runtime: add atomics to fix arm

R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/7429046

diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index b0511cacbabd964c4cdf434e3e58956b031d2b37..6b9f8eae800ae735a1408dc2008c02d3bececa21 100644 (file)
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -45,7 +45,7 @@ struct Sched {
 
        int32   stopwait;
        Note    stopnote;
-       bool    sysmonwait;
+       uint32  sysmonwait;
        Note    sysmonnote;
 
        int32   profilehz;      // cpu profiling rate
@@ -59,7 +59,7 @@ Sched runtime·sched;
 int32  runtime·gomaxprocs;
 bool   runtime·singleproc;
 bool   runtime·iscgo;
-int32  runtime·gcwaiting;
+uint32 runtime·gcwaiting;
 M      runtime·m0;
 G      runtime·g0;     // idle goroutine for m0
 G*     runtime·allg;
@@ -277,7 +277,7 @@ runtime·ready(G *gp)
        }
        gp->status = Grunnable;
        runqput(m->p, gp);
-       if(runtime·sched.npidle != 0 && runtime·sched.nmspinning == 0)  // TODO: fast atomic
+       if(runtime·atomicload(&runtime·sched.npidle) != 0 && runtime·atomicload(&runtime·sched.nmspinning) == 0)  // TODO: fast atomic
                wakep();
 }
 
@@ -842,7 +842,7 @@ handoffp(P *p)
        }
        // no local work, check that there are no spinning/idle M's,
        // otherwise our help is not required
-       if(runtime·sched.nmspinning + runtime·sched.npidle == 0 &&  // TODO: fast atomic
+       if(runtime·atomicload(&runtime·sched.nmspinning) + runtime·atomicload(&runtime·sched.npidle) == 0 &&  // TODO: fast atomic
                runtime·cas(&runtime·sched.nmspinning, 0, 1)) {
                startm(p, true);
                return;
@@ -996,7 +996,7 @@ top:
        // If number of spinning M's >= number of busy P's, block.
        // This is necessary to prevent excessive CPU consumption
        // when GOMAXPROCS>>1 but the program parallelism is low.
-       if(!m->spinning && 2 * runtime·sched.nmspinning >= runtime·gomaxprocs - runtime·sched.npidle)  // TODO: fast atomic
+       if(!m->spinning && 2 * runtime·atomicload(&runtime·sched.nmspinning) >= runtime·gomaxprocs - runtime·atomicload(&runtime·sched.npidle))  // TODO: fast atomic
                goto stop;
        if(!m->spinning) {
                m->spinning = true;
@@ -1079,8 +1079,8 @@ top:
        // M wakeup policy is deliberately somewhat conservative (see nmspinning handling),
        // so see if we need to wakeup another M here.
        if (m->p->runqhead != m->p->runqtail &&
-               runtime·sched.nmspinning == 0 &&
-               runtime·sched.npidle > 0)  // TODO: fast atomic
+               runtime·atomicload(&runtime·sched.nmspinning) == 0 &&
+               runtime·atomicload(&runtime·sched.npidle) > 0)  // TODO: fast atomic
                wakep();
 
        if(gp->lockedm) {
@@ -1197,10 +1197,10 @@ void
                runtime·throw("entersyscall");
        }
 
-       if(runtime·sched.sysmonwait) {  // TODO: fast atomic
+       if(runtime·atomicload(&runtime·sched.sysmonwait)) {  // TODO: fast atomic
                runtime·lock(&runtime·sched);
-               if(runtime·sched.sysmonwait) {
-                       runtime·sched.sysmonwait = false;
+               if(runtime·atomicload(&runtime·sched.sysmonwait)) {
+                       runtime·atomicstore(&runtime·sched.sysmonwait, 0);
                        runtime·notewakeup(&runtime·sched.sysmonnote);
                }
                runtime·unlock(&runtime·sched);
@@ -1457,7 +1457,7 @@ runtime·newproc1(FuncVal *fn, byte *argp, int32 narg, int32 nret, void *callerp
                newg->racectx = runtime·racegostart(callerpc);
        runqput(m->p, newg);
 
-       if(runtime·sched.npidle != 0 && runtime·sched.nmspinning == 0 && fn->fn != runtime·main)  // TODO: fast atomic
+       if(runtime·atomicload(&runtime·sched.npidle) != 0 && runtime·atomicload(&runtime·sched.nmspinning) == 0 && fn->fn != runtime·main)  // TODO: fast atomic
                wakep();
        return newg;
 }
@@ -1915,10 +1915,10 @@ sysmon(void)
                if(delay > 10*1000)  // up to 10ms
                        delay = 10*1000;
                runtime·usleep(delay);
-               if(runtime·gcwaiting || runtime·sched.npidle == runtime·gomaxprocs) {  // TODO: fast atomic
+               if(runtime·gcwaiting || runtime·atomicload(&runtime·sched.npidle) == runtime·gomaxprocs) {  // TODO: fast atomic
                        runtime·lock(&runtime·sched);
-                       if(runtime·gcwaiting || runtime·sched.npidle == runtime·gomaxprocs) {
-                               runtime·sched.sysmonwait = true;
+                       if(runtime·atomicload(&runtime·gcwaiting) || runtime·atomicload(&runtime·sched.npidle) == runtime·gomaxprocs) {
+                               runtime·atomicstore(&runtime·sched.sysmonwait, 1);
                                runtime·unlock(&runtime·sched);
                                runtime·notesleep(&runtime·sched.sysmonnote);
                                runtime·noteclear(&runtime·sched.sysmonnote);
@@ -1954,7 +1954,7 @@ retake(uint32 *ticks)
                s = p->status;
                if(s != Psyscall)
                        continue;
-               if(p->runqhead == p->runqtail && runtime·sched.nmspinning + runtime·sched.npidle > 0)  // TODO: fast atomic
+               if(p->runqhead == p->runqtail && runtime·atomicload(&runtime·sched.nmspinning) + runtime·atomicload(&runtime·sched.npidle) > 0)  // TODO: fast atomic
                        continue;
                // Need to increment number of locked M's before the CAS.
                // Otherwise the M from which we retake can exit the syscall,
@@ -2042,7 +2042,7 @@ pidleput(P *p)
 {
        p->link = runtime·sched.pidle;
        runtime·sched.pidle = p;
-       runtime·sched.npidle++;  // TODO: fast atomic
+       runtime·xadd(&runtime·sched.npidle, 1);  // TODO: fast atomic
 }
 
 // Try get a p from pidle list.
@@ -2055,7 +2055,7 @@ pidleget(void)
        p = runtime·sched.pidle;
        if(p) {
                runtime·sched.pidle = p->link;
-               runtime·sched.npidle--;  // TODO: fast atomic
+               runtime·xadd(&runtime·sched.npidle, -1);  // TODO: fast atomic
        }
        return p;
 }

diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index 602b185ad6b73bd366f33f81f3e0328a72175403..08f43a69b1eb1adacad14f4ef399461311bd2a72 100644 (file)
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -628,7 +628,7 @@ extern      P**     runtime·allp;
 extern int32   runtime·gomaxprocs;
 extern bool    runtime·singleproc;
 extern uint32  runtime·panicking;
-extern int32   runtime·gcwaiting;             // gc is waiting to run
+extern uint32  runtime·gcwaiting;             // gc is waiting to run
 extern int8*   runtime·goos;
 extern int32   runtime·ncpu;
 extern bool    runtime·iscgo;