PERFORCE change 131741 for review

[John Birrell]

http://perforce.freebsd.org/chv.cgi?CH=131741

Change 131741 by jb at jb_freebsd1 on 2007/12/26 23:42:52

	Add support to rendezvous calls to specific CPUs.
	
	Sun uses an xcall facility in OpenSolaris. This is our equivalent.

Affected files ...

.. //depot/projects/dtrace/src/sys/kern/subr_smp.c#7 edit
.. //depot/projects/dtrace/src/sys/sys/smp.h#5 edit

Differences ...

==== //depot/projects/dtrace/src/sys/kern/subr_smp.c#7 (text+ko) ====

@@ -104,6 +104,7 @@
 	   "Forwarding of roundrobin to all other CPUs");
 
 /* Variables needed for SMP rendezvous. */
+static volatile cpumask_t smp_rv_cpumask;
 static void (*volatile smp_rv_setup_func)(void *arg);
 static void (*volatile smp_rv_action_func)(void *arg);
 static void (* volatile smp_rv_teardown_func)(void *arg);
@@ -305,14 +306,20 @@
 void
 smp_rendezvous_action(void)
 {
+	cpumask_t map = smp_rv_cpumask;
+	int i, ncpus = 0;
 	void* local_func_arg = smp_rv_func_arg;
 	void (*local_setup_func)(void*)   = smp_rv_setup_func;
 	void (*local_action_func)(void*)   = smp_rv_action_func;
 	void (*local_teardown_func)(void*) = smp_rv_teardown_func;
+
+	for (i = 0; i < MAXCPU; i++)
+		if (((1 << i) & map) != 0 && pcpu_find(i) != NULL)
+			ncpus++;
  
 	/* Ensure we have up-to-date values. */
 	atomic_add_acq_int(&smp_rv_waiters[0], 1);
-	while (smp_rv_waiters[0] < mp_ncpus)
+	while (smp_rv_waiters[0] < ncpus)
 		cpu_spinwait();
 
 	/* setup function */
@@ -321,7 +328,7 @@
 			smp_rv_setup_func(smp_rv_func_arg);
 		/* spin on entry rendezvous */
 		atomic_add_int(&smp_rv_waiters[1], 1);
-		while (smp_rv_waiters[1] < mp_ncpus)
+		while (smp_rv_waiters[1] < ncpus)
                 	cpu_spinwait();
 	}
 
@@ -335,7 +342,7 @@
 	atomic_add_int(&smp_rv_waiters[2], 1);
 	if (local_teardown_func == smp_no_rendevous_barrier)
                 return;
-	while (smp_rv_waiters[2] < mp_ncpus)
+	while (smp_rv_waiters[2] < ncpus)
 		cpu_spinwait();
 	/* teardown function */
 	if (local_teardown_func != NULL)
@@ -343,11 +350,13 @@
 }
 
 void
-smp_rendezvous(void (* setup_func)(void *), 
-	       void (* action_func)(void *),
-	       void (* teardown_func)(void *),
-	       void *arg)
+smp_rendezvous_cpus(cpumask_t map,
+	void (* setup_func)(void *), 
+	void (* action_func)(void *),
+	void (* teardown_func)(void *),
+	void *arg)
 {
+	int i, ncpus = 0;
 
 	if (!smp_started) {
 		if (setup_func != NULL)
@@ -358,11 +367,16 @@
 			teardown_func(arg);
 		return;
 	}
+
+	for (i = 0; i < MAXCPU; i++)
+		if (((1 << i) & map) != 0 && pcpu_find(i) != NULL)
+			ncpus++;
 		
 	/* obtain rendezvous lock */
 	mtx_lock_spin(&smp_ipi_mtx);
 
 	/* set static function pointers */
+	smp_rv_cpumask = map & ~(1 << curcpu);
 	smp_rv_setup_func = setup_func;
 	smp_rv_action_func = action_func;
 	smp_rv_teardown_func = teardown_func;
@@ -371,21 +385,30 @@
 	smp_rv_waiters[2] = 0;
 	atomic_store_rel_int(&smp_rv_waiters[0], 0);
 
-		
-
 	/* signal other processors, which will enter the IPI with interrupts off */
-	ipi_all_but_self(IPI_RENDEZVOUS);
+	ipi_selected(map, IPI_RENDEZVOUS);
 
-	/* call executor function */
-	smp_rendezvous_action();
+	/* Check if the current CPU is in the map */
+	if ((map & (1 << curcpu)) != 0)
+		/* call executor function for the current CPU */
+		smp_rendezvous_action();
 
 	if (teardown_func == smp_no_rendevous_barrier) { 
-		while (atomic_load_acq_int(&smp_rv_waiters[2]) < mp_ncpus)
+		while (atomic_load_acq_int(&smp_rv_waiters[2]) < ncpus)
 			cpu_spinwait();
 	}
 	/* release lock */
 	mtx_unlock_spin(&smp_ipi_mtx);
 }
+
+void
+smp_rendezvous(void (* setup_func)(void *), 
+	       void (* action_func)(void *),
+	       void (* teardown_func)(void *),
+	       void *arg)
+{
+	smp_rendezvous_cpus(all_cpus, setup_func, action_func, teardown_func, arg);
+}
 #else /* !SMP */
 
 /*
@@ -404,6 +427,21 @@
     mp_setvariables_for_up, NULL)
 
 void
+smp_rendezvous_cpus(cpumask_t map,
+	void (* setup_func)(void *), 
+	void (* action_func)(void *),
+	void (* teardown_func)(void *),
+	void *arg)
+{
+	if (setup_func != NULL)
+		setup_func(arg);
+	if (action_func != NULL)
+		action_func(arg);
+	if (teardown_func != NULL)
+		teardown_func(arg);
+}
+
+void
 smp_rendezvous(void (* setup_func)(void *), 
 	       void (* action_func)(void *),
 	       void (* teardown_func)(void *),

==== //depot/projects/dtrace/src/sys/sys/smp.h#5 (text+ko) ====

@@ -108,6 +108,11 @@
 		       void (*)(void *),
 		       void (*)(void *),
 		       void *arg);
+void	smp_rendezvous_cpus(cpumask_t,
+		       void (*)(void *), 
+		       void (*)(void *),
+		       void (*)(void *),
+		       void *arg);
 #endif /* !LOCORE */
 #endif /* _KERNEL */
 #endif /* _SYS_SMP_H_ */