top: Use a cpuset_t to represent a CPU mask

The code attempts to detect holes in the CPU ID space, but previously this would only work for up to sizeof(long)*8 CPUs. MFC after: 2 weeks
nhuff · May 26, 2023 · e96ed17 · e96ed17
1 parent 14c5cf3
commit e96ed17
Showing 1 changed file with 9 additions and 10 deletions.
diff --git a/usr.bin/top/machine.c b/usr.bin/top/machine.c
@@ -16,9 +16,10 @@
  * $FreeBSD$
  */
 
+#include <sys/param.h>
+#include <sys/cpuset.h>
 #include <sys/errno.h>
 #include <sys/fcntl.h>
-#include <sys/param.h>
 #include <sys/priority.h>
 #include <sys/proc.h>
 #include <sys/resource.h>
@@ -204,7 +205,7 @@ static const char *ordernames[] = {
 static int maxcpu;
 static int maxid;
 static int ncpus;
-static unsigned long cpumask;
+static cpuset_t cpumask;
 static long *times;
 static long *pcpu_cp_time;
 static long *pcpu_cp_old;
@@ -347,8 +348,6 @@ machine_init(struct statics *statics)
 	statics->order_names = ordernames;
 
 	/* Allocate state for per-CPU stats. */
-	cpumask = 0;
-	ncpus = 0;
 	GETSYSCTL("kern.smp.maxcpus", maxcpu);
 	times = calloc(maxcpu * CPUSTATES, sizeof(long));
 	if (times == NULL)
@@ -357,18 +356,18 @@ machine_init(struct statics *statics)
 	if (sysctlbyname("kern.cp_times", times, &size, NULL, 0) == -1)
 		err(1, "sysctlbyname kern.cp_times");
 	pcpu_cp_time = calloc(1, size);
-	maxid = (size / CPUSTATES / sizeof(long)) - 1;
+	maxid = MIN(size / CPUSTATES / sizeof(long) - 1, CPU_SETSIZE - 1);
+	CPU_ZERO(&cpumask);
 	for (i = 0; i <= maxid; i++) {
 		empty = 1;
 		for (j = 0; empty && j < CPUSTATES; j++) {
 			if (times[i * CPUSTATES + j] != 0)
 				empty = 0;
 		}
-		if (!empty) {
-			cpumask |= (1ul << i);
-			ncpus++;
-		}
+		if (!empty)
+			CPU_SET(i, &cpumask);
 	}
+	ncpus = CPU_COUNT(&cpumask);
 	assert(ncpus > 0);
 	pcpu_cp_old = calloc(ncpus * CPUSTATES, sizeof(long));
 	pcpu_cp_diff = calloc(ncpus * CPUSTATES, sizeof(long));
@@ -466,7 +465,7 @@ get_system_info(struct system_info *si)
 
 	/* convert cp_time counts to percentages */
 	for (i = j = 0; i <= maxid; i++) {
-		if ((cpumask & (1ul << i)) == 0)
+		if (!CPU_ISSET(i, &cpumask))
 			continue;
 		percentages(CPUSTATES, &pcpu_cpu_states[j * CPUSTATES],
 		    &pcpu_cp_time[j * CPUSTATES],