RFR 8234270: [REDO] JDK-8204128 NMT might report incorrect numbers for Compiler area

[yumin qi]

Hi, Zhengyu

  The fix looks good to me.

Thanks
Yumin



On Wed, Nov 20, 2019 at 5:49 AM Zhengyu Gu <zgu at redhat.com> wrote:

> JDK-8204128 did not fix the original bug. But new assertion helped to
> catch the problem, as it consistently failed in Oracle internal tests.
>
> The root cause is that, when NMT biases a resource area to compiler, it
> did not adjust tracking data to reflect that. When the biased resource
> area is released, there is a possibility that its size is greater than
> total size recorded, and underflow a size_t counter.
>
> JDK-8204128 patch also missed a long to ssize_t parameter type change,
> that resulted new test failure on Windows, because long is 4-bytes on
> Windows.
>
> Many thanks to Leonid Mesnik, who helped to run this patch through
> Oracle's internal stress tests.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8234270
> Webrev: http://cr.openjdk.java.net/~zgu/JDK-8234270/webrev.00/index.html
>
>
> Test:
>    hotspot_nmt
>    Submit test
>    Oracle internal stress tests.
>
>
> Thanks,
>
> -Zhengyu
>
>