From: Tomas Hruby <tom@minix3.org>
Date: Wed, 15 Sep 2010 14:10:51 +0000 (+0000)
Subject: SMP - Balancing run queues for SMP
X-Git-Tag: v3.2.0~850
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/zlib_tech.html?a=commitdiff_plain;h=311f145bc7d570f5baabcd168d9872f7efedd4f0;p=minix.git

SMP - Balancing run queues for SMP

- it preempts running processes though :( this is not the final
  solution
---

diff --git a/kernel/system.c b/kernel/system.c
index 6e02000da..14454009e 100644
--- a/kernel/system.c
+++ b/kernel/system.c
@@ -662,11 +662,14 @@ PUBLIC int sched_proc(struct proc *p,
 
 	/* FIXME this is a problem for SMP if the processes currently runs on a
 	 * different CPU */
-	if (proc_is_runnable(p) && p->p_cpu != cpuid &&
-			(cpu != -1 || cpu != p->p_cpu)) {
-		printf("WARNING : changing cpu of a runnable process %d "
-				"on a different cpu!\n", p->p_endpoint);
-		return(EINVAL);
+	if (proc_is_runnable(p)) {
+		if (p->p_cpu != cpuid && cpu != -1 && cpu != p->p_cpu) {
+			printf("WARNING : changing cpu of a runnable process %d "
+					"on a different cpu!\n", p->p_endpoint);
+			return(EINVAL);
+		}
+
+		RTS_SET(p, RTS_NO_QUANTUM);
 	}
 
 	if (proc_is_runnable(p))
diff --git a/servers/sched/schedule.c b/servers/sched/schedule.c
index 97e9674f9..4e1e24ca3 100644
--- a/servers/sched/schedule.c
+++ b/servers/sched/schedule.c
@@ -19,9 +19,25 @@ PRIVATE unsigned balance_timeout;
 
 #define BALANCE_TIMEOUT	5 /* how often to balance queues in seconds */
 
-FORWARD _PROTOTYPE( int schedule_process, (struct schedproc * rmp)	);
+FORWARD _PROTOTYPE( int schedule_process, (struct schedproc * rmp,
+			unsigned flags));
 FORWARD _PROTOTYPE( void balance_queues, (struct timer *tp)		);
 
+#define SCHEDULE_CHANGE_PRIO	0x1
+#define SCHEDULE_CHANGE_QUANTUM	0x2
+#define SCHEDULE_CHANGE_CPU	0x4
+
+#define SCHEDULE_CHANGE_ALL	(	\
+		SCHEDULE_CHANGE_PRIO	|	\
+		SCHEDULE_CHANGE_QUANTUM	|	\
+		SCHEDULE_CHANGE_CPU		\
+		)
+
+#define schedule_process_local(p)	\
+	schedule_process(p, SCHEDULE_CHANGE_PRIO | SCHEDULE_CHANGE_QUANTUM)
+#define schedule_process_migrate(p)	\
+	schedule_process(p, SCHEDULE_CHANGE_CPU)
+
 #define DEFAULT_USER_TIME_SLICE 200
 
 /* processes created by RS are sysytem processes */
@@ -79,7 +95,7 @@ PUBLIC int do_noquantum(message *m_ptr)
 		rmp->priority += 1; /* lower priority */
 	}
 
-	if ((rv = schedule_process(rmp)) != OK) {
+	if ((rv = schedule_process_local(rmp)) != OK) {
 		return rv;
 	}
 	return OK;
@@ -197,7 +213,8 @@ PUBLIC int do_start_scheduling(message *m_ptr)
 	rmp->flags = IN_USE;
 
 	/* Schedule the process, giving it some quantum */
-	if ((rv = schedule_process(rmp)) != OK) {
+	pick_cpu(rmp);
+	if ((rv = schedule_process(rmp, SCHEDULE_CHANGE_ALL)) != OK) {
 		printf("Sched: Error while scheduling process, kernel replied %d\n",
 			rv);
 		return rv;
@@ -248,7 +265,7 @@ PUBLIC int do_nice(message *m_ptr)
 	/* Update the proc entry and reschedule the process */
 	rmp->max_priority = rmp->priority = new_q;
 
-	if ((rv = schedule_process(rmp)) != OK) {
+	if ((rv = schedule_process_local(rmp)) != OK) {
 		/* Something went wrong when rescheduling the process, roll
 		 * back the changes to proc struct */
 		rmp->priority     = old_q;
@@ -261,19 +278,35 @@ PUBLIC int do_nice(message *m_ptr)
 /*===========================================================================*
  *				schedule_process			     *
  *===========================================================================*/
-PRIVATE int schedule_process(struct schedproc * rmp)
+PRIVATE int schedule_process(struct schedproc * rmp, unsigned flags)
 {
-	int rv;
+	int err;
+	int new_prio, new_quantum, new_cpu;
 
 	pick_cpu(rmp);
 
-	if ((rv = sys_schedule(rmp->endpoint, rmp->priority,
-			rmp->time_slice, rmp->cpu)) != OK) {
-		printf("SCHED: An error occurred when trying to schedule %d: %d\n",
-		rmp->endpoint, rv);
+	if (flags & SCHEDULE_CHANGE_PRIO)
+		new_prio = rmp->priority;
+	else
+		new_prio = -1;
+
+	if (flags & SCHEDULE_CHANGE_QUANTUM)
+		new_quantum = rmp->time_slice;
+	else
+		new_quantum = -1;
+
+	if (flags & SCHEDULE_CHANGE_CPU)
+		new_cpu = rmp->cpu;
+	else
+		new_cpu = -1;
+
+	if ((err = sys_schedule(rmp->endpoint, new_prio,
+		new_quantum, new_cpu)) != OK) {
+		printf("PM: An error occurred when trying to schedule %d: %d\n",
+		rmp->endpoint, err);
 	}
 
-	return rv;
+	return err;
 }
 
 
@@ -307,7 +340,7 @@ PRIVATE void balance_queues(struct timer *tp)
 		if (rmp->flags & IN_USE) {
 			if (rmp->priority > rmp->max_priority) {
 				rmp->priority -= 1; /* increase priority */
-				schedule_process(rmp);
+				schedule_process_local(rmp);
 			}
 		}
 	}