vm_object: use reclaim callback to free pages

[dougm]

Summary

Instead of iterating over object->memq to free pages, use a callback in VM_RADIX_PCTRIE_RECLAIM_CALLBACK to do it.

[rlibby]

So the point here is to move us away from needing memq at all, correct? Taking this patch by itself, I am not seeing a performance benefit (different from your other recent uses of PCTRIE_RECLAIM_CALLBACK).

I'm not against this, I just want to make sure I understand.

sys/vm/vm_object.c

880

Nitpick:

I'd suggest choosing a name that more closely associates this with vm_object_terminate_pages, or at least doesn't read as very generic, because this routine can only be used from vm_object_terminate_pages, as it obviously doesn't do the normal cleanup. E.g. it reads as generic as vm_object_page_remove, but actually is specialized.

[dougm]

In D45588#1040431, @rlibby wrote:

So the point here is to move us away from needing memq at all, correct? Taking this patch by itself, I am not seeing a performance benefit (different from your other recent uses of PCTRIE_RECLAIM_CALLBACK).

I'm not against this, I just want to make sure I understand.

@alc suggested this, so I did it. Now, asked if he'd like to see memq replaced by pctrie iterators, he seems unenthusiastic.

[dougm]

Update callback function name and surrounding comments. No functional change.