From ebe98ffcc2517fa7e0a251914c52274e8a378b1c Mon Sep 17 00:00:00 2001
From: Sandipan Das <sandipan.das@amd.com>
Date: Fri, 27 Jun 2025 15:47:59 +0530
Subject: [PATCH 4/6] common: Resolve max count of CPUs at runtime

Replace statically defined NCPUS_MAX with a variable which is set at
runtime. Use libnuma helpers to determine the OS-defined limits for the
maximum possible number of CPUs in the the system.

Signed-off-by: Sandipan Das <sandipan.das@amd.com>
---
 common/include/types.h |  2 +-
 common/numatop.c       |  2 +-
 common/os/node.c       |  2 ++
 common/os/os_util.c    | 16 ++++++++++------
 4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/common/include/types.h b/common/include/types.h
index e688225..eb64fb1 100644
--- a/common/include/types.h
+++ b/common/include/types.h
@@ -116,12 +116,12 @@ typedef enum {
 #define UI_COUNT_NUM		5
 
 #define NCPUS_NODE_MAX		256
-#define	NCPUS_MAX		(nnodes_max * NCPUS_NODE_MAX)
 #define NPROCS_NAX		4096
 #define	LL_THRESH		128
 #define LL_PERIOD		1000
 
 extern int nnodes_max;
+extern int ncpus_max;
 
 typedef struct _count_value {
 	uint64_t counts[PERF_COUNT_NUM];
diff --git a/common/numatop.c b/common/numatop.c
index c5c0580..2e95378 100644
--- a/common/numatop.c
+++ b/common/numatop.c
@@ -236,7 +236,7 @@ main(int argc, char *argv[])
 	if (node_group_init() != 0) {
 		stderr_print("The node/cpu number is out of range, \n"
 		    "numatop supports up to %d nodes and %d CPUs\n",
-		    nnodes_max, NCPUS_MAX);
+		    nnodes_max, ncpus_max);
 		goto L_EXIT5;
 	}
 
diff --git a/common/os/node.c b/common/os/node.c
index c2ca7a7..f79bcdf 100644
--- a/common/os/node.c
+++ b/common/os/node.c
@@ -48,6 +48,7 @@ static node_group_t s_node_group;
 int g_ncpus;
 
 int nnodes_max;
+int ncpus_max;
 
 static void
 node_init(node_t *node, int nid, boolean_t hotadd)
@@ -86,6 +87,7 @@ node_group_init(void)
 		return (-1);
 
 	nnodes_max = numa_num_possible_nodes();
+	ncpus_max = numa_num_possible_cpus();
 
 	(void) memset(&s_node_group, 0, sizeof (node_group_t));
 	if (pthread_mutex_init(&s_node_group.mutex, NULL) != 0) {
diff --git a/common/os/os_util.c b/common/os/os_util.c
index ec3f6e5..c836e89 100644
--- a/common/os/os_util.c
+++ b/common/os/os_util.c
@@ -470,19 +470,23 @@ os_sysfs_cpu_enum(int nid, int *cpu_arr, int arr_size, int *num)
 int
 os_sysfs_online_ncpus(void)
 {
-	int cpu_arr[NCPUS_MAX], num;
+	int *cpu_arr, num, ret = -1;
 	char path[PATH_MAX];
 
-	if (sysconf(_SC_NPROCESSORS_CONF) > NCPUS_MAX) {
+	cpu_arr = (int *) malloc(ncpus_max * sizeof(int));
+	if (!cpu_arr)
 		return (-1);
-	}
 
 	snprintf(path, PATH_MAX, "/sys/devices/system/cpu/online");
-	if (!file_int_extract(path, cpu_arr, NCPUS_MAX, &num)) {
-		return (-1);
+	if (!file_int_extract(path, cpu_arr, ncpus_max, &num)) {
+		goto L_EXIT;
 	}
 
-	return (num);
+	ret = num;
+
+L_EXIT:
+	free(cpu_arr);
+	return (ret);
 }
 
 static boolean_t
-- 
2.49.0