Widen aflags to 16 bits.

[markj]

Summary

We are now out of aflags bits, whereas the "flags" field only makes use
of five of its sixteen bits. I have no intention of adding a new aflag
in the near future, but would like to combine the aflags, queue and
act_count fields into a single atomically updated word. This will allow
vm_page_pqstate_cmpset() to become much simpler and is a step towards
eliminating the use of the page lock array in updating per-page queue
state.

[dougm]

sys/vm/vm_page.h

438 ↗

(On Diff #64413)

Perhaps this is an opportunity to renumber a bit and use 0x02 for something.

719 ↗

(On Diff #64413)

Would a typedef for these uses of uint16_t be appropriate?

[kib]

sys/vm/vm_page.h

239 ↗

(On Diff #64413)

Change the type to uint8_t since you are moving the line ?

[markj]

sys/vm/vm_page.h

438 ↗

(On Diff #64413)

I think that would be fine since I am changing the layout of struct vm_page anyway.

719 ↗

(On Diff #64413)

I think so, but in the next patch I will actually add a

typedef struct vm_page_astate {
    uint16_t flags;
    uint8_t queue;
    uint8_t act_count;
} vm_page_astate_t;

and pass that around instead, so I do not think there is much value in adding a typedef specifically for the flags.

[markj]

Address feedback.