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kernel: don't sched() for clock interrupt when up->state != Running

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When we get a clock interrupt, we should not
call sched() when the process is not in "Running" state
as it is already committed to call sched() itself.

(An example is qlock(), just after the unlock() call).

As this is basically the same check as done in
preempted(), unify both and add a "clockintr"
argument to preempted().

Then most trap handlers just become:

preempted(irq());

Also, we do not want to call preempted() for traps,
as the trap handler has just setup some machine
state to resolve the trap. We can wait for the
clock interrupt if we really need the preempt.
This commit is contained in:
cinap_lenrek 2024-01-04 04:33:29 +00:00
parent 02015f69f6
commit 29e9c7bf01
14 changed files with 30 additions and 112 deletions
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5
sys/src/9/arm64/trap.c
View file

@ -124,10 +124,7 @@ trap(Ureg *ureg)
case 0x00: // unknown
if(intr == 1){
f = fpukenter(ureg);
if(!irq(ureg))
preempted();
else if(up != nil && up->delaysched)
sched();
preempted(irq(ureg));
break;
}
if(intr == 3){

5
sys/src/9/bcm/trap.c
View file

@ -166,10 +166,7 @@ trap(Ureg *ureg)
ureg->psr & PsrMask);
break;
case PsrMirq:
if(!irq(ureg))
preempted();
else if(up != nil && up->delaysched)
sched(); /* can cause more traps */
preempted(irq(ureg));
break;
case PsrMabt: /* prefetch fault */
x = ifsrget();

10
sys/src/9/cycv/intr.c
View file

@ -109,13 +109,5 @@ intr(Ureg *ureg)
i->f(ureg, i->arg);
mpcore[ICCEOIR] = v;
if(up != nil){
if(irq == TIMERIRQ){
if(up->delaysched){
splhi();
sched();
}
}else
preempted();
}
preempted(irq == TIMERIRQ);
}

10
sys/src/9/kw/trap.c
View file

@ -391,15 +391,9 @@ trap(Ureg *ureg)
panic("unknown trap %ld", ureg->type);
break;
case PsrMirq:
ldrexvalid = 0;
// splflo(); /* allow fast interrupts */
if(!intrs(ureg, Irqlo))
preempted();
else if(up != nil && up->delaysched){
ldrexvalid = 0;
sched();
}
m->intr++;
ldrexvalid = 0;
preempted(intrs(ureg, Irqlo));
break;
case PsrMabt: /* prefetch fault */
ldrexvalid = 0;

6
sys/src/9/mt7688/irq.c
View file

@ -221,12 +221,6 @@ intr(Ureg* ur)
if(cause != 0)
iprint("unhandled interrupts %lux\n", cause);
/* preemptive scheduling */
if(up != nil && !clockintr)
preempted();
/* if it was a clockintr, sched will be called at end of trap() */
return clockintr;
}

11
sys/src/9/mt7688/trap.c
View file

@ -147,7 +147,7 @@ kvce(Ureg *ur, int ecode)
void
trap(Ureg *ur)
{
int ecode, clockintr, user, cop, x, fpchk;
int ecode, user, cop, x, fpchk;
ulong fpfcr31;
char buf[2*ERRMAX], buf1[ERRMAX], *fpexcep;
static int dumps;
@ -170,10 +170,9 @@ trap(Ureg *ur)
panic("trap: tlb shutdown");
ecode = (ur->cause>>2)&EXCMASK;
fpchk = 0;
clockintr = 0;
switch(ecode){
case CINT:
clockintr = intr(ur);
preempted(intr(ur));
break;
case CFPE:
@ -260,12 +259,6 @@ trap(Ureg *ur)
splhi();
/* delaysched set because we held a lock or because our quantum ended */
if(up && up->delaysched && clockintr){
sched();
splhi();
}
if(user){
notify(ur);
/* replicate fpstate to ureg status */

11
sys/src/9/mtx/trap.c
View file

@ -223,9 +223,11 @@ trap(Ureg *ureg)
switch(ecode) {
case CEI:
intr(ureg);
preempted(0);
break;
case CDEC:
clockintr(ureg);
preempted(1);
break;
case CSYSCALL:
if(!user)
@ -295,12 +297,6 @@ trap(Ureg *ureg)
/* restoreureg must execute at high IPL */
splhi();
/* delaysched set because we held a lock or because our quantum ended */
if(up && up->delaysched && ecode == CDEC){
sched();
splhi();
}
if(user) {
notify(ureg);
if(up->fpstate == FPinactive)
@ -391,9 +387,6 @@ intr(Ureg *ureg)
}
if(ctl->eoi)
ctl->eoi(vno);
if(up)
preempted();
}
char*

7
sys/src/9/omap/trap.c
View file

@ -482,12 +482,7 @@ trap(Ureg *ureg)
break;
case PsrMirq:
ldrexvalid = 0;
if(!irq(ureg))
preempted();
else if(up != nil && up->delaysched){
ldrexvalid = 0;
sched();
}
preempted(irq(ureg));
m->intr++;
break;
case PsrMabt: /* prefetch fault */

11
sys/src/9/pc/irq.c
View file

@ -63,16 +63,7 @@ irqhandled(Ureg *ureg, int vno)
if(ctl->eoi != nil)
(*ctl->eoi)(vno);
intrtime(m, vno);
if(up != nil){
if(ctl == vclock){
/* delaysched set because we held a lock or because our quantum ended */
if(up->delaysched)
sched();
} else {
preempted();
}
}
preempted(ctl == vclock);
return 1;
}

23
sys/src/9/port/proc.c
View file

@ -252,24 +252,23 @@ hzsched(void)
}
/*
* here at the end of non-clock interrupts to see if we should preempt the
* current process. Returns 1 if preempted, 0 otherwise.
* here at the end of interrupts to see if we should preempt the
* current process.
*/
int
preempted(void)
void
preempted(int clockintr)
{
if(up != nil && up->state == Running)
if(up->preempted == 0)
if(anyhigher())
if(!active.exiting){
if(up == nil || up->state != Running || active.exiting)
return;
if(!clockintr){
if(up->preempted || !anyhigher())
return;
m->readied = nil; /* avoid cooperative scheduling */
up->preempted = 1;
sched();
splhi();
up->preempted = 0;
return 1;
}
return 0;
} else if(up->delaysched)
sched(); /* quantum ended or we held a lock */
}
/*

8
sys/src/9/ppc/trap.c
View file

@ -155,9 +155,11 @@ trap(Ureg *ureg)
case CEI:
m->intr++;
intr(ureg);
preempted(0);
break;
case CDEC:
clockintr(ureg);
preempted(1);
break;
case CDSI:
m->pfault++;
@ -279,12 +281,6 @@ trap(Ureg *ureg)
/* restoreureg must execute at high IPL */
splhi();
/* delaysched set because we held a lock or because our quantum ended */
if(up && up->delaysched && ecode == CDEC){
sched();
splhi();
}
if(user) {
if (up->fpstate == FPactive && (ureg->srr1 & MSR_FP) == 0){
postnote(up, 1, buf, NDebug);

15
sys/src/9/sgi/trap.c
View file

@ -155,7 +155,7 @@ kvce(Ureg *ur, int ecode)
void
trap(Ureg *ur)
{
int ecode, clockintr, user, cop, x, fpchk;
int ecode, user, cop, x, fpchk;
ulong fpfcr31;
char buf[2*ERRMAX], buf1[ERRMAX], *fpexcep;
static int dumps;
@ -178,10 +178,9 @@ trap(Ureg *ur)
panic("trap: tlb shutdown");
ecode = (ur->cause>>2)&EXCMASK;
fpchk = 0;
clockintr = 0;
switch(ecode){
case CINT:
clockintr = intr(ur);
preempted(intr(ur));
break;
case CFPE:
@ -276,12 +275,6 @@ trap(Ureg *ur)
splhi();
/* delaysched set because we held a lock or because our quantum ended */
if(up && up->delaysched && clockintr){
sched();
splhi();
}
if(user){
notify(ur);
/* replicate fpstate to ureg status */
@ -357,10 +350,6 @@ intr(Ureg *ur)
if(cause != 0)
iprint("unhandled interrupts %lux\n", cause);
/* preemptive scheduling */
if(up != nil && !clockintr)
preempted();
/* if it was a clockintr, sched will be called at end of trap() */
return clockintr;
}

15
sys/src/9/teg2/trap.c
View file

@ -637,6 +637,7 @@ irq(Ureg* ureg)
Intrcpuregs *icp = (Intrcpuregs *)soc.intr;
Vctl *v;
m->intr++;
ticks = perfticks();
handled = 0;
ack = intack(icp);
@ -814,7 +815,7 @@ datafault(Ureg *ureg, int user)
void
trap(Ureg *ureg)
{
int clockintr, user, rem;
int user, rem;
uintptr va, ifar, ifsr;
splhi(); /* paranoia */
@ -841,17 +842,13 @@ trap(Ureg *ureg)
else
ureg->pc -= 4;
clockintr = 0; /* if set, may call sched() before return */
switch(ureg->type){
default:
panic("unknown trap; type %#lux, psr mode %#lux", ureg->type,
ureg->psr & PsrMask);
break;
case PsrMirq:
m->intr++;
clockintr = irq(ureg);
if(0 && up && !clockintr)
preempted(); /* this causes spurious suicides */
preempted(irq(ureg));
break;
case PsrMabt: /* prefetch (instruction) fault */
va = ureg->pc;
@ -908,12 +905,6 @@ trap(Ureg *ureg)
}
splhi();
/* delaysched set because we held a lock or because our quantum ended */
if(up && up->delaysched && clockintr){
sched(); /* can cause more traps */
splhi();
}
if(user){
if(up->procctl || up->nnote)
notify(ureg);

5
sys/src/9/zynq/trap.c
View file

@ -182,10 +182,7 @@ trap(Ureg *ureg)
break;
case PsrMirq:
ureg->pc -= 4;
if(!intr(ureg))
preempted();
else if(up != nil && up->delaysched)
sched();
preempted(intr(ureg));
break;
default:
iprint("cpu%d: unknown trap type %ulx\n", m->machno, ureg->type);