tech-kern:
- Invert priority space so that zero is the lowest priority. Rearrange
number and type of priority levels into bands. Add new bands like
'kernel real time'.
- Ignore the priority level passed to tsleep. Compute priority for
sleep dynamically.
- For SCHED_4BSD, make priority adjustment per-LWP, not per-process.
from doc/BRANCHES:
idle lwp, and some changes depending on it.
1. separate context switching and thread scheduling.
(cf. gmcgarry_ctxsw)
2. implement idle lwp.
3. clean up related MD/MI interfaces.
4. make scheduler(s) modular.
- cv_wait and friends: after resuming execution, check to see if we have
been restarted as a result of cv_signal. If we have, but cannot take
the wakeup (because of eg a pending Unix signal or timeout) then try to
ensure that another LWP sees it. This is necessary because there may
be multiple waiters, and at least one should take the wakeup if possible.
Prompted by a discussion with pooka@.
- typedef struct lwp lwp_t;
- int -> bool, struct lwp -> lwp_t in a few places.
