX-25 versions of the fix. That testing will likely
take all weekend to complete.

Thanks, in advance, for any comments and/or suggestions.

Dan





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