Disable workqueues for dm-crypt to improve latency

[igo95862]

Remember my old issue about dm-crypt making system unresponsive? #166

Turns out I am not the only one who found that issue: https://blog.cloudflare.com/speeding-up-linux-disk-encryption/

By disabling dm-crypt work queues it is possible to to significantly improve latency and even throughput.

Latency graph: (from cloudflare article)

Red: dm-crypt
Blue: dm-crypt but workqueues are disabled
Green: Plain disk

Since linux-zen is latency focused I think the dm-crypt workqueues should be disabled by default.

[igo95862]

I tested a little bit using instructions on Arch wiki: https://wiki.archlinux.org/title/Dm-crypt/Specialties

It does seem to fix the issue.

[damentz]

Reading over the Cloudflare article and seeing that their change got upstreamed, I think you're right here. A ZEN_INTERACTIVE tuning will make it to 5.17/master shortly.