linux-kernel - [PATCH 1/2] perf/bench/numa: Add functions to detect sparse numa nodes

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Date:   Thu, 10 Aug 2017 12:58:49 +0530
From:   sathnaga@...ux.vnet.ibm.com
To:     acme@...nel.org, mingo@...nel.org, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org
Cc:     srikar@...ux.vnet.ibm.com, bala24@...ux.vnet.ibm.com,
        Satheesh Rajendran <sathnaga@...ux.vnet.ibm.com>
Subject: [PATCH 1/2] perf/bench/numa: Add functions to detect sparse numa nodes

From: Satheesh Rajendran <sathnaga@...ux.vnet.ibm.com>

Added functions 1) to get a count of all nodes that are exposed to
userspace. These nodes could be memoryless cpu nodes or cpuless memory
nodes, 2) to check given node is present and 3) to check given
node has cpus

This information can be used to handle sparse/discontiguous nodes.

Reviewed-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Signed-off-by: Satheesh Rajendran <sathnaga@...ux.vnet.ibm.com>
Signed-off-by: Balamuruhan S <bala24@...ux.vnet.ibm.com>
---
 tools/perf/bench/numa.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index 469d65b..efd7595 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -215,6 +215,41 @@ static const char * const numa_usage[] = {
 	NULL
 };
 
+static int nr_numa_nodes(void)
+{
+	int node = 0, i;
+
+        for (i = 0; i < g->p.nr_nodes; i++) {
+		if (numa_bitmask_isbitset(numa_nodes_ptr, i))
+			node++;
+	}
+	return node;
+}
+
+static bool is_node_present(int node)
+{
+	if (numa_bitmask_isbitset(numa_nodes_ptr, node))
+		return true;
+	else
+		return false;
+}
+
+static bool is_node_hascpu(int node)
+{
+	struct bitmask *cpu;
+	unsigned int i;
+
+	cpu = numa_allocate_cpumask();
+	if (numa_node_to_cpus(node, cpu) == 0) {
+		for (i = 0; i < cpu->size; i++) {
+			if (numa_bitmask_isbitset(cpu, i))
+				return true;
+			}
+	} else
+		return false; // lets fall back to nocpus safely
+	return false;
+}
+
 static cpu_set_t bind_to_cpu(int target_cpu)
 {
 	cpu_set_t orig_mask, mask;
-- 
2.7.4