[PATCH] config: limit lcore variable maximum size to 4k

[Morten Brørup]

> From: David Marchand [mailto:david.marchand at redhat.com]
> Sent: Friday, 8 November 2024 19.18
> 
> OVS locks all pages to avoid page faults while processing packets.
> 1M for each lcore translates to allocating 128M with default build
> options on x86.
> This resulted in OOM while running unit tests in parallel.
> 
> At the moment, the more demanding DPDK user of lcore variable is
> rte_service, with a 2112 bytes object.
> 
> Limit the lcore variable maximum size to 4k which looks more
> reasonable.

4 KB is not future proof.

Here's an example where 16 KB is cutting it close:
https://inbox.dpdk.org/dev/98CBD80474FA8B44BF855DF32C47DC35E9F7D0@smartserver.smartshare.dk/

Depends on how we are going to use it. 4 KB suffices if we only want to use it for "small" structures.

Would 64 KB work as a compromise?