[PATCH v4 7/9] lib/group_cpus: honor housekeeping config when grouping CPUs

[Daniel Wagner <wagi@xxxxxxxxxx>]

group_cpus_evenly distributes all present CPUs into groups. This ignores
the isolcpus configuration and assigns isolated CPUs into the groups.

Make group_cpus_evenly aware of isolcpus configuration and use the
housekeeping CPU mask as base for distributing the available CPUs into
groups.

Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Signed-off-by: Daniel Wagner <wagi@xxxxxxxxxx>
---
 lib/group_cpus.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 75 insertions(+), 2 deletions(-)

diff --git a/lib/group_cpus.c b/lib/group_cpus.c
index 73da83ca2c45347a3a443d42d4f16801a47effd5..927e4ed634d0d9ca14235c977fc53d6f5f649396 100644
--- a/lib/group_cpus.c
+++ b/lib/group_cpus.c
@@ -8,6 +8,7 @@
 #include <linux/cpu.h>
 #include <linux/sort.h>
 #include <linux/group_cpus.h>
+#include <linux/sched/isolation.h>
 
 #ifdef CONFIG_SMP
 
@@ -330,7 +331,7 @@ static int __group_cpus_evenly(unsigned int startgrp, unsigned int numgrps,
 }
 
 /**
- * group_cpus_evenly - Group all CPUs evenly per NUMA/CPU locality
+ * group_possible_cpus_evenly - Group all CPUs evenly per NUMA/CPU locality
  * @numgrps: number of groups
  *
  * Return: cpumask array if successful, NULL otherwise. And each element
@@ -345,7 +346,7 @@ static int __group_cpus_evenly(unsigned int startgrp, unsigned int numgrps,
  * We guarantee in the resulted grouping that all CPUs are covered, and
  * no same CPU is assigned to multiple groups
  */
-struct cpumask *group_cpus_evenly(unsigned int *numgrps)
+static struct cpumask *group_possible_cpus_evenly(unsigned int *numgrps)
 {
 	unsigned int curgrp = 0, nr_present = 0, nr_others = 0, nr_grps;
 	cpumask_var_t *node_to_cpumask;
@@ -426,6 +427,78 @@ struct cpumask *group_cpus_evenly(unsigned int *numgrps)
 	*numgrps = nr_present + nr_others;
 	return masks;
 }
+
+/**
+ * group_mask_cpus_evenly - Group all CPUs evenly per NUMA/CPU locality
+ * @numgrps: number of groups
+ * @cpu_mask: CPU to consider for the grouping
+ *
+ * Return: cpumask array if successful, NULL otherwise. And each element
+ * includes CPUs assigned to this group.
+ *
+ * Try to put close CPUs from viewpoint of CPU and NUMA locality into
+ * same group. Allocate present CPUs on these groups evenly.
+ */
+static struct cpumask *group_mask_cpus_evenly(unsigned int *numgrps,
+					      const struct cpumask *cpu_mask)
+{
+	cpumask_var_t *node_to_cpumask;
+	cpumask_var_t nmsk;
+	unsigned int nr_grps;
+	int ret = -ENOMEM;
+	struct cpumask *masks = NULL;
+
+	if (!zalloc_cpumask_var(&nmsk, GFP_KERNEL))
+		return NULL;
+
+	node_to_cpumask = alloc_node_to_cpumask();
+	if (!node_to_cpumask)
+		goto fail_nmsk;
+
+	nr_grps = *numgrps;
+	masks = kcalloc(nr_grps, sizeof(*masks), GFP_KERNEL);
+	if (!masks)
+		goto fail_node_to_cpumask;
+
+	build_node_to_cpumask(node_to_cpumask);
+
+	ret = __group_cpus_evenly(0, nr_grps, node_to_cpumask, cpu_mask, nmsk,
+				  masks);
+
+fail_node_to_cpumask:
+	free_node_to_cpumask(node_to_cpumask);
+
+fail_nmsk:
+	free_cpumask_var(nmsk);
+	if (ret < 0) {
+		kfree(masks);
+		return NULL;
+	}
+	*numgrps = ret;
+	return masks;
+}
+
+/**
+ * group_cpus_evenly - Group all CPUs evenly per NUMA/CPU locality
+ * @numgrps: number of groups
+ *
+ * Return: cpumask array if successful, NULL otherwise.
+ *
+ * group_possible_cpus_evently() is used for distributing the cpus on all
+ * possible cpus in absence of isolcpus command line argument.
+ * group_mask_cpu_evenly() is used when the isolcpus command line
+ * argument is used with managed_irq option. In this case only the
+ * housekeeping CPUs are considered.
+ */
+struct cpumask *group_cpus_evenly(unsigned int *numgrps)
+{
+	if (housekeeping_enabled(HK_TYPE_MANAGED_IRQ)) {
+		return group_mask_cpus_evenly(numgrps,
+				housekeeping_cpumask(HK_TYPE_MANAGED_IRQ));
+	}
+
+	return group_possible_cpus_evenly(numgrps);
+}
 #else /* CONFIG_SMP */
 struct cpumask *group_cpus_evenly(unsigned int *numgrps)
 {

-- 
2.47.1