RFR: 8324995: Shenandoah: Skip to full gc for humongous allocation failures [v3]

[Kelvin Nilsen]

On Wed, 31 Jan 2024 21:50:06 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> Shenandoah degenerated cycles do not compact regions. When a humongous allocation fails, it is likely due to fragmentation which is better addressed by a full gc.
>
> William Kemper has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix typo in comment

Thanks Ramki.  I agree with your "rewording" of "what I am saying".

If anything, the changes proposed in https://github.com/openjdk/jdk/pull/17561 will reduce the likelihood that we experience a humongous alloc failure, and in the rare case that we do, will increase the likelihood that normal concurrent GC (with degen if necessary) will recover sufficient contiguous memory to satisfy the humongous allocation request.

I do agree that there's further room for smart adaptive behavior as you suggest.

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PR Comment: https://git.openjdk.org/jdk/pull/17638#issuecomment-1935039077