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.
Seems to be quite stable. Some work still left to do.
Please note, that syscalls are not yet MP-safe, because
of the file and vnode subsystems.
Reviewed by: <tech-kern>, <ad>
- 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)
be inserted into ktrace records. The general change has been to replace
"struct proc *" with "struct lwp *" in various function prototypes, pass
the lwp through and use l_proc to get the process pointer when needed.
Bump the kernel rev up to 1.6V
message buffer has not yet been set up, mimicking code from the top of
the sysctl routine for retrieving the message buffer.
(2) Add a /l modifier to the trace command. This makes it print the
backtrace using printf() instead of db_printf(), which has the nice
side-effect of also putting it into the message buffer. A kernel with
ddb in it but disabled (ie, ddb.onpanic set to zero) will print a
backtrace (which ends up in the message buffer) before dumping (or
not, depending on the value of kern.dump_on_panic) and rebooting, but
if ddb is not disabled, the backtrace is not printed, and there's no
way to get it to display a backtrace such that you can retrieve it
after the dump. The backtrace printed by gdb is sometimes a little
different.
(3) Documentation for the above.
done by Artur Grabowski and Thomas Nordin for OpenBSD, which is more
efficient in several ways than the callwheel implementation that it is
replacing. It has been adapted to our pre-existing callout API, and
also provides the slightly more efficient (and much more intuitive)
API (adapted to the callout_*() naming scheme) that the OpenBSD version
provides.
Among other things, this shaves a bunch of cycles off rescheduling-in-
the-future a callout which is already scheduled, which the common case
for TCP timers (notably REXMT and KEEP).
The API has been simplified a bit, as well. The (very confusing to
a good many people) "ACTIVE" state for callouts has gone away. There
is now only "PENDING" (scheduled to fire in the future) and "EXPIRED"
(has fired, and the function called).
Kernel version bump not done; we'll ride the 1.6N bump that happened
with the malloc(9) change.
Make some variables and functions static when not used outside of a module.
Make variables in headers extern.
Delete the unused db_find_watchpoint() function.
"earliest" firing callout in a bucket. This allows us to skip
the scan up the bucket if no callouts are due in the bucket.
A cheap O(1) hint update is done at callout insertion (if new callout
is earlier than hint) and removal (is bucket empty). A thorough
refresh of the hint is done when the bucket is traversed.
This doesn't matter much on machines with small values of hz
(e.g. i386), but on systems with large values of hz (e.g. Alpha),
it has a definite positive effect.
Also, keep the callwheel stats in evcnts, so that you can view them
with "vmstat -e".
pointer indicating how to print the symbol. This allows db_printsym()
to called in places where db_printf() is not an appropriate output
function.
While straightforward, apologies in advance if I've introduced any minor
syntax errors; I was unable to test compilation this on all the affected
platforms.
timeout()/untimeout() API:
- Clients supply callout handle storage, thus eliminating problems of
resource allocation.
- Insertion and removal of callouts is constant time, important as
this facility is used quite a lot in the kernel.
The old timeout()/untimeout() API has been removed from the kernel.
overflow (always hated that).
replaced "/m" flag with:
/a == show process address info
/n == show normal process info [currently the default]
/w == show process wait/emul info
dsl