Introduce a way to make pure kernal threads.
kthread_add() takes the same parameters as the old kthread_create()
plus a pointer to a process structure, and adds a kernel thread
to that process.

kpro

Introduce a way to make pure kernal threads.
kthread_add() takes the same parameters as the old kthread_create()
plus a pointer to a process structure, and adds a kernel thread
to that process.

kproc_kthread_add() takes the parameters for kthread_add,
plus a process name and a pointer to a pointer to a process instead of just
a pointer, and if the proc * is NULL, it creates the process to the
specifications required, before adding the thread to it.

All other old kthread_xxx() calls return, but act on (struct thread *)
instead of (struct proc *). One reason to change the name is so that
any old kernel modules that are lying around and expect kthread_create()
to make a process will not just accidentally link.

fix top to show kernel threads by their thread name in -SH mode
add a tdnam formatting option to ps to show thread names.

make all idle threads actual kthreads and put them into their own idled process.
make all interrupt threads kthreads and put them in an interd process
(mainly for aesthetic and accounting reasons)
rename proc 0 to be 'kernel' and it's swapper thread is now 'swapper'

man page fixes to follow.

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- Restore historical sched_yield() behavior by changing sched_relinquish()
to simply switch rather than lowering priority and switching. This allows
threads of equal priority to run but not le

- Restore historical sched_yield() behavior by changing sched_relinquish()
to simply switch rather than lowering priority and switching. This allows
threads of equal priority to run but not lesser priority.

Discussed with: davidxu
Reported by: NIIMI Satoshi <sa2c@sa2c.net>
Approved by: re

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- Redefine p_swtime and td_slptime as p_swtick and td_slptick. This
changes the units from seconds to the value of 'ticks' when swapped
in/out. ULE does not have a periodic timer that scans a

- Redefine p_swtime and td_slptime as p_swtick and td_slptick. This
changes the units from seconds to the value of 'ticks' when swapped
in/out. ULE does not have a periodic timer that scans all threads in
the system and as such maintaining a per-second counter is difficult.
- Change computations requiring the unit in seconds to subtract ticks
and divide by hz. This does make the wraparound condition hz times
more frequent but this is still in the range of several months to
years and the adverse effects are minimal.

Approved by: re

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- Move all of the PS_ flags into either p_flag or td_flags.
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
previously the sched_lock. These bugs have existed for some

- Move all of the PS_ flags into either p_flag or td_flags.
- p_sflag was mostly protected by PROC_LOCK rather than the PROC_SLOCK or
previously the sched_lock. These bugs have existed for some time.
- Allow swapout to try each thread in a process individually and then
swapin the whole process if any of these fail. This allows us to move
most scheduler related swap flags into td_flags.
- Keep ki_sflag for backwards compat but change all in source tools to
use the new and more correct location of P_INMEM.

Reported by: pho
Reviewed by: attilio, kib
Approved by: re (kensmith)

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- Remove the global definition of sched_lock in mutex.h to break
new code and third party modules which try to depend on it.
- Initialize sched_lock in sched_4bsd.c.
- Declare sched_lock in spar

- Remove the global definition of sched_lock in mutex.h to break
new code and third party modules which try to depend on it.
- Initialize sched_lock in sched_4bsd.c.
- Declare sched_lock in sparc64 pmap.c and assert that we're compiling
with SCHED_4BSD to prevent accidental crashes from running ULE. This
is the sole remaining file outside of the scheduler that uses the
global sched_lock.

Approved by: re

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- Move some common code out of sched_fork_exit() and back into fork_exit().

- Placing the 'volatile' on the right side of the * in the td_lock
declaration removes the need for __DEVOLATILE().

Pointed out by: tegge

- Better fix for previous error; use DEVOLATILE on the td_lock pointer
it can actually sometimes be something other than sched_lock even on
schedulers which rely on a global scheduler lock.

Te

- Better fix for previous error; use DEVOLATILE on the td_lock pointer
it can actually sometimes be something other than sched_lock even on
schedulers which rely on a global scheduler lock.

Tested by: kan

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- Pass &sched_lock as the third argument to cpu_switch() as this will
always be the correct lock and we don't get volatile warnings this
way.

Pointed out by: kan

Commit 1/14 of sched_lock decomposition.
- Move all scheduler locking into the schedulers utilizing a technique
similar to solaris's container locking.
- A per-process spinlock is now used to pr

Commit 1/14 of sched_lock decomposition.
- Move all scheduler locking into the schedulers utilizing a technique
similar to solaris's container locking.
- A per-process spinlock is now used to protect the queue of threads,
thread count, suspension count, p_sflags, and other process
related scheduling fields.
- The new thread lock is actually a pointer to a spinlock for the
container that the thread is currently owned by. The container may
be a turnstile, sleepqueue, or run queue.
- thread_lock() is now used to protect access to thread related scheduling
fields. thread_unlock() unlocks the lock and thread_set_lock()
implements the transition from one lock to another.
- A new "blocked_lock" is used in cases where it is not safe to hold the
actual thread's lock yet we must prevent access to the thread.
- sched_throw() and sched_fork_exit() are introduced to allow the
schedulers to fix-up locking at these points.
- Add some minor infrastructure for optionally exporting scheduler
statistics that were invaluable in solving performance problems with
this patch. Generally these statistics allow you to differentiate
between different causes of context switches.

Tested by: kris, current@
Tested on: i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)

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Use pause() rather than tsleep() on stack variables and function pointers.

Move the seting of the idle_mask bits to a place where they
can't be wrong.
Also use the IDLETD bit in the thread mask to test if its an idle thread
rather than doing a PCPU access.

- Remove setrunqueue and replace it with direct calls to sched_add().
setrunqueue() was mostly empty. The few asserts and thread state
setting were moved to the individual schedulers. sched_a

- Remove setrunqueue and replace it with direct calls to sched_add().
setrunqueue() was mostly empty. The few asserts and thread state
setting were moved to the individual schedulers. sched_add() was
chosen to displace it for naming consistency reasons.
- Remove adjustrunqueue, it was 4 lines of code that was ifdef'd to be
different on all three schedulers where it was only called in one place
each.
- Remove the long ifdef'd out remrunqueue code.
- Remove the now redundant ts_state. Inspect the thread state directly.
- Don't set TSF_* flags from kern_switch.c, we were only doing this to
support a feature in one scheduler.
- Change sched_choose() to return a thread rather than a td_sched. Also,
rely on the schedulers to return the idlethread. This simplifies the
logic in choosethread(). Aside from the run queue links kern_switch.c
mostly does not care about the contents of td_sched.

Discussed with: julian

- Move the idle thread loop into the per scheduler area. ULE wants to
do something different from the other schedulers.

Suggested by: jhb

Tested on: x86/amd64 sched_{4BSD, ULE, CORE}.

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Prefer a more traditional spelling of inhibited in comments and panic
messages.

Fix typo, p_slptime should be td_slptime.

Threading cleanup.. part 2 of several.

Make part of John Birrell's KSE patch permanent..
Specifically, remove:
Any reference of the ksegrp structure. This feature was
never fully utilised and made t

Threading cleanup.. part 2 of several.

Make part of John Birrell's KSE patch permanent..
Specifically, remove:
Any reference of the ksegrp structure. This feature was
never fully utilised and made things overly complicated.
All code in the scheduler that tried to make threaded programs
fair to unthreaded programs. Libpthread processes will already
do this to some extent and libthr processes already disable it.

Also:
Since this makes such a big change to the scheduler(s), take the opportunity
to rename some structures and elements that had to be moved anyhow.
This makes the code a lot more readable.

The ULE scheduler compiles again but I have no idea if it works.

The 4bsd scheduler still reqires a little cleaning and some functions that now do
ALMOST nothing will go away, but I thought I'd do that as a separate commit.

Tested by David Xu, and Dan Eischen using libthr and libpthread.

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whitespace fix only

Fix a copy-paste bug in NON-KSE case.

Unbreak userland priority inheriting in NO_KSE case.

Make KSE a kernel option, turned on by default in all GENERIC
kernel configs except sun4v (which doesn't process signals properly
with KSE).

Reviewed by: davidxu@

Add user priority loaning code to support priority propagation for
1:1 threading's POSIX priority mutexes, the code is no-op unless
priority-aware umtx code is committed.

o Fix grammar in the comment, indent macros. No functional changes.

o Remove rev. 1.57 leftover, not reached code.

Fix building with GCC 4.2: define data types before referring to them.

Add scheduler API sched_relinquish(), the API is used to implement
yield() and sched_yield() syscalls. Every scheduler has its own way
to relinquish cpu, the ULE and CORE schedulers have two internal

Add scheduler API sched_relinquish(), the API is used to implement
yield() and sched_yield() syscalls. Every scheduler has its own way
to relinquish cpu, the ULE and CORE schedulers have two internal run-
queues, a timesharing thread which calls yield() syscall should be
moved to inactive queue.

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