[jdk17u-dev] RFR: 8351500: G1: NUMA migrations cause crashes in region allocation

[Goetz Lindenmaier]

On Wed, 9 Jul 2025 08:36:50 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> This is not a clean backport. The effected G1Allocator and G1Collector methods have changed since JDK17.
>> 
>> So this backports reimplements the patch in a minimally invasive way while retaining as much similarity as possible with the original patch.
>> 
>> The gist of the patch is clear: instead of finding out the NUMA node index at every instance of G1Allocator::allocate_xxx, and then be subject to NUMA node migrations, we fix the NUMA node index once and use that one.
>> 
>> I tested this patch with my "FakeNUMA" addition (I plan to upstream that one at some point). This FakeNUMA mode mimics a lot of NUMA node migrations. I can verify that without this patch the JVM crashes quickly, with the patch it does not crash.
>
> Fix withdrawn after discussion with Severin

Hi, at tstuefe,  I'll remove the fix labels.  Could you please also mention in your fix-request comment that you withdrew it and why?  For the next one who might try backporting this?

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PR Comment: https://git.openjdk.org/jdk17u-dev/pull/3607#issuecomment-3057283230