Suppress error warning in HotSpot backports

[Andrew Haley]

On 03/18/2014 05:53 PM, Volker Simonis wrote:
> On Tue, Mar 18, 2014 at 5:39 PM, Andrew Haley <aph at redhat.com> wrote:
>> On 03/18/2014 03:00 PM, Volker Simonis wrote:
>>> The warning is OK, just the wording is misleading.
>>>
>>> The '-XX:MaxPermSize' option is a VM (i.e. HotSpot option) so it only
>>> depends on the actual HS version and not on the JDK version.
>>>
>>> After Oracle decided to not follow the express model any more (i.e.
>>> downport new HS versions to old Java releases) for them "8.0" is
>>> equivalent to "HS 25".
>>>
>>> So you could change the wording to say something like "..was removed
>>> in this version of HotSpot". But if you run a HS 25 in Java 7 the
>>> warning is definitely reasonable and useful because the
>>> '-XX:MaxPermSize' option will be simply ignored (because the PermGen
>>> is gone).
>>
>> Is that ever something other than noise, though?  What use is that
>> message to a user?
> 
> The message is that the 'MaxPermSize' option became useless and the
> user may want to use -XX:MetaspaceSize and/or -XX:MaxMetaspaceSize if
> he has special requirements regarding class meta data. And/or he may
> wants to rethink his Java memory configuration.

Hmm.  That's not really what it says, though.

My thought is that tools like Netbeans, the Java build itself, etc,
are covered with -XX:MaxPermSize usages.  These are needed, and people
aren't going to want to remove them, and neither are they going to
want their screen full of warnings.  Would you?

>>> So do you plan do release a version of OpenJDK 7 with HS25?
>>
>> We sure do.  There's no way that we're back-porting AArch64 to
>> HS24.
>>
>>> I think we want to do the same for our commercial SAP JVM, although
>>> I'm pretty sure this will require some considerable tweaking. And
>>> Oracle will be probably reluctant to integrate such changes into
>>> HS25, because they don't want to downport it to Java 7 as far as I
>>> know. Not to speak about the fact that you'll have to maintain your
>>> own 7u-forest
>>
>> That's OK.  We can do that.
>>
>>> because the official one will probably never contain a HS25.
>>
>> Well, that depends.  If some evil security bug comes along that
>> requires a chunk 'o rewriting, Oracle may find the motivation.
>> But this piece of code just seems wrong to me: it's not that
>> unusual to back-port HotSpot releases.
> 
> Well, I'm just the messenger, but Oracle folks have been quite clear
> in communicating this.

OK.

> And you may have noticed, that the hsx-project
> will be dissolved
> (http://mail.openjdk.java.net/pipermail/hotspot-dev/2013-December/011973.html)
> after jdk8 has been released (which should be actually today:)

Sure, I know, but ... why does that matter?

Andrew.