perf tools: Add numa_topology object

Add the numa_topology object to return the list of numa nodes together
with their cpus. It will replace the numa code in header.c and will be
used from 'perf record' in the following patches.

Add the following interface functions to load numa details:

  struct numa_topology *numa_topology__new(void);
  void numa_topology__delete(struct numa_topology *tp);

And replace the current (copied) local interface, with no functional
changes.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190219095815.15931-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/cputopo.c

@@ -1,9 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <sys/param.h>
+#include <inttypes.h>
 
 #include "cputopo.h"
 #include "cpumap.h"
 #include "util.h"
+#include "env.h"
 
 
 #define CORE_SIB_FMT \
@@ -142,3 +144,119 @@ out_free:
 	}
 	return tp;
 }
+
+static int load_numa_node(struct numa_topology_node *node, int nr)
+{
+	char str[MAXPATHLEN];
+	char field[32];
+	char *buf = NULL, *p;
+	size_t len = 0;
+	int ret = -1;
+	FILE *fp;
+	u64 mem;
+
+	node->node = (u32) nr;
+
+	sprintf(str, "/sys/devices/system/node/node%d/meminfo", nr);
+	fp = fopen(str, "r");
+	if (!fp)
+		return -1;
+
+	while (getline(&buf, &len, fp) > 0) {
+		/* skip over invalid lines */
+		if (!strchr(buf, ':'))
+			continue;
+		if (sscanf(buf, "%*s %*d %31s %"PRIu64, field, &mem) != 2)
+			goto err;
+		if (!strcmp(field, "MemTotal:"))
+			node->mem_total = mem;
+		if (!strcmp(field, "MemFree:"))
+			node->mem_free = mem;
+		if (node->mem_total && node->mem_free)
+			break;
+	}
+
+	fclose(fp);
+	fp = NULL;
+
+	sprintf(str, "/sys/devices/system/node/node%d/cpulist", nr);
+
+	fp = fopen(str, "r");
+	if (!fp)
+		return -1;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto err;
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	node->cpus = buf;
+	fclose(fp);
+	return 0;
+
+err:
+	free(buf);
+	if (fp)
+		fclose(fp);
+	return ret;
+}
+
+struct numa_topology *numa_topology__new(void)
+{
+	struct cpu_map *node_map = NULL;
+	struct numa_topology *tp = NULL;
+	char *buf = NULL;
+	size_t len = 0;
+	u32 nr, i;
+	FILE *fp;
+	char *c;
+
+	fp = fopen("/sys/devices/system/node/online", "r");
+	if (!fp)
+		return NULL;
+
+	if (getline(&buf, &len, fp) <= 0)
+		goto out;
+
+	c = strchr(buf, '\n');
+	if (c)
+		*c = '\0';
+
+	node_map = cpu_map__new(buf);
+	if (!node_map)
+		goto out;
+
+	nr = (u32) node_map->nr;
+
+	tp = zalloc(sizeof(*tp) + sizeof(tp->nodes[0])*nr);
+	if (!tp)
+		goto out;
+
+	tp->nr = nr;
+
+	for (i = 0; i < nr; i++) {
+		if (load_numa_node(&tp->nodes[i], node_map->map[i])) {
+			numa_topology__delete(tp);
+			tp = NULL;
+			break;
+		}
+	}
+
+out:
+	free(buf);
+	fclose(fp);
+	cpu_map__put(node_map);
+	return tp;
+}
+
+void numa_topology__delete(struct numa_topology *tp)
+{
+	u32 i;
+
+	for (i = 0; i < tp->nr; i++)
+		free(tp->nodes[i].cpus);
+
+	free(tp);
+}