- to reduce cpu consumption for a long queue, maintain the sorted lists of
buffers with rbtree instead of TAILQ. i vaguely remember that the problem
pointed out by someone on a public mailing list while ago. sorry, i can't
remember who and where.
- add some #ifdef'ed out experimental code.
- bump kernel version for struct buf change.
BUFQ_CANCEL(queue, element) removes the specified element previously queued
on the queue. It returns NULL if it was not found on the queue and the
element if it was successfully removed.
Run trough tech-kern and changed name from BUFQ_REVOKE() by suggestion of
Jason Thorpe.
- rather than embedding bufq_state in driver softc,
have a pointer to the former.
- move bufq related functions from kern/subr_disk.c to kern/subr_bufq.c.
- rename method to strategy for consistency.
- move some definitions which don't need to be exposed to the rest of kernel
from sys/bufq.h to sys/bufq_impl.h.
(is it better to move it to kern/ or somewhere?)
- fix some obvious breakage in dev/qbus/ts.c. (not tested)
