// Mark g ready to run. Sched is already locked.
// G might be running already and about to stop.
// The sched lock protects g->status from changing underfoot.
static void
readylocked(G *g)
{
if(g->m){
// Running on another machine.
// Ready it when it stops.
g->readyonstop = 1;
return;
}
// Mark runnable.
if(g->status == Grunnable || g->status == Grunning) {
runtime·printf("goroutine %d has status %d\n", g->goid, g->status);
runtime·throw("bad g->status in ready");
}
g->status = Grunnable;
gput(g);
matchmg();
}
// One round of scheduler: find a goroutine and run it.
// The argument is the goroutine that was running before
// schedule was called, or nil if this is the first call.
// Never returns.
static void
schedule(G *gp)
{
int32 hz;
uint32 v;
schedlock();
if(gp != nil) {
// Just finished running gp.
gp->m = nil;
runtime·sched.grunning--;
// atomic { mcpu-- }
v = runtime·xadd(&runtime·sched.atomic, -1<<mcpuShift);
if(atomic_mcpu(v) > maxgomaxprocs)
runtime·throw("negative mcpu in scheduler");
switch(gp->status){
case Grunnable:
case Gdead:
// Shouldn't have been running!
runtime·throw("bad gp->status in sched");
case Grunning:
gp->status = Grunnable;
gput(gp);
break;
case Gmoribund:
gp->status = Gdead;
if(gp->lockedm) {
gp->lockedm = nil;
m->lockedg = nil;
}
gp->idlem = nil;
unwindstack(gp, nil);
gfput(gp);
if(--runtime·sched.gcount == 0)
runtime·exit(0);
break;
}
if(gp->readyonstop){
gp->readyonstop = 0;
readylocked(gp);
}
} else if(m->helpgc) {
// Bootstrap m or new m started by starttheworld.
// atomic { mcpu-- }
v = runtime·xadd(&runtime·sched.atomic, -1<<mcpuShift);
if(atomic_mcpu(v) > maxgomaxprocs)
runtime·throw("negative mcpu in scheduler");
// Compensate for increment in starttheworld().
runtime·sched.grunning--;
m->helpgc = 0;
} else if(m->nextg != nil) {
// New m started by matchmg.
} else {
runtime·throw("invalid m state in scheduler");
}
// Find (or wait for) g to run. Unlocks runtime·sched.
gp = nextgandunlock();
gp->readyonstop = 0;
gp->status = Grunning;
m->curg = gp;
gp->m = m;
// Check whether the profiler needs to be turned on or off.
hz = runtime·sched.profilehz;
if(m->profilehz != hz)
runtime·resetcpuprofiler(hz);
if(gp->sched.pc == (byte*)runtime·goexit) { // kickoff
runtime·gogocall(&gp->sched, (void(*)(void))gp->entry);
}
runtime·gogo(&gp->sched, 0);
}
// One round of scheduler: find a goroutine and run it.
// The argument is the goroutine that was running before
// schedule was called, or nil if this is the first call.
// Never returns.
static void
schedule(G *gp)
{
int32 hz;
schedlock();
if(gp != nil) {
if(runtime·sched.predawn)
runtime·throw("init rescheduling");
// Just finished running gp.
gp->m = nil;
runtime·sched.mcpu--;
if(runtime·sched.mcpu < 0)
runtime·throw("runtime·sched.mcpu < 0 in scheduler");
switch(gp->status){
case Grunnable:
case Gdead:
// Shouldn't have been running!
runtime·throw("bad gp->status in sched");
case Grunning:
gp->status = Grunnable;
gput(gp);
break;
case Gmoribund:
gp->status = Gdead;
if(gp->lockedm) {
gp->lockedm = nil;
m->lockedg = nil;
}
gp->idlem = nil;
unwindstack(gp, nil);
gfput(gp);
if(--runtime·sched.gcount == 0)
runtime·exit(0);
break;
}
if(gp->readyonstop){
gp->readyonstop = 0;
readylocked(gp);
}
}
// Find (or wait for) g to run. Unlocks runtime·sched.
gp = nextgandunlock();
gp->readyonstop = 0;
gp->status = Grunning;
m->curg = gp;
gp->m = m;
// Check whether the profiler needs to be turned on or off.
hz = runtime·sched.profilehz;
if(m->profilehz != hz)
runtime·resetcpuprofiler(hz);
if(gp->sched.pc == (byte*)runtime·goexit) { // kickoff
runtime·gogocall(&gp->sched, (void(*)(void))gp->entry);
}
runtime·gogo(&gp->sched, 0);
}