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

[Igor Veresov]

Thanks, Ramki!

On 4/28/11 6:45 PM, Y. S. Ramakrishna wrote:
> 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
>>