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

[Thomas Stuefe]

On Thu, 22 May 2025 13:16:06 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.

Could I please have reviews? @jerboaa maybe or @gnu-andrew ?

@mdoerr or @MBaesken : would it be possible to send this through your JDK17 CI too, in case our tests missed something? Thanks!

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PR Comment: https://git.openjdk.org/jdk17u-dev/pull/3607#issuecomment-2970084858
PR Comment: https://git.openjdk.org/jdk17u-dev/pull/3607#issuecomment-2970089215