review(XS) 7040485: Use transparent huge page on linux by default

[Y. S. Ramakrishna]

Looks good to me!

On 04/28/11 17:58, Igor Veresov wrote:
> Ramki,
> 
> Sure!
> 
> Webrev: http://cr.openjdk.java.net/~iveresov/7040485/webrev.01/
> 
> igor
> 
> On 4/28/11 3:28 PM, Y. S. Ramakrishna wrote:
>> Looks good to me. I guess I missed this nuance in my
>> previour review. Thanks also for fixing the return value.
>>
>> I had one comment about large_page_init(): it returns a
>> boolean value and sets the value of UseLargePages (on
>> Solaris and Linux). The caller then uses the return
>> value to set the value of UseLargePages again. Seems
>> a bit unpleasant. [Windows doesn't set the value
>> in large_page_init(); the caller uses the return
>> value to set UseLargePages.]
>>
>> What if the return value was just discarded and the
>> value of the flag always set in the method itself
>> prior to return? (You would then change the method
>> in the windows implementation, and change the callers
>> in the solaris and linux versions.]
>>
>> But of course all of that predates your current changes,
>> and is not directly related to the synopsis, so would
>> just be a small related clean-up you might want to roll into
>> your changset. Your choice.
>>
>> -- ramki
>>
>> On 04/28/11 15:06, Igor Veresov wrote:
>>> We should enable the use of transparent huge pages on Linux by
>>> default. The solution is to set the UseLargePages flag to true by
>>> default, but try only using UseHugeTLBFS by default if UseLargePages
>>> is not specified on the command line. We would try both UseSHM and
>>> UseHugeTLBFS methods if UseLargePages is explicitly set.
>>> This way we maintain compatibility and do not start eating into shared
>>> memory by default.
>>>
>>> Webrev: http://cr.openjdk.java.net/~iveresov/7040485/webrev.00/
>>>
>>>
>>> Thanks,
>>> igor
>