Why do we need a bunch of duplicate changes in jdk7u/hotspot ?

[Volker Simonis]

Hi David,

thank you very much for the detailed explanation and the links.
I missed that discussion (there are just too many mailing lists to
monitor) and now it's obviously too late to complain:)

But as far as I understood, Eriks mail  "Community Input on Hotspot 22
integration into 7u"
(http://mail.openjdk.java.net/pipermail/jdk7u-dev/2011-August/000161.html)
was about problems integrating hs22 into 7u.

Did these same problems also occur for hs23 as well? I assume yes and
if so your explanation would sound perfectly clear to me.

On the other hand I saw no definitive answer to Edvard's mail "
Proposal on how we should handle syncing between stabilisation forests
and always open 7u"
(http://mail.openjdk.java.net/pipermail/jdk7u-dev/2011-August/000161.html).

Does this mean that we will constantly see these kind of problems
(i.e. duplicate changesets with the same bug ID or even worse
duplicate changesets with different bug IDs) in the future?

Is there any "official" document available which explains the syncing
between stabilisation forests and 7u?

Thank you and best regards,
Volker

On Fri, Apr 27, 2012 at 12:45 PM, David Holmes <david.holmes at oracle.com> wrote:
> Hi Volker,
>
>
> On 27/04/2012 6:59 PM, Volker Simonis wrote:
>>
>> could anybody please explain why it was necessary to reintegrate a
>> whole lot of changes into hs23 of jdk7u/hotspot which have been in the
>> hotspot repository since hs22 anyway?
>
>
> This was discussed last year (with thanks to John Rose for these
> references):
>
> http://mail.openjdk.java.net/pipermail/jdk7u-dev/2011-August/000161.html
> http://mail.openjdk.java.net/pipermail/jdk7u-dev/2011-October/000582.html
> http://mail.openjdk.java.net/pipermail/jdk7u-dev/2011-November/000748.html
>
> Basically what you are seeing are fixes that went into hs22 and hs23 after
> hs23 forked. hs22 went into 7u2 which became the basis for 7u3 then 7u4.
> Then hs23 had to be integrated into 7u4 and so you end up with different
> changesets that duplicate the same actual changes.
>
> David
> -----
>
>
>> This all happened with the following bulk integrations:
>>
>> http://mail.openjdk.java.net/pipermail/jdk7u-dev/2012-April/002588.html
>> http://mail.openjdk.java.net/pipermail/jdk7u-dev/2012-April/002651.html
>>
>> and it affects (among others):
>>
>> 7059019: G1: add G1 support to the SA
>> 7092412: G1: Some roots not marked during an initial mark that gets an
>> evacuation failure
>> 7045232: G1: pool names are inconsistent with other collectors (don't
>> have 'Space')
>> 7068215: G1: Print reference processing time during remark
>> 7091032: G1: assert failure when NewRatio is used
>> 7092245: G1: Wrong format specifier in G1PrintRegionLivenessInfo header
>> output
>> 7092238: G1: Uninitialized field gc_efficiency in
>> G1PrintRegionLivenessInfo output
>> 6484982: G1: process references during evacuation pauses
>> 7075646: G1: fix inconsistencies in the monitoring data
>> 7086533: G1: assert(!_g1->is_obj_dead(obj)): We should not be
>> preserving dead objs: g1CollectedHeap.cpp:3835
>> 7097053: G1: assert(da ? referent->is_oop() :
>> referent->is_oop_or_null()) failed: referenceProcessor.cpp:1054
>> 7097048: G1: extend the G1 SA changes to print per-heap space information
>> 7092236: java/util/EnumSet/EnumSetBash.java fails
>> 7092278: "jmap -finalizerinfo" throws
>> "sun.jvm.hotspot.utilities.AssertionFailure: invalid cp index 0 137"
>> 7096366: PPC: corruption of floating-point values with DeoptimizeALot
>> 7100165: JSR 292: leftover printing code in methodHandleWalk.cpp
>>
>> Looking for each of this changes will show you that they are present
>> two times in the repository with exactly the same changesets. E.g.:
>> http://hg.openjdk.java.net/jdk7u/jdk7u4/hotspot/log?rev=7059019
>>
>> Regards,
>> Volker