RFR (S): 8006088: Incompatible heap size flags accepted by VM

[John Cuthbertson]

Hi Thomas,

Thanks for the resonse. Inline...

On 4/17/2013 12:23 AM, Thomas Schatzl wrote:
> Hi,
>
>    I had the same concerns about inconsistencies with -Xms and
> -XX:InitialHeapSize, but -Xms is (apparently) defined to set both
> minimum and initial heap size.
> I already raised that issue in an earlier discussion.

OK. I don't have a problem with it. It just looked 'odd'.
>
> If you have an official source that states that -Xms only sets minimum
> or initial heap size, I will gladly change this. I could not find
> anything; actually the documentation (java -X) for -Xms states only that it sets the initial heap size.
>
> The observations below result from this definition.
>
> On Mon, 2013-04-15 at 16:29 -0700, John Cuthbertson wrote:
>> Hi Thomas,
>>
>> Why do we treat:
>>
>> java -Xms8M  -XX:InitialHeapSize=4M...
>>
>> as an error while accepting:
> Because -Xms sets minimum heap size to 8M, and if you then set initial
> heap size to 4M there is a conflict in the general condition that
> minimum <= initial <= max.
>
>> java -XX:InitialHeapSize=4M -Xms8M...
>>
>> It looks inconsistent. In both cases the user has asked for an initial
>> heap size less than his requested minimum.
> As mentioned, -Xms unfortunately seems to be defined to set both initial
> and minimum heap size. So there is no conflict.

You're correct. I've looked at the contents of the Xusage.txt file for a 
couple of really ancient jdks and it says that it sets the initial size.


>> In collectorPolicy.cpp, can the code on lines 79-80 and 83-84 be
>> coalesced into a single line for each? This would make the setting of
>> Initial and Min consistent with the code that sets Max on line 87.
>>
> Done.
>
> See http://cr.openjdk.java.net/~tschatzl/8006088/webrev.7/ for the new
> webrev.
>
> In addition to this change I fixed the headers of the jprt test cases to
> avoid some issues with jtreg. Namely precompile the used classes and
> install the whitebox api class into the boot class path.

Thanks. collectorPolicy.cpp looks much cleaner.

Ship it.

JohnC