RFR (M): 8016749: -XX:+UseISM fails an assert(obj->is_oop()) when running SPECjbb2005

[Vladimir Kozlov]

Albert,

reserve_memory_special() had assert which indicated that it is only called with UseISM.
Look on code in runtime/virtualspace.cpp - os::reserve_memory_special() is only call when 
os::can_commit_large_page_memory() return false. With your changes it always return 'true' (which is correct).
I think you can replace whole body of reserve_memory_special() with fatal("this obsolete method should not be called on 
Solaris"); or something.
The same is for release_memory_special() but, please, verify.

Thanks,
Vladimir

On 7/2/13 6:41 AM, Albert Noll wrote:
> Christian, Vladimir, thanks for your feedback.
>
> I added the removed flags to the ObsoleteFlag list.
>
> Vladimir, you are right. Removing all mpss-related code does not allow to use large pages anymore. I followed your
> suggestions and replaced 'UseMPSS' with 'UseLargePages'. I also checked if large pages work with 'pmap -xs' when the
> changes in webrev.01 (see below).
>
> Here is the new webrev:
> http://cr.openjdk.java.net/~anoll/8016749/webrev.01/ <http://cr.openjdk.java.net/%7Eanoll/8016749/webrev.01/>
>
> A jprt run with the above changes was successful.
>
> Thanks again,
> Albert
>
> On 02.07.2013 04:28, Vladimir Kozlov wrote:
>> Albert,
>>
>> I don't think it is incorrect changes. Only UseISM is deprecated. We still use MPSS for large pages:
>>
>> // UseLargePages UseMPSS UseISM
>> //     true      true     false => JVM will use MPSS for large page memory.
>> //                                 This is the default behavior.
>>
>> //     true      false    false => Unless future Solaris provides other
>> //                                 mechanism to use large page memory, this
>> //                                 combination is equivalent to -UseLargePages,
>> //                                 VM will not use large page memory
>>
>>
>> UseMPSS is true by default and most likely it will not work without it. So you should leave current functionality but
>> replace UseMPSS with UseLargePages flag checks in os_solaris.cpp.
>>
>> Also verify that large pages are used by java (pmap -xs) after your changes.
>>
>> thanks,
>> Vladimir
>>
>> On 7/1/13 8:35 AM, Albert Noll wrote:
>>> Hi,
>>>
>>> thanks for reviewing this patch:
>>>
>>> jbs: https://jbs.oracle.com/bugs/browse/JDK-8016749
>>> webrev: http://cr.openjdk.java.net/~anoll/8016749/webrev.00/
>>> <http://cr.openjdk.java.net/%7Eanoll/8016749/webrev.00/>
>>>
>>> Problem: ISM and MPSS are part of Solaris 9, and we do not support this
>>> version of Solaris anymore. Instead, we use LargePages for Solaris 10+.
>>>
>>> Solution: Remove all code that relates to ISM and MPSS (i.e., code that
>>> relates to the 'UseISM' and 'UseMPSS' flags).
>>>
>>> Testing: the following jprt run passes successfully.
>>>
>>> jprt submit -stree . -ot 'solaris.*' -emailalbert.noll at oracle.com
>>>
>>> Best,
>>> Albert
>