From: Willy Tarreau <w@1wt.eu>
Date: Thu, 20 Jul 2023 13:25:57 +0000 (+0200)
Subject: MINOR: cpu-topo: add NUMA node identification to CPUs on Linux
X-Git-Tag: v3.2-dev8~80
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f6154c079e134c2e3ebc3da951d23d168e3522c8;p=thirdparty%2Fhaproxy.git

MINOR: cpu-topo: add NUMA node identification to CPUs on Linux

With this patch we're also assigning NUMA node IDs to each CPU when one
is found. The code is highly inspired from the one in commit b56a7c89a
("MEDIUM: cfgparse: detect numa and set affinity if needed") that already
did the job, except that it could be simplified since we're just collecting
info to fill the ha_cpu_topo[] array.
---

diff --git a/src/cpu_topo.c b/src/cpu_topo.c
index b1a131021..185f53505 100644
--- a/src/cpu_topo.c
+++ b/src/cpu_topo.c
@@ -1,5 +1,6 @@
 #define _GNU_SOURCE
 
+#include <dirent.h>
 #include <sched.h>
 #include <string.h>
 #include <unistd.h>
@@ -217,6 +218,9 @@ int cpu_detect_topology(void)
 {
 	const char *parse_cpu_set_args[2];
 	struct ha_cpu_topo cpu_id = { }; /* all zeroes */
+	struct hap_cpuset node_cpu_set;
+	struct dirent *de;
+	DIR *dir;
 	int cpu;
 
 	/* now let's only focus on bound CPUs to learn more about their
@@ -374,6 +378,42 @@ int cpu_detect_topology(void)
 				ha_cpu_topo[cpu].capa = str2uic(trash.area);
 		}
 	}
+
+	/* Now locate NUMA node IDs if any */
+
+	dir = opendir(NUMA_DETECT_SYSTEM_SYSFS_PATH "/node");
+	if (dir) {
+		while ((de = readdir(dir))) {
+			long node_id;
+			char *endptr;
+
+			/* dir name must start with "node" prefix */
+			if (strncmp(de->d_name, "node", 4) != 0)
+				continue;
+
+			/* dir name must be at least 5 characters long */
+			if (!de->d_name[4])
+				continue;
+
+			/* dir name must end with a non-negative numeric id */
+			node_id = strtol(&de->d_name[4], &endptr, 10);
+			if (*endptr || node_id < 0)
+				continue;
+
+			/* all tests succeeded, it's in the form "node%d" */
+			if (read_line_to_trash("%s/node/%s/cpulist", NUMA_DETECT_SYSTEM_SYSFS_PATH, de->d_name) >= 0) {
+				parse_cpu_set_args[0] = trash.area;
+				parse_cpu_set_args[1] = "\0";
+				if (parse_cpu_set(parse_cpu_set_args, &node_cpu_set, NULL) == 0) {
+					for (cpu = 0; cpu < cpu_topo_maxcpus; cpu++)
+						if (ha_cpuset_isset(&node_cpu_set, cpu))
+							ha_cpu_topo[cpu].no_id = node_id;
+				}
+			}
+		}
+		/* done */
+		closedir(dir);
+	}
 	return 1;
 }