RFR: 8254972: Fix pretouch chunk calculations [v2]

[Kim Barrett]

On Thu, 29 Oct 2020 14:17:00 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Hi all,
>> 
>>   can I have reviews for this follow-up to JDK-8252221 where Kim noticed that the code in the pretouch task has some minor issues?
>> 
>> In particular, some code could be simplified and due to some inconsistencies, and used less than ideal number of workers. There is also a fix to avoid an overflow if you want to pretouch >= 16TB of heap with 4k pages (order of casts in calculation of ``num_workers``).
>> 
>> Testing: tier1
>> 
>> Thanks,
>>   Thomas
>
> Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:
> 
>   sjohanss review

Looks good.

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Marked as reviewed by kbarrett (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/884