proc_enterpgrp() with proc_leavepgrp() to free process group and/or
session without proc_lock held.
- Rename SESSHOLD() and SESSRELE() to to proc_sesshold() and
proc_sessrele(). The later releases proc_lock now.
Quick OK by <ad>.
for now. This will prevent signals from waking them. Adjust
exit_lwps() to explicitly add LW_SINTR to all of them, so that
the process exit code can wake them up.
This is needed as threads in both of these wait channels die once
they are woken. So they aren't interruptable in the typical sense.
I am now able to suspend & resume firefox successfully now.
one of the following:
- Holding kernel_lock (indicating that the code is not MT safe).
- Bracketing critical sections with kpreempt_disable/kpreempt_enable.
- Holding the interrupt priority level above IPL_NONE.
Statistics on kernel preemption are reported via event counters, and
where preemption is deferred for some reason, it's also reported via
lockstat. The LWP priority at which preemption is triggered is tuneable
via sysctl.
we no longer need to guard against access from hardware interrupt handlers.
Additionally, if cloning a process with CLONE_SIGHAND, arrange to have the
child process share the parent's lock so that signal state may be kept in
sync. Partially addresses PR kern/37437.
proclist_mutex and proclist_lock into a single adaptive mutex (proc_lock).
Implications:
- Inspecting process state requires thread context, so signals can no longer
be sent from a hardware interrupt handler. Signal activity must be
deferred to a soft interrupt or kthread.
- As the proc state locking is simplified, it's now safe to take exit()
and wait() out from under kernel_lock.
- The system spends less time at IPL_SCHED, and there is less lock activity.
int foo(struct lwp *l, void *v, register_t *retval)
to:
int foo(struct lwp *l, const struct foo_args *uap, register_t *retval)
Fixup compat code to not write into 'uap' and (in some cases) to actually
pass a correctly formatted 'uap' structure with the right name to the
next routine.
A few 'compat' routines that just call standard ones have been deleted.
All the 'compat' code compiles (along with the kernels required to test
build it).
98% done by automated scripts.
by yamt@.
- Introduce SOBJ_SLEEPQ_LIFO, and use for LWPs sleeping via _lwp_park.
libpthread enqueues most waiters in LIFO order to try and wake LWPs that
ran recently, since their working set is more likely to be in cache.
Matching the order of insertion reduces the time spent searching queues
in the kernel.
- Do not boost the priority of LWPs sleeping in _lwp_park, just let them
sleep at their user priority level. LWPs waiting for some I/O event in
the kernel still wait with kernel priority and get woken more quickly.
This needs more evaluation and is to be revisited, but the effect on a
variety of benchmarks is positive.
- When waking LWPs, do not send an IPI to remote CPUs or arrange for the
current LWP to be preempted unless (a) the thread being awoken has kernel
priority and has higher priority than the currently running thread or (b)
the remote CPU is idle.
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.
pooka