Deadlock between physmem_lock and pv_list_lock about mimiker HOT 3 CLOSED

Here's another instance of this dead-lock: https://github.com/cahirwpz/mimiker/pull/974/checks?check_run_id=1861738645

from mimiker.

First code inspection reveals that there's responsibility overload in pm_free_from_seg.

In the same module we use pmap in vm_boot_alloc and that's seems ok. However pm_free_from_seg tries to do too much. We would like it to be a simple and well-defined tool, which we use to perform more complex actions. However it breaks abstraction by calling pmap_page_remove and that's the source of our problem.

EDIT: In other words – we would like pm_free_from_seg to be leaf-call.

from mimiker.

We have about a dozen of uses of vm_page_free. Each one of them should be called only if vm_page_t reference counter (which we do not maintain) drops to zero.

Most likely pmap_page_remove should be renamed to pmap_remove_all as in FreeBSD. We should add plain pmap_remove and maybe pmap_remove_pages. Perhaps introduction of these functions will help us to remove call to pmap_page_remove from pm_free_from_seg.

from mimiker.