void
runtime·stoptheworld(void)
{
uint32 v;
schedlock();
runtime·gcwaiting = 1;
setmcpumax(1);
// while mcpu > 1
for(;;) {
v = runtime·sched.atomic;
if(atomic_mcpu(v) <= 1)
break;
// It would be unsafe for multiple threads to be using
// the stopped note at once, but there is only
// ever one thread doing garbage collection.
runtime·noteclear(&runtime·sched.stopped);
if(atomic_waitstop(v))
runtime·throw("invalid waitstop");
// atomic { waitstop = 1 }, predicated on mcpu <= 1 check above
// still being true.
if(!runtime·cas(&runtime·sched.atomic, v, v+(1<<waitstopShift)))
continue;
schedunlock();
runtime·notesleep(&runtime·sched.stopped);
schedlock();
}
runtime·singleproc = runtime·gomaxprocs == 1;
schedunlock();
}
void
runtime·starttheworld(bool extra)
{
M *m;
schedlock();
runtime·gcwaiting = 0;
setmcpumax(runtime·gomaxprocs);
matchmg();
if(extra && canaddmcpu()) {
// Start a new m that will (we hope) be idle
// and so available to help when the next
// garbage collection happens.
// canaddmcpu above did mcpu++
// (necessary, because m will be doing various
// initialization work so is definitely running),
// but m is not running a specific goroutine,
// so set the helpgc flag as a signal to m's
// first schedule(nil) to mcpu-- and grunning--.
m = runtime·newm();
m->helpgc = 1;
runtime·sched.grunning++;
}
schedunlock();
}
// The main goroutine.
void
runtime_main(void)
{
// Lock the main goroutine onto this, the main OS thread,
// during initialization. Most programs won't care, but a few
// do require certain calls to be made by the main thread.
// Those can arrange for main.main to run in the main thread
// by calling runtime.LockOSThread during initialization
// to preserve the lock.
runtime_LockOSThread();
// From now on, newgoroutines may use non-main threads.
setmcpumax(runtime_gomaxprocs);
runtime_sched.init = true;
scvg = __go_go(runtime_MHeap_Scavenger, nil);
main_init();
runtime_sched.init = false;
if(!runtime_sched.lockmain)
runtime_UnlockOSThread();
// For gccgo we have to wait until after main is initialized
// to enable GC, because initializing main registers the GC
// roots.
mstats.enablegc = 1;
// The deadlock detection has false negatives.
// Let scvg start up, to eliminate the false negative
// for the trivial program func main() { select{} }.
runtime_gosched();
main_main();
runtime_exit(0);
for(;;)
*(int32*)0 = 0;
}
// The main goroutine.
void
runtime·main(void)
{
// Lock the main goroutine onto this, the main OS thread,
// during initialization. Most programs won't care, but a few
// do require certain calls to be made by the main thread.
// Those can arrange for main.main to run in the main thread
// by calling runtime.LockOSThread during initialization
// to preserve the lock.
runtime·LockOSThread();
// From now on, newgoroutines may use non-main threads.
setmcpumax(runtime·gomaxprocs);
runtime·sched.init = true;
scvg = runtime·newproc1((byte*)runtime·MHeap_Scavenger, nil, 0, 0, runtime·main);
main·init();
runtime·sched.init = false;
if(!runtime·sched.lockmain)
runtime·UnlockOSThread();
// The deadlock detection has false negatives.
// Let scvg start up, to eliminate the false negative
// for the trivial program func main() { select{} }.
runtime·gosched();
main·main();
runtime·exit(0);
for(;;)
*(int32*)runtime·main = 0;
}
// The bootstrap sequence is:
//
// call osinit
// call schedinit
// make & queue new G
// call runtime_mstart
//
// The new G calls runtime_main.
void
runtime_schedinit(void)
{
int32 n;
const byte *p;
m = &runtime_m0;
g = &runtime_g0;
m->g0 = g;
m->curg = g;
g->m = m;
initcontext();
inittlssize();
m->nomemprof++;
runtime_mallocinit();
mcommoninit(m);
runtime_goargs();
runtime_goenvs();
// For debugging:
// Allocate internal symbol table representation now,
// so that we don't need to call malloc when we crash.
// runtime_findfunc(0);
runtime_gomaxprocs = 1;
p = runtime_getenv("GOMAXPROCS");
if(p != nil && (n = runtime_atoi(p)) != 0) {
if(n > maxgomaxprocs)
n = maxgomaxprocs;
runtime_gomaxprocs = n;
}
// wait for the main goroutine to start before taking
// GOMAXPROCS into account.
setmcpumax(1);
runtime_singleproc = runtime_gomaxprocs == 1;
canaddmcpu(); // mcpu++ to account for bootstrap m
m->helpgc = 1; // flag to tell schedule() to mcpu--
runtime_sched.grunning++;
// Can not enable GC until all roots are registered.
// mstats.enablegc = 1;
m->nomemprof--;
}
// The bootstrap sequence is:
//
// call osinit
// call schedinit
// make & queue new G
// call runtime·mstart
//
// The new G calls runtime·main.
void
runtime·schedinit(void)
{
int32 n;
byte *p;
m->nomemprof++;
runtime·mprofinit();
runtime·mallocinit();
mcommoninit(m);
runtime·goargs();
runtime·goenvs();
// For debugging:
// Allocate internal symbol table representation now,
// so that we don't need to call malloc when we crash.
// runtime·findfunc(0);
runtime·gomaxprocs = 1;
p = runtime·getenv("GOMAXPROCS");
if(p != nil && (n = runtime·atoi(p)) != 0) {
if(n > maxgomaxprocs)
n = maxgomaxprocs;
runtime·gomaxprocs = n;
}
// wait for the main goroutine to start before taking
// GOMAXPROCS into account.
setmcpumax(1);
runtime·singleproc = runtime·gomaxprocs == 1;
canaddmcpu(); // mcpu++ to account for bootstrap m
m->helpgc = 1; // flag to tell schedule() to mcpu--
runtime·sched.grunning++;
mstats.enablegc = 1;
m->nomemprof--;
if(raceenabled)
runtime·raceinit();
}
// Implementation of runtime.GOMAXPROCS.
// delete when scheduler is stronger
int32
runtime·gomaxprocsfunc(int32 n)
{
int32 ret;
uint32 v;
schedlock();
ret = runtime·gomaxprocs;
if(n <= 0)
n = ret;
if(n > maxgomaxprocs)
n = maxgomaxprocs;
runtime·gomaxprocs = n;
if(runtime·gomaxprocs > 1)
runtime·singleproc = false;
if(runtime·gcwaiting != 0) {
if(atomic_mcpumax(runtime·sched.atomic) != 1)
runtime·throw("invalid mcpumax during gc");
schedunlock();
return ret;
}
setmcpumax(n);
// If there are now fewer allowed procs
// than procs running, stop.
v = runtime·atomicload(&runtime·sched.atomic);
if(atomic_mcpu(v) > n) {
schedunlock();
runtime·gosched();
return ret;
}
// handle more procs
matchmg();
schedunlock();
return ret;
}
void
runtime·starttheworld(void)
{
M *mp;
int32 max;
// Figure out how many CPUs GC could possibly use.
max = runtime·gomaxprocs;
if(max > runtime·ncpu)
max = runtime·ncpu;
if(max > MaxGcproc)
max = MaxGcproc;
schedlock();
runtime·gcwaiting = 0;
setmcpumax(runtime·gomaxprocs);
matchmg();
if(runtime·gcprocs() < max && canaddmcpu()) {
// If GC could have used another helper proc, start one now,
// in the hope that it will be available next time.
// It would have been even better to start it before the collection,
// but doing so requires allocating memory, so it's tricky to
// coordinate. This lazy approach works out in practice:
// we don't mind if the first couple gc rounds don't have quite
// the maximum number of procs.
// canaddmcpu above did mcpu++
// (necessary, because m will be doing various
// initialization work so is definitely running),
// but m is not running a specific goroutine,
// so set the helpgc flag as a signal to m's
// first schedule(nil) to mcpu-- and grunning--.
mp = runtime·newm();
mp->helpgc = 1;
runtime·sched.grunning++;
}
schedunlock();
}
// The bootstrap sequence is:
//
// call osinit
// call schedinit
// make & queue new G
// call runtime·mstart
//
// The new G calls runtime·main.
void
runtime·schedinit(void)
{
int32 n;
byte *p;
m->nomemprof++;
runtime·mallocinit();
mcommoninit(m);
runtime·goargs();
runtime·goenvs();
// For debugging:
// Allocate internal symbol table representation now,
// so that we don't need to call malloc when we crash.
// runtime·findfunc(0);
runtime·gomaxprocs = 1;
p = runtime·getenv("GOMAXPROCS");
if(p != nil && (n = runtime·atoi(p)) != 0) {
if(n > maxgomaxprocs)
n = maxgomaxprocs;
runtime·gomaxprocs = n;
}
setmcpumax(runtime·gomaxprocs);
runtime·singleproc = runtime·gomaxprocs == 1;
canaddmcpu(); // mcpu++ to account for bootstrap m
m->helpgc = 1; // flag to tell schedule() to mcpu--
runtime·sched.grunning++;
mstats.enablegc = 1;
m->nomemprof--;
scvg = runtime·newproc1((byte*)runtime·MHeap_Scavenger, nil, 0, 0, runtime·schedinit);
}
