Commit Graph

215 Commits

Author SHA1 Message Date
David Xu
6ce75196ce Adjust code for userland preemptive. Userland can set a quantum in
kse_mailbox to schedule an upcall, this is useful for userland timeout
routine, for example pthread_cond_timedwait().

Also extract upcall scheduling code from kse_reassign and create
a new function called thread_switchout to include these code.

Reviewed by: julain
2003-03-19 05:49:38 +00:00
John Baldwin
263067951a Replace calls to WITNESS_SLEEP() and witness_list() with equivalent calls
to WITNESS_WARN().
2003-03-04 21:03:05 +00:00
Hartmut Brandt
b89bc9e62b When a process has been waiting on a condition variable or mutex the
td_wmesg field in the thread structure points to the description string of
the condition variable or mutex. If the condvar or the mutex had been
initialized from a loadable module that was unloaded in the meantime,
td_wmesg may now point to invalid memory. Retrieving the process table now
may panic the kernel (or access junk). Setting the td_wmesg field to NULL
after unblocking on the condvar/mutex prevents this panic.

PR:		kern/47408
Approved by:	jake (mentor)
2003-02-27 08:43:27 +00:00
Julian Elischer
ac2e415327 Change the process flags P_KSES to be P_THREADED.
This is just a cosmetic change but I've been meaning to do it for about a year.
2003-02-27 02:05:19 +00:00
Julian Elischer
4a338afd7a Move a bunch of flags from the KSE to the thread.
I was in two minds as to where to put them in the first case..
I should have listenned to the other mind.

Submitted by:	 parts by davidxu@
Reviewed by:	jeff@ mini@
2003-02-17 09:55:10 +00:00
Alfred Perlstein
aae87a3681 Print a backtrace in case we tsleep from inside of DDB. 2003-02-14 12:44:07 +00:00
Julian Elischer
93a7aa79d6 Add code to ddb to allow backtracing an arbitrary thread.
(show thread {address})

Remove the IDLE kse state and replace it with a change in
the way threads sahre KSEs. Every KSE now has a thread, which is
considered its "owner" however a KSE may also be lent to other
threads in the same group to allow completion of in-kernel work.
n this case the owner remains the same and the KSE will revert to the
owner when the other work has been completed.

All creations of upcalls etc. is now done from
kse_reassign() which in turn is called from mi_switch or
thread_exit(). This means that special code can be removed from
msleep() and cv_wait().

kse_release() does not leave a KSE with no thread any more but
converts the existing thread into teh KSE's owner, and sets it up
for doing an upcall. It is just inhibitted from being scheduled until
there is some reason to do an upcall.

Remove all trace of the kse_idle queue since it is no-longer needed.
"Idle" KSEs are now on the loanable queue.
2002-12-28 01:23:07 +00:00
Julian Elischer
696058c3c5 Unbreak the KSE code. Keep track of zobie threads using the Per-CPU storage
during the context switch. Rearrange thread cleanups
to avoid problems with Giant. Clean threads when freed or
when recycled.

Approved by:	re (jhb)
2002-12-10 02:33:45 +00:00
Jeff Roberson
148302c9c9 - Move FSCALE back to kern_sync. This is not scheduler specific.
- Create a new callout for lbolt and move it out of schedcpu().  This is not
   scheduler specific either.

Approved by:	re
2002-11-21 08:57:08 +00:00
David Xu
34e80e027d Add an actual implementation of kse_thr_interrupt() 2002-10-30 02:28:41 +00:00
Julian Elischer
9d10277721 More work on the interaction between suspending and sleeping threads.
Also clean up some code used with 'single-threading'.

Reviewed by:	davidxu
2002-10-25 07:11:12 +00:00
Jeff Roberson
b43179fbe8 - Create a new scheduler api that is defined in sys/sched.h
- Begin moving scheduler specific functionality into sched_4bsd.c
 - Replace direct manipulation of scheduler data with hooks provided by the
   new api.
 - Remove KSE specific state modifications and single runq assumptions from
   kern_switch.c

Reviewed by:	-arch
2002-10-12 05:32:24 +00:00
John Baldwin
5715307f74 - Move p_cpulimit to struct proc from struct plimit and protect it with
sched_lock.  This means that we no longer access p_limit in mi_switch()
  and the p_limit pointer can be protected by the proc lock.
- Remove PRS_ZOMBIE check from CPU limit test in mi_switch().  PRS_ZOMBIE
  processes don't call mi_switch(), and even if they did there is no longer
  the danger of p_limit being NULL (which is what the original zombie check
  was added for).
- When we bump the current processes soft CPU limit in ast(), just bump the
  private p_cpulimit instead of the shared rlimit.  This fixes an XXX for
  some value of fix.  There is still a (probably benign) bug in that this
  code doesn't check that the new soft limit exceeds the hard limit.

Inspired by:	bde (2)
2002-10-09 17:17:24 +00:00
Julian Elischer
48bfcddd94 Round out the facilty for a 'bound' thread to loan out its KSE
in specific situations. The owner thread must be blocked, and the
borrower can not proceed back to user space with the borrowed KSE.
The borrower will return the KSE on the next context switch where
teh owner wants it back. This removes a lot of possible
race conditions and deadlocks. It is consceivable that the
borrower should inherit the priority of the owner too.
that's another discussion and would be simple to do.

Also, as part of this, the "preallocatd spare thread" is attached to the
thread doing a syscall rather than the KSE. This removes the need to lock
the scheduler when we want to access it, as it's now "at hand".

DDB now shows a lot mor info for threaded proceses though it may need
some optimisation to squeeze it all back into 80 chars again.
(possible JKH project)

Upcalls are now "bound" threads, but "KSE Lending" now means that
other completing syscalls can be completed using that KSE before the upcall
finally makes it back to the UTS. (getting threads OUT OF THE KERNEL is
one of the highest priorities in the KSE system.) The upcall when it happens
will present all the completed syscalls to the KSE for selection.
2002-10-09 02:33:36 +00:00
Juli Mallett
a723033a4d XXX Add a check for p->p_limit being NULL before dereferencing it. This is
totally bogus but will hide the occurances of access of 0xbc(NULL) which
people have run into lately.  This is not a proper fix, just a bandaid, until
the cause of this happening is tracked down and fixed.

Reviewed by:	rwatson
2002-10-03 04:09:00 +00:00
John Baldwin
551cf4e150 Rename the mutex thread and process states to use a more generic 'LOCK'
name instead.  (e.g., SLOCK instead of SMTX, TD_ON_LOCK() instead of
TD_ON_MUTEX())  Eventually a turnstile abstraction will be added that
will be shared with mutexes and other types of locks.  SLOCK/TDI_LOCK will
be used internally by the turnstile code and will not be specific to
mutexes.  Making the change now ensures that turnstiles can be dropped
in at a later date without affecting the ABI of userland applications.
2002-10-02 20:31:47 +00:00
John Baldwin
1d56414515 - Adjust comment noting that handling of CPU limit exhaustion is done in
ast().
- Actually set KEF_ASTPENDING so ast() is called.  I think this is buggy
  for a process with multiple KSE's in that PS_XCPU is not a KSE event,
  it's a process-wide event.  IMO there really should probably be two
  ASTPENDING flags, one for per-process, and one for per-KSE.

Submitted by:	bde
2002-10-01 14:10:08 +00:00
John Baldwin
dc183990ca - Add a new per-process flag PS_XCPU to indicate that at least one thread
has exceeded its CPU time limit.
- In mi_switch(), set PS_XCPU when the CPU time limit is exceeded.
- Perform actual CPU time limit exceeded work in ast() when PS_XCPU is set.

Requested by:	many
2002-09-30 21:13:54 +00:00
Julian Elischer
9eb1fdea37 Implement basic KSE loaning. This stops a hread that is blocked in BOUND mode
from stopping another thread from completing a syscall, and this allows it to
release its resources etc. Probably more related commits to follow (at least
one I know of)

Initial concept by: julian, dillon
Submitted by:	davidxu
2002-09-29 23:04:34 +00:00
Julian Elischer
71fad9fdee Completely redo thread states.
Reviewed by:	davidxu@freebsd.org
2002-09-11 08:13:56 +00:00
Julian Elischer
472be95807 Rejig the code to figure out estcpu and work out how long a KSEGRP has been
idle. What was there before was surprisingly ALMOST correct.

Peter and I fried our brains on this for a couple of hours figuring out
what this actually means in the context of multiple threads.

Reviewed by:	peter@freebsd.org
2002-08-30 00:25:49 +00:00
Peter Wemm
d13947c3b0 updatepri() works on a ksegrp (where the scheduling parameters are), so
directly give it the ksegrp instead of the thread.  The only thing it used
to use in the thread was the ksegrp.

Reviewed by:	julian
2002-08-28 23:45:15 +00:00
Julian Elischer
04774f2357 Slight cleanup of some comments/whitespace.
Make idle process state more consistant.
Add an assert on thread state.
Clean up idleproc/mi_switch() interaction.
Use a local instead of referencing curthread 7 times in a row
(I've been told curthread can be expensive on some architectures)
Remove some commented out code.
Add a little commented out code (completion coming soon)

Reviewed by:	jhb@freebsd.org
2002-08-01 18:45:10 +00:00
Seigo Tanimura
133267776c In endtsleep() and cv_timedwait_end(), a thread marked TDF_TIMEOUT may
be swapped out.  Do not put such the thread directly back to the run
queue.

Spotted by:	David Xu <davidx@viasoft.com.cn>

While I am here, s/PS_TIMEOUT/TDF_TIMEOUT/.
2002-07-30 10:12:11 +00:00
Seigo Tanimura
9eb881f804 - Optimize wakeup() and its friends; if a thread waken up is being
swapped in, we do not have to ask for the scheduler thread to do
  that.

- Assert that a process is not swapped out in runq functions and
  swapout().

- Introduce thread_safetoswapout() for readability.

- In swapout_procs(), perform a test that may block (check of a
  thread working on its vm map) first.  This lets us call swapout()
  with the sched_lock held, providing a better atomicity.
2002-07-30 06:54:05 +00:00
Julian Elischer
1d7b9ed2e6 Create a new thread state to describe threads that would be ready to run
except for the fact tha they are presently swapped out. Also add a process
flag to indicate that the process has started the struggle to swap
back in. This will be  needed for the case where multiple threads
start the swapin action top a collision. Also add code to stop
a process fropm being swapped out if one of the threads in this
process is actually off running on another CPU.. that might hurt...

Submitted by:	Seigo Tanimura <tanimura@r.dl.itc.u-tokyo.ac.jp>
2002-07-29 18:33:32 +00:00
Julian Elischer
294e6308bf slight stylisations to take into account recent code changes. 2002-07-24 23:59:15 +00:00
Julian Elischer
2d014fd7f8 Fix a reversed test.
Fix some style nits.
Fix a KASSERT message.
Add/fix some comments.

Submitted by:	bde@freebsd.org
2002-07-17 19:20:48 +00:00
John Baldwin
627ed43ba7 Add a KASSERT() to assert that td_critnest is == 1 when mi_switch() is
called.
2002-07-17 02:46:13 +00:00
Andrew Gallatin
fe79953325 Allow alphas to do crashdumps: Refuse to run anything in choosethread()
after a panic which is not an interrupt thread, or the thread which
caused the panic.  Also, remove panicstr checks from msleep() and from
cv_wait() in order to allow threads to go to sleep and yeild the cpu
to the panicing thread, or to an interrupt thread which might
be doing the crashdump.

Reviewed by: jhb  (and it was mostly his idea too)
2002-07-17 02:23:44 +00:00
Julian Elischer
c3b98db091 Thinking about it I came to the conclusion that the KSE states were incorrectly
formulated.  The correct states should be:
IDLE:  On the idle KSE list for that KSEG
RUNQ:  Linked onto the system run queue.
THREAD: Attached to a thread and slaved to whatever state the thread is in.

This means that most places where we were adjusting kse state can go away
as it is just moving around because the thread is..
The only places we need to adjust the KSE state is in transition to and from
the idle and run queues.

Reviewed by:	jhb@freebsd.org
2002-07-14 03:43:33 +00:00
Julian Elischer
ac8bcbb700 oops, state cannot be two different values at once..
use || instead of &&
2002-07-14 01:36:48 +00:00
Matthew Dillon
fbcf77c2ea Re-enable the idle page-zeroing code. Remove all IPIs from the idle
page-zeroing code as well as from the general page-zeroing code and use a
lazy tlb page invalidation scheme based on a callback made at the end
of mi_switch.

A number of people came up with this idea at the same time so credit
belongs to Peter, John, and Jake as well.

Two-way SMP buildworld -j 5 tests (second run, after stabilization)
    2282.76 real  2515.17 user  704.22 sys	before peter's IPI commit
    2266.69 real  2467.50 user  633.77 sys	after peter's commit
    2232.80 real  2468.99 user  615.89 sys	after this commit

Reviewed by:	peter, jhb
Approved by:	peter
2002-07-12 20:17:06 +00:00
Julian Elischer
fe0f1bf4b1 make this repect ps_sigintr if there is a pre-existing signal
or suspension request.

Submitted by:	David Xu
2002-07-06 08:47:24 +00:00
Julian Elischer
55fb7ca894 Fix at least one of the things wrong with signals
^Z should work a lot better now.

Submitted by:	peter@freebsd.org
2002-07-06 02:45:11 +00:00
Julian Elischer
aa0fa33464 Try clean up some of the mess that resulted from layers and layers
of p4 merges from -current as things started getting different.

Corroborated by: Similar patches just mailed by BDE.
2002-07-03 09:15:20 +00:00
Julian Elischer
8b768fc82b When going back to SLEEP state, make sure our
State is correctly marked so.
2002-07-02 05:40:51 +00:00
Julian Elischer
e602ba25fd Part 1 of KSE-III
The ability to schedule multiple threads per process
(one one cpu) by making ALL system calls optionally asynchronous.
to come: ia64 and power-pc patches, patches for gdb, test program (in tools)

Reviewed by:	Almost everyone who counts
	(at various times, peter, jhb, matt, alfred, mini, bernd,
	and a cast of thousands)

	NOTE: this is still Beta code, and contains lots of debugging stuff.
	expect slight instability in signals..
2002-06-29 17:26:22 +00:00
Alfred Perlstein
016091145e more caddr_t removal. 2002-06-29 02:00:02 +00:00
Matthew Dillon
727300861d I Noticed a defect in the way wakeup() scans the tailq. Tor noticed an
even worse defect in wakeup_one().  This patch cleans up both.

Submitted by:	tegge
MFC after:	3 days
2002-06-24 00:14:36 +00:00
John Baldwin
9ba7fe1b76 - Catch up to new ktrace API.
- ktrace trace points in msleep() and cv_wait() no longer need Giant.
2002-06-07 05:39:16 +00:00
Julian Elischer
628855e758 CURSIG() is not a macro so rename it cursig().
Obtained from:	KSE tree
2002-05-29 23:44:32 +00:00
John Baldwin
cc5d39f81e Minor nit: get p pointer in msleep() from td->td_proc (where
td == curthread) rather than from curproc.
2002-05-23 04:14:18 +00:00
Alfred Perlstein
4d77a549fe Remove __P. 2002-03-19 21:25:46 +00:00
Peter Wemm
30171114b3 Fix a gcc-3.1+ warning.
warning: deprecated use of label at end of compound statement

ie: you cannot do this anymore:
switch(foo) {
....

default:
}
2002-03-19 11:02:06 +00:00
Poul-Henning Kamp
1cbb9c3b03 Convert p->p_runtime and PCPU(switchtime) to bintime format. 2002-02-22 13:32:01 +00:00
Julian Elischer
2c1007663f In a threaded world, differnt priorirites become properties of
different entities.  Make it so.

Reviewed by:	jhb@freebsd.org (john baldwin)
2002-02-11 20:37:54 +00:00
John Baldwin
c86b6ff551 Change the preemption code for software interrupt thread schedules and
mutex releases to not require flags for the cases when preemption is
not allowed:

The purpose of the MTX_NOSWITCH and SWI_NOSWITCH flags is to prevent
switching to a higher priority thread on mutex releease and swi schedule,
respectively when that switch is not safe.  Now that the critical section
API maintains a per-thread nesting count, the kernel can easily check
whether or not it should switch without relying on flags from the
programmer.  This fixes a few bugs in that all current callers of
swi_sched() used SWI_NOSWITCH, when in fact, only the ones called from
fast interrupt handlers and the swi_sched of softclock needed this flag.
Note that to ensure that swi_sched()'s in clock and fast interrupt
handlers do not switch, these handlers have to be explicitly wrapped
in critical_enter/exit pairs.  Presently, just wrapping the handlers is
sufficient, but in the future with the fully preemptive kernel, the
interrupt must be EOI'd before critical_exit() is called.  (critical_exit()
can switch due to a deferred preemption in a fully preemptive kernel.)

I've tested the changes to the interrupt code on i386 and alpha.  I have
not tested ia64, but the interrupt code is almost identical to the alpha
code, so I expect it will work fine.  PowerPC and ARM do not yet have
interrupt code in the tree so they shouldn't be broken.  Sparc64 is
broken, but that's been ok'd by jake and tmm who will be fixing the
interrupt code for sparc64 shortly.

Reviewed by:	peter
Tested on:	i386, alpha
2002-01-05 08:47:13 +00:00
John Baldwin
7e1f6dfe9d Modify the critical section API as follows:
- The MD functions critical_enter/exit are renamed to start with a cpu_
  prefix.
- MI wrapper functions critical_enter/exit maintain a per-thread nesting
  count and a per-thread critical section saved state set when entering
  a critical section while at nesting level 0 and restored when exiting
  to nesting level 0.  This moves the saved state out of spin mutexes so
  that interlocking spin mutexes works properly.
- Most low-level MD code that used critical_enter/exit now use
  cpu_critical_enter/exit.  MI code such as device drivers and spin
  mutexes use the MI wrappers.  Note that since the MI wrappers store
  the state in the current thread, they do not have any return values or
  arguments.
- mtx_intr_enable() is replaced with a constant CRITICAL_FORK which is
  assigned to curthread->td_savecrit during fork_exit().

Tested on:	i386, alpha
2001-12-18 00:27:18 +00:00
Luigi Rizzo
af1408e33f Add/correct description for some sysctl variables where it was missing.
The description field is unused in -stable, so the MFC there is equivalent
to a comment. It can be done at any time, i am just setting a reminder
in 45 days when hopefully we are past 4.5-release.

MFC after: 45 days
2001-12-16 16:07:20 +00:00