- Split the run queue and sleep queue linkage, so that a process

may block on a mutex while on the sleep queue without corrupting
it.
- Move dropping of Giant to after the acquire of sched_lock.

Tested by:	John Hay <jhay@icomtek.csir.co.za>
		jhb

12 files changed, 22 insertions, 18 deletions

diff --git a/sys/alpha/alpha/trap.c b/sys/alpha/alpha/trap.c
index a387910..50a386d 100644
--- a/sys/alpha/alpha/trap.c
+++ b/sys/alpha/alpha/trap.c
@@ -120,8 +120,8 @@ userret(p, pc, oticks, have_giant)
 		 * indicated by our priority.
 		 */
 		s = splstatclock();
-		DROP_GIANT_NOSWITCH();
 		mtx_enter(&sched_lock, MTX_SPIN);
+		DROP_GIANT_NOSWITCH();
 		setrunqueue(p);
 		p->p_stats->p_ru.ru_nivcsw++;
 		mi_switch();
diff --git a/sys/amd64/amd64/trap.c b/sys/amd64/amd64/trap.c
index 21e5e12..fa768ec 100644
--- a/sys/amd64/amd64/trap.c
+++ b/sys/amd64/amd64/trap.c
@@ -192,8 +192,8 @@ userret(p, frame, oticks, have_giant)
 		 * our priority.
 		 */
 		s = splhigh();
-		DROP_GIANT_NOSWITCH();
 		mtx_enter(&sched_lock, MTX_SPIN);
+		DROP_GIANT_NOSWITCH();
 		setrunqueue(p);
 		p->p_stats->p_ru.ru_nivcsw++;
 		mi_switch();
diff --git a/sys/i386/i386/trap.c b/sys/i386/i386/trap.c
index 21e5e12..fa768ec 100644
--- a/sys/i386/i386/trap.c
+++ b/sys/i386/i386/trap.c
@@ -192,8 +192,8 @@ userret(p, frame, oticks, have_giant)
 		 * our priority.
 		 */
 		s = splhigh();
-		DROP_GIANT_NOSWITCH();
 		mtx_enter(&sched_lock, MTX_SPIN);
+		DROP_GIANT_NOSWITCH();
 		setrunqueue(p);
 		p->p_stats->p_ru.ru_nivcsw++;
 		mi_switch();
diff --git a/sys/ia64/ia64/trap.c b/sys/ia64/ia64/trap.c
index f519543..64f7752 100644
--- a/sys/ia64/ia64/trap.c
+++ b/sys/ia64/ia64/trap.c
@@ -102,8 +102,8 @@ userret(register struct proc *p, u_int64_t pc, u_quad_t oticks, int have_giant)
 		 * indicated by our priority.
 		 */
 		s = splstatclock();
-		DROP_GIANT_NOSWITCH();
 		mtx_enter(&sched_lock, MTX_SPIN);
+		DROP_GIANT_NOSWITCH();
 		setrunqueue(p);
 		p->p_stats->p_ru.ru_nivcsw++;
 		mi_switch();
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
index 354ff91..58a98d1 100644
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -718,6 +718,7 @@ static char *dup_list[] = {
 };
 
 static char *sleep_list[] = {
+	"Giant",
 	NULL
 };
 
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index dcc0ed3..a49964e 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1283,8 +1283,8 @@ issignal(p)
 			psignal(p->p_pptr, SIGCHLD);
 			do {
 				stop(p);
-				DROP_GIANT_NOSWITCH();
 				mtx_enter(&sched_lock, MTX_SPIN);
+				DROP_GIANT_NOSWITCH();
 				mi_switch();
 				mtx_exit(&sched_lock, MTX_SPIN);
 				PICKUP_GIANT();
@@ -1356,8 +1356,8 @@ issignal(p)
 				stop(p);
 				if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0)
 					psignal(p->p_pptr, SIGCHLD);
-				DROP_GIANT_NOSWITCH();
 				mtx_enter(&sched_lock, MTX_SPIN);
+				DROP_GIANT_NOSWITCH();
 				mi_switch();
 				mtx_exit(&sched_lock, MTX_SPIN);
 				PICKUP_GIANT();
diff --git a/sys/kern/kern_subr.c b/sys/kern/kern_subr.c
index 429f34b..c379f79 100644
--- a/sys/kern/kern_subr.c
+++ b/sys/kern/kern_subr.c
@@ -377,8 +377,8 @@ uio_yield()
 
 	p = curproc;
 	s = splhigh();
-	DROP_GIANT_NOSWITCH();
 	mtx_enter(&sched_lock, MTX_SPIN);
+	DROP_GIANT_NOSWITCH();
 	p->p_priority = p->p_usrpri;
 	setrunqueue(p);
 	p->p_stats->p_ru.ru_nivcsw++;
diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index 13b5707..972b682 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -420,9 +420,9 @@ msleep(ident, mtx, priority, wmesg, timo)
 	if (p && KTRPOINT(p, KTR_CSW))
 		ktrcsw(p->p_tracep, 1, 0);
 #endif
-	DROP_GIANT_NOSWITCH();
 	WITNESS_SLEEP(0, mtx);
 	mtx_enter(&sched_lock, MTX_SPIN);
+	DROP_GIANT_NOSWITCH();
 
 	if (mtx != NULL) {
 		mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED);
@@ -461,7 +461,7 @@ msleep(ident, mtx, priority, wmesg, timo)
 	p->p_nativepri = p->p_priority;
 	CTR4(KTR_PROC, "msleep: proc %p (pid %d, %s), schedlock %p",
 		p, p->p_pid, p->p_comm, (void *) sched_lock.mtx_lock);
-	TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_procq);
+	TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_slpq);
 	if (timo)
 		thandle = timeout(endtsleep, (void *)p, timo);
 	/*
@@ -583,7 +583,7 @@ asleep(void *ident, int priority, const char *wmesg, int timo)
 		p->p_slptime = 0;
 		p->p_asleep.as_priority = priority;
 		p->p_asleep.as_timo = timo;
-		TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_procq);
+		TAILQ_INSERT_TAIL(&slpque[LOOKUP(ident)], p, p_slpq);
 	}
 
 	mtx_exit(&sched_lock, MTX_SPIN);
@@ -612,9 +612,9 @@ mawait(struct mtx *mtx, int priority, int timo)
 	int s;
 	WITNESS_SAVE_DECL(mtx);
 
-	DROP_GIANT_NOSWITCH();
 	WITNESS_SLEEP(0, mtx);
 	mtx_enter(&sched_lock, MTX_SPIN);
+	DROP_GIANT_NOSWITCH();
 	if (mtx != NULL) {
 		mtx_assert(mtx, MA_OWNED | MA_NOTRECURSED);
 		WITNESS_SAVE(mtx, mtx);
@@ -778,7 +778,7 @@ unsleep(p)
 	s = splhigh();
 	mtx_enter(&sched_lock, MTX_SPIN);
 	if (p->p_wchan) {
-		TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_procq);
+		TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_slpq);
 		p->p_wchan = 0;
 	}
 	mtx_exit(&sched_lock, MTX_SPIN);
@@ -800,9 +800,9 @@ wakeup(ident)
 	mtx_enter(&sched_lock, MTX_SPIN);
 	qp = &slpque[LOOKUP(ident)];
 restart:
-	TAILQ_FOREACH(p, qp, p_procq) {
+	TAILQ_FOREACH(p, qp, p_slpq) {
 		if (p->p_wchan == ident) {
-			TAILQ_REMOVE(qp, p, p_procq);
+			TAILQ_REMOVE(qp, p, p_slpq);
 			p->p_wchan = 0;
 			if (p->p_stat == SSLEEP) {
 				/* OPTIMIZED EXPANSION OF setrunnable(p); */
@@ -846,9 +846,9 @@ wakeup_one(ident)
 	mtx_enter(&sched_lock, MTX_SPIN);
 	qp = &slpque[LOOKUP(ident)];
 
-	TAILQ_FOREACH(p, qp, p_procq) {
+	TAILQ_FOREACH(p, qp, p_slpq) {
 		if (p->p_wchan == ident) {
-			TAILQ_REMOVE(qp, p, p_procq);
+			TAILQ_REMOVE(qp, p, p_slpq);
 			p->p_wchan = 0;
 			if (p->p_stat == SSLEEP) {
 				/* OPTIMIZED EXPANSION OF setrunnable(p); */
diff --git a/sys/kern/subr_trap.c b/sys/kern/subr_trap.c
index 21e5e12..fa768ec 100644
--- a/sys/kern/subr_trap.c
+++ b/sys/kern/subr_trap.c
@@ -192,8 +192,8 @@ userret(p, frame, oticks, have_giant)
 		 * our priority.
 		 */
 		s = splhigh();
-		DROP_GIANT_NOSWITCH();
 		mtx_enter(&sched_lock, MTX_SPIN);
+		DROP_GIANT_NOSWITCH();
 		setrunqueue(p);
 		p->p_stats->p_ru.ru_nivcsw++;
 		mi_switch();
diff --git a/sys/kern/subr_turnstile.c b/sys/kern/subr_turnstile.c
index 354ff91..58a98d1 100644
--- a/sys/kern/subr_turnstile.c
+++ b/sys/kern/subr_turnstile.c
@@ -718,6 +718,7 @@ static char *dup_list[] = {
 };
 
 static char *sleep_list[] = {
+	"Giant",
 	NULL
 };
 
diff --git a/sys/kern/subr_witness.c b/sys/kern/subr_witness.c
index 354ff91..58a98d1 100644
--- a/sys/kern/subr_witness.c
+++ b/sys/kern/subr_witness.c
@@ -718,6 +718,7 @@ static char *dup_list[] = {
 };
 
 static char *sleep_list[] = {
+	"Giant",
 	NULL
 };
 
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index af24b30..6534f90 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -127,7 +127,8 @@ struct mtx;
 struct ithd;
 
 struct	proc {
-	TAILQ_ENTRY(proc) p_procq;	/* run/sleep queue. */
+	TAILQ_ENTRY(proc) p_procq;	/* run/mutex queue. */
+	TAILQ_ENTRY(proc) p_slpq;	/* sleep queue. */
 	LIST_ENTRY(proc) p_list;	/* List of all processes. */
 
 	/* substructures: */