please help backporting some patches to stable release 19.11.14

[Morten Brørup]

> From: christian.ehrhardt at canonical.com
> Sent: Friday, 11 November 2022 12.48

[...]

> 459531c958  Morten Brørup    mempool: fix cache flushing algorithm
> a2833ecc5e  Morten Brørup    mempool: fix get objects from mempool with
> cache

These two patches fixes some performance issues for certain use cases. The affected use cases work without the patches, but don't get the improved performance.

However, these patches change the inner workings of the mempool cache.

And since some PMDs bypass the mempool API and interact directly with the mempool caches, there is a risk that applications do the same.

Although these patches are relevant for the performance of the affected use cases, I fear that backporting them would introduce an unwanted risk of breaking PMDs and/or applications (generally, not just for the affected use cases).

For the common good, I prefer not backporting them. Anyone feel free to speak up if you disagree.

We have a policy of not backporting performance improvements, and fixing a lack of performance could be interpreted as falling under this policy.