RFR: 8142506: Reimplement TraceClassUnloading with Unified Logging. (original) (raw)

Max Ockner max.ockner at oracle.com
Thu Nov 12 19:05:18 UTC 2015

Thanks, Rachel.

I have addressed these concerns, rebuilt, and retested with jtreg runtime tests. New webrev: http://cr.openjdk.java.net/~mockner/classunload/

On 11/11/2015 3:40 PM, Rachel Protacio wrote:

Hi,

Looks good! I have a few mostly aesthetic comments: 1. Can you put the conditional part of the if statements in parentheses for clarity throughout? e.g. src/share/vm/code/nmethod.cpp:1322 2. src/share/vm/logging/logTag.hpp - It looks like there was an incomplete merge 3. In the test, the comment parts around line 26 are oddly indented. And if you can add a line for "@bug 8142506". Thanks, Rachel On 11/11/2015 3:23 PM, Max Ockner wrote: Hello, Please review my change.

Bug: https://bugs.openjdk.java.net/browse/JDK-8142506 Webrev: http://cr.openjdk.java.net/~mockner/classunload/ Testing: Hotspot jtreg tests with and without "-Xlog:classunload=trace" runthese tests with "-Xlog:classunload=trace" new jtreg test for classunload output. Summary: There are two parts to this fix. (1) Existing logic for TraceClassUnloading has been replaced with commands from Unified Logging. (2) Logging Alias Table. "-XX:+TraceClassUnloading" is now mapped to "-Xlog:classunload=debug" in the new logging alias table in arguments.cpp. Arguments are checked in the beginning of parseeachvminitarg and if an argument (such as -XX:+TraceClassUnloading") is found in the alias table, the optionString is substituted for the value found in the logging alias table. I had to make a few decisions along that might raise questions, so I will knock a few of them out now. Why didn't I use the existing alias table? - Existing alias table only stores the flag name (TraceClassUnloading) and is meant for substituting one "-XX:" argument for another. This does not solve our problem. Why didn't I process the logging aliases later in parseeachvminitarg, next to the rest of the "-XX:" argument processing? - The main processing for "-XX:" options happens after processing of "-Xlog" options. If we want the unified logging alias to be handled, it needs to be substituted in before "-Xlog:" is handled. Why does "-XX:+TraceClassUnloading" get aliased to "-Xlog:classunload=debug" and not "-Xlog:classunload=trace"? - logging statements that contained the develop-only flag "WizardMode" were converted to "-Xlog:classunload=trace". The logging statements that could have been previously been triggered in Product mode are all now accessed by "-Xlog:classunload=debug". (We are updating logging, but we are not updating the functionality of the old logging options. Old options such as TraceClassUnloading are being aliased so they may continue to work in exactly the way they did before.) Thanks, Max

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