Virtio-fs Linux driver does not support multi-queue

[Peter-JanGootzen]

Problem
https://elixir.bootlin.com/linux/latest/C/ident/virtio_fs_wake_pending_and_unlock

In the virtio_fs_wake_pending_and_unlock function the queue on which the request will be put, is hardcoded to a single virtio-fs request queue.

Execution
Development is happening here: https://github.com/Peter-JanGootzen/linux

TODO:

• Select queue depending on CPU id
• Fix needing to use get_cpu (smp_processor_id seems not to be allowed in tasks, but get_cpu disables preemption)
• Set interrupt affinity
• Simple cat test (only runs cat on a single core)
• Big Ubuntu fio test (multi-core, check whether it actually goes into different queues with debugfs)
• CPU Hotplugging (see virtio-net)
• Implement round-robin queue scheduling (using atomics) in virtio-fs for comparison
• Send it in as a formal patch (not a priority, but would be good for the paper)