but with slightly cleaned up interfaces.
The KSE structure has become the same as the "per thread scheduler
private data" structure. In order to not make the diffs too great
one is #defined as the other at this time.
The KSE (or td_sched) structure is now allocated per thread and has no
allocation code of its own.
Concurrency for a KSEGRP is now kept track of via a simple pair of counters
rather than using KSE structures as tokens.
Since the KSE structure is different in each scheduler, kern_switch.c
is now included at the end of each scheduler. Nothing outside the
scheduler knows the contents of the KSE (aka td_sched) structure.
The fields in the ksegrp structure that are to do with the scheduler's
queueing mechanisms are now moved to the kg_sched structure.
(per ksegrp scheduler private data structure). In other words how the
scheduler queues and keeps track of threads is no-one's business except
the scheduler's. This should allow people to write experimental
schedulers with completely different internal structuring.
A scheduler call sched_set_concurrency(kg, N) has been added that
notifies teh scheduler that no more than N threads from that ksegrp
should be allowed to be on concurrently scheduled. This is also
used to enforce 'fainess' at this time so that a ksegrp with
10000 threads can not swamp a the run queue and force out a process
with 1 thread, since the current code will not set the concurrency above
NCPU, and both schedulers will not allow more than that many
onto the system run queue at a time. Each scheduler should eventualy develop
their own methods to do this now that they are effectively separated.
Rejig libthr's kernel interface to follow the same code paths as
linkse for scope system threads. This has slightly hurt libthr's performance
but I will work to recover as much of it as I can.
Thread exit code has been cleaned up greatly.
exit and exec code now transitions a process back to
'standard non-threaded mode' before taking the next step.
Reviewed by: scottl, peter
MFC after: 1 week
FULL_PREEMPTION is defined. Add a runtime warning to ULE if PREEMPTION is
enabled (code inspired by the PREEMPTION warning in kern_switch.c). This
is a possible MT5 candidate.
update tick count for userland in thread_userret. This change
also removes a "no upcall owned" panic because fuword() schedules
an upcall under heavily loaded, and code assumes there is no upcall
can occur.
Reported and Tested by: Peter Holm <peter@holm.cc>
The removed argument could trivially be derived from the remaining one.
That in turn should be the same as curthread, but it is possible that curthread could be expensive to derive on some syste,s so leave it as an argument.
Having both proc and thread as an argumen tjust gives an opportunity for
them to get out sync.
MFC after: 3 days
in diagnostics. It has outlived its usefulness and has started
causing panics for people who turn on DIAGNOSTIC, in what is otherwise
good code.
MFC after: 2 days
syscall can interrupt other thread's syscall in sleepq_catch_signals().
Current, all callers know thread_suspend_check may suspend thread
itself, so we need't to check return_instead for normal suspension
flags (no P_SINGLE_EXIT set).
Tested by: deischen
Reported by: Maarten L. Hekkelman <m.hekkelman@cmbi.kun.nl>
this in my tree for a while and in its disabled state there are no
issues. It isn't enabled yet because some drivers (in acpi) have side
effects in their probe routines that need to be resolved in some
manner before this can be turned on. The consensus at the last
developer's summit was to provide a static method for each driver
class that will return characteristics of the driver, one of which is
if can be reprobed idempotently.
address I've lost, that move the location information to the atttach
routine as well. While one could use devinfo to get this data, that
is difficult and error prone and subject to races for short lived
devices.
Would make a good MT5 candidate.
need of sched_lock in some places. Also in thread_userret, remove
spare thread allocation code, it is already done in thread_user_enter.
Reviewed by: julian
preemption and/or the rev 1.79 kern_switch.c change that was backed out.
The thread was being assigned to a runq without adding in the load, which
would cause the counter to hit -1.
pollfd's to avoid calling malloc() on small numbers of fd's. Because
smalltype's members have type char, its address might be misaligned
for a struct pollfd. Change the array of char to an array of struct
pollfd.
PR: kern/58214
Submitted by: Stefan Farfeleder <stefan@fafoe.narf.at>
Reviewed by: bde (a long time ago)
MFC after: 3 days
UNIX domain socket garbage collection implementation, as that risks
holding the mutex over potentially sleeping operations (as well as
introducing some nasty lock order issues, etc). unp_gc() will hold
the lock long enough to do necessary deferal checks and set that it's
running, but then release it until it needs to reset the gc state.
RELENG_5 candidate.
Discussed with: alfred
buffers with kqueue filters is no longer required: the kqueue framework
will guarantee that the mutex is held on entering the filter, either
due to a call from the socket code already holding the mutex, or by
explicitly acquiring it. This removes the last of the conditional
socket locking.
We were obtaining different spin mutexes (which disable interrupts after
aquisition) and spin waiting for delivery. For example, KSE processes
do LDT operations which use smp_rendezvous, while other parts of the
system are doing things like tlb shootdowns with a different mutex.
This patch uses the common smp_rendezvous mutex for all MD home-grown
IPIs that spinwait for delivery. Having the single mutex means that
the spinloop to aquire it will enable interrupts periodically, thus
avoiding the cross-ipi deadlock.
Obtained from: dwhite, alc
Reviewed by: jhb
in the shutdown_final state if the RB_NOSYNC flag is set.
The specific motivation in this case is that a system panic in an
interrupt context results in a call to module_shutdown(), which
calls g_modevent(), which calls g_malloc(..., M_WAITOK), which
results in a second panic. While g_modevent() could be fixed to
not call malloc() for MOD_SHUTDOWN events (which it doesn't handle
in any case), it is probably also a good idea to entirely skip the
execution of the module shutdown handlers after a panic.
This may be a MFC candidate for RELENG_5.
shutdown_pre_sync state if the RB_NOSYNC flag is set. This is the
likely cause of hangs after a system panic that are keeping crash
dumps from being done.
This is a MFC candidate for RELENG_5.
MFC after: 3 days
sockets are connection-oriented for the purposes of kqueue
registration. Since UDP sockets aren't connection-oriented, this
appeared to break a great many things, such as RPC-based
applications and services (i.e., NFS). Since jmg isn't around I'm
backing this out before too many more feet are shot, but intend to
investigate the right solution with him once he's available.
Apologies to: jmg
Discussed with: imp, scottl
is an effective band-aid for at least some of the scheduler corruption seen
recently. The real fix will involve protecting threads while they are
inconsistent, and will come later.
Submitted by: julian
If the bioq is empty, NULL is returned. Otherwise the front element
is removed and returned.
This can simplify locking in many drivers from:
lock()
bp = bioq_first(bq);
if (bp == NULL) {
unlock()
return
}
bioq_remove(bp, bq)
unlock
to:
lock()
bp = bioq_takefirst(bq);
unlock()
if (bp == NULL)
return;
