void
sched(void)
{
if(up) {
splhi();
procsave(up);
if(setlabel(&up->sched)) {
/* procrestore(up); */
spllo();
return;
}
gotolabel(&m->sched);
}
up = runproc();
up->state = Running;
up->mach = MACHP(m->machno); /* m might be a fixed address; use MACHP */
m->proc = up;
gotolabel(&up->sched);
}
void
debuggotolabel(Label *p)
{
Mach *m = machp();
if(0)hi("debuggotolabel");
iprint("gotolabel: pid %p rip %p sp %p\n",
m && m->externup? m->externup->pid : 0,
(void *)p->pc,
(void *)p->sp);
/*
*/
if (!p->pc)
die("PC IS ZERO!");
/* this is an example of putting a breakpoint
* here so we can capture a particular process.
* startup is very deterministic so this can
* be very useful. You can then attach with
* gdb and single step. In practice this helped us show
* that our return stack for sysrforkret was bogus.
if (m && m->externup && m->externup->pid == 6)
die("PID 6\n");
*/
gotolabel(p);
}
/*
* sleep if a condition is not true. Another process will
* awaken us after it sets the condition. When we awaken
* the condition may no longer be true.
*
* we lock both the process and the rendezvous to keep r->p
* and p->r synchronized.
*/
void
sleep(Rendez *r, int (*f)(void*), void *arg)
{
int s;
void (*pt)(Proc*, int, vlong);
s = splhi();
if(up->nlocks)
print("process %lud sleeps with %d locks held, last lock %#p locked at pc %#p, sleep called from %#p\n",
up->pid, up->nlocks, up->lastlock, up->lastlock->pc, getcallerpc(&r));
lock(r);
lock(&up->rlock);
if(r->p != nil){
print("double sleep called from %#p, %lud %lud\n", getcallerpc(&r), r->p->pid, up->pid);
dumpstack();
}
/*
* Wakeup only knows there may be something to do by testing
* r->p in order to get something to lock on.
* Flush that information out to memory in case the sleep is
* committed.
*/
r->p = up;
if((*f)(arg) || up->notepending){
/*
* if condition happened or a note is pending
* never mind
*/
r->p = nil;
unlock(&up->rlock);
unlock(r);
} else {
/*
* now we are committed to
* change state and call scheduler
*/
pt = proctrace;
if(pt != nil)
pt(up, SSleep, 0);
up->state = Wakeme;
up->r = r;
/* statistics */
m->cs++;
procsave(up);
if(setlabel(&up->sched)) {
/*
* here when the process is awakened
*/
procrestore(up);
spllo();
} else {
/*
* here to go to sleep (i.e. stop Running)
*/
unlock(&up->rlock);
unlock(r);
gotolabel(&m->sched);
}
}
if(up->notepending) {
up->notepending = 0;
splx(s);
interrupted();
}
splx(s);
}
void
nexterror(void)
{
assert(up->nerrlab > 0);
gotolabel(&up->errlab[--up->nerrlab]);
}
/*
* If changing this routine, look also at sleep(). It
* contains a copy of the guts of sched().
*/
void
sched(void)
{
Proc *p;
if(m->ilockdepth)
panic("cpu%d: ilockdepth %d, last lock %#p at %#p, sched called from %#p",
m->machno,
m->ilockdepth,
up != nil ? up->lastilock: nil,
(up != nil && up->lastilock != nil) ? up->lastilock->pc: 0,
getcallerpc(&p+2));
if(up != nil) {
/*
* Delay the sched until the process gives up the locks
* it is holding. This avoids dumb lock loops.
* Don't delay if the process is Moribund.
* It called sched to die.
* But do sched eventually. This avoids a missing unlock
* from hanging the entire kernel.
* But don't reschedule procs holding palloc or procalloc.
* Those are far too important to be holding while asleep.
*
* This test is not exact. There can still be a few instructions
* in the middle of taslock when a process holds a lock
* but Lock.p has not yet been initialized.
*/
if(up->nlocks)
if(up->state != Moribund)
if(up->delaysched < 20
|| palloc.Lock.p == up
|| procalloc.Lock.p == up){
up->delaysched++;
delayedscheds++;
return;
}
up->delaysched = 0;
splhi();
/* statistics */
m->cs++;
procsave(up);
if(setlabel(&up->sched)){
procrestore(up);
spllo();
return;
}
gotolabel(&m->sched);
}
p = runproc();
if(p->edf == nil){
updatecpu(p);
p->priority = reprioritize(p);
}
if(p != m->readied)
m->schedticks = m->ticks + HZ/10;
m->readied = nil;
up = p;
up->state = Running;
up->mach = MACHP(m->machno);
m->proc = up;
mmuswitch(up);
gotolabel(&up->sched);
}
void
nexterror(void)
{
Mach *m = machp();
/*debug*/gotolabel(&m->externup->errlab[--m->externup->nerrlab]);
}
/*
* If changing this routine, look also at sleep(). It
* contains a copy of the guts of sched().
*/
void
sched(void)
{
Mach *m = machp();
Proc *p;
if(m->ilockdepth)
panic("cpu%d: ilockdepth %d, last lock %#p at %#p, sched called from %#p",
m->machno,
m->ilockdepth,
m->externup? m->externup->lastilock: nil,
(m->externup && m->externup->lastilock)? m->externup->lastilock->_pc: 0,
getcallerpc(&p+2));
kstackok();
if(m->externup){
/*
* Delay the sched until the process gives up the locks
* it is holding. This avoids dumb lock loops.
* Don't delay if the process is Moribund.
* It called sched to die.
* But do sched eventually. This avoids a missing unlock
* from hanging the entire kernel.
* But don't reschedule procs holding palloc or procalloc.
* Those are far too important to be holding while asleep.
*
* This test is not exact. There can still be a few
* instructions in the middle of taslock when a process
* holds a lock but Lock.p has not yet been initialized.
*/
if(m->externup->nlocks)
if(m->externup->state != Moribund)
if(m->externup->delaysched < 20
|| pga.Lock.p == m->externup
|| procalloc.Lock.p == m->externup){
m->externup->delaysched++;
run.delayedscheds++;
return;
}
m->externup->delaysched = 0;
splhi();
/* statistics */
if(m->externup->nqtrap == 0 && m->externup->nqsyscall == 0)
m->externup->nfullq++;
m->cs++;
procsave(m->externup);
mmuflushtlb(m->pml4->pa);
if(setlabel(&m->externup->sched)){
procrestore(m->externup);
spllo();
return;
}
/*debug*/gotolabel(&m->sched);
}
m->inidle = 1;
p = runproc(); /* core 0 never returns */
m->inidle = 0;
if(!p->edf){
updatecpu(p);
p->priority = reprioritize(p);
}
if(nosmp){
if(p != m->readied)
m->schedticks = m->ticks + HZ/10;
m->readied = 0;
}
m->externup = p;
m->qstart = m->ticks;
m->externup->nqtrap = 0;
m->externup->nqsyscall = 0;
m->externup->state = Running;
//m->externup->mach = m;
m->externup->mach = sys->machptr[m->machno];
m->proc = m->externup;
// iprint("m->externup->sched.sp %p * %p\n", up->sched.sp,
// *(void **) m->externup->sched.sp);
mmuswitch(m->externup);
assert(!m->externup->wired || m->externup->wired == m);
if (0) hi("gotolabel\n");
/*debug*/gotolabel(&m->externup->sched);
}
/*
* sleep if a condition is not true. Another process will
* awaken us after it sets the condition. When we awaken
* the condition may no longer be true.
*
* we lock both the process and the rendezvous to keep r->p
* and p->r synchronized.
*/
void
sleep(Rendez *r, int (*f)(void*), void *arg)
{
Mach *m = machp();
Mpl pl;
pl = splhi();
if(m->externup->nlocks)
print("process %d sleeps with %d locks held, last lock %#p locked at pc %#p, sleep called from %#p\n",
m->externup->pid, m->externup->nlocks, m->externup->lastlock, m->externup->lastlock->_pc, getcallerpc(&r));
lock(r);
lock(&m->externup->rlock);
if(r->_p){
print("double sleep called from %#p, %d %d\n",
getcallerpc(&r), r->_p->pid, m->externup->pid);
dumpstack();
}
/*
* Wakeup only knows there may be something to do by testing
* r->p in order to get something to lock on.
* Flush that information out to memory in case the sleep is
* committed.
*/
r->_p = m->externup;
if((*f)(arg) || m->externup->notepending){
/*
* if condition happened or a note is pending
* never mind
*/
r->_p = nil;
unlock(&m->externup->rlock);
unlock(r);
} else {
/*
* now we are committed to
* change state and call scheduler
*/
if(m->externup->trace)
proctrace(m->externup, SSleep, 0);
m->externup->state = Wakeme;
m->externup->r = r;
/* statistics */
m->cs++;
procsave(m->externup);
mmuflushtlb(m->pml4->pa);
if(setlabel(&m->externup->sched)) {
/*
* here when the process is awakened
*/
procrestore(m->externup);
spllo();
} else {
/*
* here to go to sleep (i.e. stop Running)
*/
unlock(&m->externup->rlock);
unlock(r);
/*debug*/gotolabel(&m->sched);
}
}
if(m->externup->notepending) {
m->externup->notepending = 0;
splx(pl);
if(m->externup->procctl == Proc_exitme && m->externup->closingfgrp)
forceclosefgrp();
error(Eintr);
}
splx(pl);
}
void
nexterror(void)
{
gotolabel(&up->errlab[--up->nerrlab]);
}
void
nexterror(void)
{
Proc *up = externup();
/*debug*/gotolabel(&up->errlab[--up->nerrlab]);
}