freebsd-dev/sys/kern/kern_idle.c
Julian Elischer ad1e7d285a 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.
2006-12-06 06:34:57 +00:00

128 lines
3.4 KiB
C

/*-
* Copyright (C) 2000-2004 The FreeBSD Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/unistd.h>
#ifdef SMP
#include <sys/smp.h>
#endif
static void idle_setup(void *dummy);
SYSINIT(idle_setup, SI_SUB_SCHED_IDLE, SI_ORDER_FIRST, idle_setup, NULL)
static void idle_proc(void *dummy);
/*
* Set up per-cpu idle process contexts. The AP's shouldn't be running or
* accessing their idle processes at this point, so don't bother with
* locking.
*/
static void
idle_setup(void *dummy)
{
#ifdef SMP
struct pcpu *pc;
#endif
struct proc *p;
struct thread *td;
int error;
#ifdef SMP
SLIST_FOREACH(pc, &cpuhead, pc_allcpu) {
error = kthread_create(idle_proc, NULL, &p,
RFSTOPPED | RFHIGHPID, 0, "idle: cpu%d", pc->pc_cpuid);
pc->pc_idlethread = FIRST_THREAD_IN_PROC(p);
#else
error = kthread_create(idle_proc, NULL, &p,
RFSTOPPED | RFHIGHPID, 0, "idle");
PCPU_SET(idlethread, FIRST_THREAD_IN_PROC(p));
#endif
if (error)
panic("idle_setup: kthread_create error %d\n", error);
PROC_LOCK(p);
p->p_flag |= P_NOLOAD;
mtx_lock_spin(&sched_lock);
td = FIRST_THREAD_IN_PROC(p);
TD_SET_CAN_RUN(td);
td->td_flags |= TDF_IDLETD;
sched_class(td, PRI_IDLE);
sched_prio(td, PRI_MAX_IDLE);
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
#ifdef SMP
}
#endif
}
/*
* The actual idle process.
*/
static void
idle_proc(void *dummy)
{
struct proc *p;
struct thread *td;
#ifdef SMP
cpumask_t mycpu;
#endif
td = curthread;
p = td->td_proc;
#ifdef SMP
mycpu = PCPU_GET(cpumask);
mtx_lock_spin(&sched_lock);
idle_cpus_mask |= mycpu;
mtx_unlock_spin(&sched_lock);
#endif
for (;;) {
mtx_assert(&Giant, MA_NOTOWNED);
while (sched_runnable() == 0)
cpu_idle();
mtx_lock_spin(&sched_lock);
#ifdef SMP
idle_cpus_mask &= ~mycpu;
#endif
mi_switch(SW_VOL, NULL);
#ifdef SMP
idle_cpus_mask |= mycpu;
#endif
mtx_unlock_spin(&sched_lock);
}
}