[PATCH v3 1/2] perf bench numa: use numa_node_to_cpus() to bind tasks to nodes

[Alexander Gordeev]

It is currently assumed that each node contains at most
nr_cpus/nr_nodes CPUs and nodes' CPU ranges do not overlap.
That assumption is generally incorrect as there are archs
where a CPU number does not depend on to its node number.

This update removes the described assumption by simply calling
numa_node_to_cpus() interface and using the returned mask for
binding CPUs to nodes.

Also, variable types and names made consistent in functions
using cpumask.

Cc: Satheesh Rajendran <sathn...@linux.vnet.ibm.com>
Cc: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
Cc: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
Cc: Balamuruhan S <bal...@linux.vnet.ibm.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Arnaldo Carvalho de Melo <a...@kernel.org>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Alexander Shishkin <alexander.shish...@linux.intel.com>
Cc: Jiri Olsa <jo...@redhat.com>
Cc: Namhyung Kim <namhy...@kernel.org>
Signed-off-by: Alexander Gordeev <agord...@linux.ibm.com>
---
 tools/perf/bench/numa.c | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index 9066511..6d5c890 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -247,20 +247,20 @@ static int is_node_present(int node)
  */
 static bool node_has_cpus(int node)
 {
-       struct bitmask *cpu = numa_allocate_cpumask();
+       struct bitmask *cpumask = numa_allocate_cpumask();
        bool ret = false; /* fall back to nocpus */
-       unsigned int i;
+       int cpu;
 
-       BUG_ON(!cpu);
-       if (!numa_node_to_cpus(node, cpu)) {
-               for (i = 0; i < cpu->size; i++) {
-                       if (numa_bitmask_isbitset(cpu, i)) {
+       BUG_ON(!cpumask);
+       if (!numa_node_to_cpus(node, cpumask)) {
+               for (cpu = 0; cpu < (int)cpumask->size; cpu++) {
+                       if (numa_bitmask_isbitset(cpumask, cpu)) {
                                ret = true;
                                break;
                        }
                }
        }
-       numa_free_cpumask(cpu);
+       numa_free_cpumask(cpumask);
 
        return ret;
 }
@@ -293,14 +293,10 @@ static cpu_set_t bind_to_cpu(int target_cpu)
 
 static cpu_set_t bind_to_node(int target_node)
 {
-       int cpus_per_node = g->p.nr_cpus / nr_numa_nodes();
        cpu_set_t orig_mask, mask;
        int cpu;
        int ret;
 
-       BUG_ON(cpus_per_node * nr_numa_nodes() != g->p.nr_cpus);
-       BUG_ON(!cpus_per_node);
-
        ret = sched_getaffinity(0, sizeof(orig_mask), &orig_mask);
        BUG_ON(ret);
 
@@ -310,13 +306,16 @@ static cpu_set_t bind_to_node(int target_node)
                for (cpu = 0; cpu < g->p.nr_cpus; cpu++)
                        CPU_SET(cpu, &mask);
        } else {
-               int cpu_start = (target_node + 0) * cpus_per_node;
-               int cpu_stop  = (target_node + 1) * cpus_per_node;
-
-               BUG_ON(cpu_stop > g->p.nr_cpus);
+               struct bitmask *cpumask = numa_allocate_cpumask();
 
-               for (cpu = cpu_start; cpu < cpu_stop; cpu++)
-                       CPU_SET(cpu, &mask);
+               BUG_ON(!cpumask);
+               if (!numa_node_to_cpus(target_node, cpumask)) {
+                       for (cpu = 0; cpu < (int)cpumask->size; cpu++) {
+                               if (numa_bitmask_isbitset(cpumask, cpu))
+                                       CPU_SET(cpu, &mask);
+                       }
+               }
+               numa_free_cpumask(cpumask);
        }
 
        ret = sched_setaffinity(0, sizeof(mask), &mask);
-- 
1.8.3.1