(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.
i386 cpu_thread_exit(). This resulted in a panic with WITNESS
since we need to hold Giant to call kmem_free(), and we weren't
helding it anymore in cpu_thread_exit(). We now do this from a
new MD function, cpu_thread_dtor(), called by thread_dtor().
Approved by: re@
Suggested by: jhb
data in the scheduler independant structures (proc, ksegrp, kse, thread).
- Implement unused stubs for this mechanism in sched_4bsd.
Approved by: re
Reviewed by: luigi, trb
Tested on: x86, alpha
also add rusage time in thread mailbox.
2. Minor change for thread limit code in thread_user_enter(),
fix typo in kse_release() last I committed.
Reviewed by: deischen, mini
kern.threads.max_threads_per_proc
kern.threads.max_groups_per_proc
2.Temporary disable borrower thread stash itself as
owner thread's spare thread in thread_exit(). there
is a race between owner thread and borrow thread:
an owner thread may allocate a spare thread as this:
if (td->td_standin == NULL)
td->standin = thread_alloc();
but thread_alloc() can block the thread, then a borrower
thread would possible stash it self as owner's spare
thread in thread_exit(), after owner is resumed, result
is a thread leak in kernel, double check in owner can
avoid the race, but it may be ugly and not worth to do.
so that there is ony one copy of it. Fix that one copy
so that KSEs with no mailbox in a KSE program are not a cause
of page faults (this can legitmatly happen).
Submitted by: (parts) davidxu
Add code to free KSEs and KSEGRPs on exit.
Sort KSE prototypes in proc.h.
Add the missing kse_exit() syscall.
ksetest now does not leak KSEs and KSEGRPS.
Submitted by: (parts) davidxu
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.
around limitations in the ia64 kernel stack handling code. Basically
preallocate a bunch of threads (and hence kstacks) while contigmalloc()
still works, and never free them back to the general memory pool. After
the system has been running for a while, contigmalloc() eventually fails
at a critical momemt and panics the system.
doesn't give them enough stack to do much before blowing away the pcb.
This adds MI and MD code to allow the allocation of an alternate kstack
who's size can be speficied when calling kthread_create. Passing the
value 0 prevents the alternate kstack from being created. Note that the
ia64 MD code is missing for now, and PowerPC was only partially written
due to the pmap.c being incomplete there.
Though this patch does not modify anything to make use of the alternate
kstack, acpi and usb are good candidates.
Reviewed by: jake, peter, jhb
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
if they are not going to cross over themselves. Also change how the list of
completed user threads is tracked and passed to the KSE. This is not
a change in design but rather the implementation of what was originally
envisionned.
- Use ucontext_t's to store KSE thread state.
- Synthesize state for the UTS upon each upcall, rather than
saving and copying a trapframe.
- Deliver signals to KSE-aware processes via upcall.
- Rename kse mailbox structure fields to be more BSD-like.
- Store the UTS's stack in struct proc in a stack_t.
Reviewed by: bde, deischen, julian
Approved by: -arch
