runtime: remove nomemprof

Nomemprof seems to be unneeded now, there is no recursion.
If the recursion will be re-introduced, it will break loudly by deadlocking.
Fixes #6566.

R=golang-dev, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/14695044

src/pkg/runtime/mprof.goc

@@ -255,10 +255,6 @@ runtime·MProf_Malloc(void *p, uintptr size)
 	uintptr stk[32];
 	Bucket *b;
 
-	if(m->nomemprof > 0)
-		return;
-
-	m->nomemprof++;
 	nstk = runtime·callers(1, stk, 32);
 	runtime·lock(&proflock);
 	b = stkbucket(MProf, stk, nstk, true);
@@ -266,7 +262,6 @@ runtime·MProf_Malloc(void *p, uintptr size)
 	b->recent_alloc_bytes += size;
 	setaddrbucket((uintptr)p, b);
 	runtime·unlock(&proflock);
-	m->nomemprof--;
 }
 
 // Called when freeing a profiled block.
@@ -275,10 +270,6 @@ runtime·MProf_Free(void *p, uintptr size)
 {
 	Bucket *b;
 
-	if(m->nomemprof > 0)
-		return;
-
-	m->nomemprof++;
 	runtime·lock(&proflock);
 	b = getaddrbucket((uintptr)p);
 	if(b != nil) {
@@ -286,7 +277,6 @@ runtime·MProf_Free(void *p, uintptr size)
 		b->recent_free_bytes += size;
 	}
 	runtime·unlock(&proflock);
-	m->nomemprof--;
 }
 
 int64 runtime·blockprofilerate;  // in CPU ticks

src/pkg/runtime/proc.c

@@ -133,7 +133,6 @@ runtime·schedinit(void)
 	runtime·sched.maxmcount = 10000;
 	runtime·precisestack = haveexperiment("precisestack");
 
-	m->nomemprof++;
 	runtime·mprofinit();
 	runtime·mallocinit();
 	mcommoninit(m);
@@ -163,7 +162,6 @@ runtime·schedinit(void)
 	procresize(procs);
 
 	mstats.enablegc = 1;
-	m->nomemprof--;
 
 	if(raceenabled)
 		g->racectx = runtime·raceinit();

src/pkg/runtime/runtime.h

@@ -310,7 +310,6 @@ struct	M
 	int32	throwing;
 	int32	gcing;
 	int32	locks;
-	int32	nomemprof;
 	int32	dying;
 	int32	profilehz;
 	int32	helpgc;