linuxkpi: Use pageproc instead of vmproc

[bwidawsk]

Summary

According to markj@:
pageproc contains the page daemon and laundry threads, which are
responsible for managing the LRU page queues and writing back dirty
pages. vmproc's main task is to swap out kernel stacks when the system
is under memory pressure, and swap them back in when necessary. It's a
somewhat legacy component of the system and isn't required. You can
build a kernel without it by specifying "options NO_SWAPPING" (which is
a somewhat misleading name), in which vm_swapout_dummy.c is compiled
instead of vm_swapout.c.

Based on this, we want pageproc to emulate kswapd, not vmproc.

Test Plan

N/A

[markj]

This looks ok to me. In general I'd suggest considering having the definition in a .c file so that we're not forced to pollute the namespace with FreeBSD definitions. It's probably not going to be an issue here, but it's something that does come up from time to time.

sys/compat/linuxkpi/common/include/linux/swap.h

49 ↗

(On Diff #50651)

style(9) puts parens around return values.