RFR(XL): 8167108 - SMR and JavaThread Lifecycle

Gerald Thornbrugh gerald.thornbrugh at oracle.com
Wed Nov 22 20:21:43 UTC 2017


Hi Dan,

Your changes look good.

Jerry

> On Nov 21, 2017, at 5:12 PM, Daniel D. Daugherty <daniel.daugherty at oracle.com> wrote:
> 
> Greetings,
> 
> *** We are wrapping up code review on this project so it is time ***
> *** for the various code reviewers to chime in one last time. ***
> 
> In this latest round, we had three different reviewers chime in so we're
> doing delta webrevs for each of those resolutions:
> 
> David H's resolutions:
> 
> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-10.09,10.10.0-delta/
> 
>   mq comment for dholmes_CR:
>     - Fix indents, trailing spaces and various typos.
>     - Add descriptions for the '_cnt', '_max' and '_times" fields,
>       add impl notes to document the type choices.
> 
>   src/hotspot/share/runtime/globals.hpp change is white-space only so it
>   is only visible via the file's patch link.
> 
> 
> Robin W's resolutions:
> 
> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-10.10.0,10.10.1-delta/
> 
>   mq comment for robinw_CR:
>     - Fix some inefficient code, update some comments, fix some indents,
>       and add some 'const' specifiers.
> 
>   src/hotspot/share/runtime/vm_operations.hpp change is white-space only so
>   it is only visible via the file's patch link.
> 
> 
> Coleen's resolutions:
> 
> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-10.10.1,10.10.2-delta/
> 
>   mq comment for coleenp_CR:
>     - Change ThreadsList::_threads from 'mtGC' -> 'mtThread',
>     - add header comment to threadSMR.hpp file,
>     - cleanup JavaThreadIteratorWithHandle ctr,
>     - make ErrorHandling more efficient.
> 
> 
> Some folks prefer to see all of the delta webrevs together so here is
> a delta webrev relative to jdk10-09-full:
> 
> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-10.09,10.10.2-delta/
> 
>   src/hotspot/share/runtime/globals.hpp and
>   src/hotspot/share/runtime/vm_operations.hpp changes are white-space only
>   so they are only visible via the file's patch link.
> 
> 
> And, of course, some folks prefer to see everything all at once so here
> is the latest full webrev:
> 
> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-10.10-full/
> 
> 
> Dan has submitted the bits for the usual Mach5 tier[1-5] testing. The
> prelim Mach5 tier1 (JPRT equivalent) on these bits passed just fine...
> 
> The project is currently baselined on Jesper's 2017-11-17 PIT snapshot
> so there will be some catching up to do before integration...
> 
> We welcome comments, suggestions and feedback.
> 
> Dan, Erik and Robbin
> 
> 
> On 11/18/17 8:49 PM, Daniel D. Daugherty wrote:
>> Greetings,
>> 
>> Testing of the last round of changes revealed a hang in one of the new
>> TLH tests. Robbin has fixed the hang, updated the existing TLH test, and
>> added another TLH test for good measure.
>> 
>> Here is the updated full webrev:
>> 
>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-09-full/
>> 
>> Here is the updated delta webrev:
>> 
>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-09-delta/
>> 
>> Dan ran the bits thru the usual Mach5 tier[1-5] testing and there are
>> no unexpected failures.
>> 
>> We welcome comments, suggestions and feedback.
>> 
>> Dan, Erik and Robbin
>> 
>> 
>> On 11/15/17 3:32 PM, Daniel D. Daugherty wrote:
>>> Greetings,
>>> 
>>> Robbin rebased the project last night/this morning to merge with Thread
>>> Local Handshakes (TLH) and also picked up additional changesets up thru:
>>> 
>>>> Changeset: fa736014cf28
>>>> Author:    cjplummer
>>>> Date:      2017-11-14 18:08 -0800
>>>> URL:http://hg.openjdk.java.net/jdk/hs/rev/fa736014cf28
>>>> 
>>>> 8191049: Add alternate version of pns() that is callable from within hotspot source
>>>> Summary: added pns2() to debug.cpp
>>>> Reviewed-by: stuefe, gthornbr
>>> 
>>> This is the first time we've rebased the project to bits that are this
>>> fresh (< 12 hours old at rebase time). We've done this because we think
>>> we're done with this project and are in the final review-change-retest
>>> cycle(s)... In other words, we're not planning on making any more major
>>> changes for this project... :-)
>>> 
>>> *** Time for code reviewers to chime in on this thread! ***
>>> 
>>> Here is the updated full webrev:
>>> 
>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-08-full/
>>> 
>>> Here's is the delta webrev from the 2017.11.10 rebase:
>>> 
>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-08-delta/
>>> 
>>> Dan has submitted the bits for the usual Mach5 tier[1-5] testing
>>> (and the new baseline also)...
>>> 
>>> We're expecting this round to be a little noisier than usual because
>>> we did not rebase on a PIT snapshot so the new baseline has not been
>>> through Jesper's usual care-and-feeding of integration_blockers, etc.
>>> 
>>> We welcome comments, suggestions and feedback.
>>> 
>>> Dan, Erik and Robbin
>>> 
>>> 
>>> On 11/14/17 4:48 PM, Daniel D. Daugherty wrote:
>>>> Greetings,
>>>> 
>>>> I rebased the project to the 2017.11.10 jdk/hs PIT snapshot.
>>>> (Yes, we're playing chase-the-repo...)
>>>> 
>>>> Here is the updated full webrev:
>>>> 
>>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-07-full/
>>>> 
>>>> Unlike the previous rebase, there were no changes required to the
>>>> open code to get the rebased bits to build so there is no delta
>>>> webrev.
>>>> 
>>>> These bits have been run through JPRT and I've submitted the usual
>>>> Mach5 tier[1-5] test run...
>>>> 
>>>> We welcome comments, suggestions and feedback.
>>>> 
>>>> Dan, Erik and Robbin
>>>> 
>>>> 
>>>> On 11/13/17 12:30 PM, Daniel D. Daugherty wrote:
>>>>> Greetings,
>>>>> 
>>>>> I rebased the project to the 2017.10.26 jdk10/hs PIT snapshot.
>>>>> 
>>>>> Here are the updated webrevs:
>>>>> 
>>>>> Here's the mq comment for the change:
>>>>> 
>>>>>   Rebase to 2017.10.25 PIT snapshot.
>>>>> 
>>>>> Here is the full webrev:
>>>>> 
>>>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-06-full/
>>>>> 
>>>>> And here is the delta webrev:
>>>>> 
>>>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-06-delta/
>>>>> 
>>>>> I ran the above bits throught Mach5 tier[1-5] testing over the holiday
>>>>> weekend. Didn't see any issues in a quick look. Going to take a closer
>>>>> look today.
>>>>> 
>>>>> We welcome comments, suggestions and feedback.
>>>>> 
>>>>> Dan, Erik and Robbin
>>>>> 
>>>>> 
>>>>> On 11/8/17 1:05 PM, Daniel D. Daugherty wrote:
>>>>>> Greetings,
>>>>>> 
>>>>>> Resolving one of the code review comments (from both Stefan K and Coleen)
>>>>>> on jdk10-04-full required quite a few changes so it is being done as a
>>>>>> standalone patch and corresponding webrevs:
>>>>>> 
>>>>>> Here's the mq comment for the change:
>>>>>> 
>>>>>>   stefank, coleenp CR - refactor most JavaThreadIterator usage to use
>>>>>>     JavaThreadIteratorWithHandle.
>>>>>> 
>>>>>> Here is the full webrev:
>>>>>> 
>>>>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-05-full/
>>>>>> 
>>>>>> And here is the delta webrev:
>>>>>> 
>>>>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-05-delta/
>>>>>> 
>>>>>> We welcome comments, suggestions and feedback.
>>>>>> 
>>>>>> Dan, Erik and Robbin
>>>>>> 
>>>>>> 
>>>>>> On 10/9/17 3:41 PM, Daniel D. Daugherty wrote:
>>>>>>> Greetings,
>>>>>>> 
>>>>>>> We have a (eXtra Large) fix for the following bug:
>>>>>>> 
>>>>>>> 8167108 inconsistent handling of SR_lock can lead to crashes
>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8167108
>>>>>>> 
>>>>>>> This fix adds a Safe Memory Reclamation (SMR) mechanism based on
>>>>>>> Hazard Pointers to manage JavaThread lifecycle.
>>>>>>> 
>>>>>>> Here's a PDF for the internal wiki that we've been using to describe
>>>>>>> and track the work on this project:
>>>>>>> 
>>>>>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/SMR_and_JavaThread_Lifecycle-JDK10-04.pdf 
>>>>>>> 
>>>>>>> Dan has noticed that the indenting is wrong in some of the code quotes
>>>>>>> in the PDF that are not present in the internal wiki. We don't have a
>>>>>>> solution for that problem yet.
>>>>>>> 
>>>>>>> Here's the webrev for current JDK10 version of this fix:
>>>>>>> 
>>>>>>> http://cr.openjdk.java.net/~dcubed/8167108-webrev/jdk10-04-full
>>>>>>> 
>>>>>>> This fix has been run through many rounds of JPRT and Mach5 tier[2-5]
>>>>>>> testing, additional stress testing on Dan's Solaris X64 server, and
>>>>>>> additional testing on Erik and Robbin's machines.
>>>>>>> 
>>>>>>> We welcome comments, suggestions and feedback.
>>>>>>> 
>>>>>>> Daniel Daugherty
>>>>>>> Erik Osterlund
>>>>>>> Robbin Ehn
>>>>>>> 
>>>>>> 
>>>>>> 
>>>>> 
>>>>> 
>>>> 
>>>> 
>>> 
>>> 
>> 
>> 
> 



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