Remove most of the now unused code for implementing PG_CACHED pages.

[alc]

Summary

This revision removes most of the code for implementing PG_CACHED pages. It does not remove user-space visible fields from vm_cnt or all of the references to cached pages from comments. Those changes will come later.

[kib]

vm/vm_page.c

1786

The description 'initialize' is somewhat weird for the remnants of this function. It only manages bookkeeping for the phys allocator, effectively.

[markj]

There are some callers of vm_page_alloc() that can be simplified a bit. For instance, shm_dotruncate() no longer needs to check the valid bits of the page returned by vm_page_alloc(). I believe the valid bit check in vm_page_grab() can be removed as well.

[alc]

vm/vm_page.c

1786

I'd like to propose some refactoring: Move the vm_phys_freecnt_adj() back to the callers, leaving only the KASSERT()s in this function. (This is actually an optimization for vm_page_alloc_contig().) Rename the function to vm_page_alloc_check(), and move the calls to a point after the free queue lock is released.

[alc]

Refactor (and rename) vm_page_alloc_init().

[kib]

I alike the update, and agree with it.

[alc]

In D8497#176612, @markj wrote:

There are some callers of vm_page_alloc() that can be simplified a bit. For instance, shm_dotruncate() no longer needs to check the valid bits of the page returned by vm_page_alloc(). I believe the valid bit check in vm_page_grab() can be removed as well.

Yes, and also vm_fault(). Today, I'm going to review all of the callers to vm_page_alloc() and update them where appropriate. I expect that to be the final change to this patch.

[alc]

Simplify callers to vm_page_alloc().

[alc]

Peter, could you please run this patch through your regular battery of tests?

[kib]

fs/tmpfs/tmpfs_subr.c

1375 ↗

(On Diff #22174)

Having vm_pager_get_pages() in the else block is not very useful: the previous then block ends in goto. Moving it out of else block reduces indent.

kern/uipc_shm.c

458 ↗

(On Diff #22174)

Same there.

[pho]

In D8497#176808, @alc wrote:

Peter, could you please run this patch through your regular battery of tests?

Sure.

[alc]

Style only changes to tmpfs_subr.c and uipc_shm.c.

[pho]

In D8497#176808, @alc wrote:

Peter, could you please run this patch through your regular battery of tests?

I ran all of the tests I have and found no problems.