sched/numa: Remove the redundant member numa_group::fault_cpus

numa_group::fault_cpus is actually a pointer to the region
in numa_group::faults[] where NUMA_CPU stats are located.

Remove this redundant member and use numa_group::faults[NUMA_CPU]
directly like it is done for similar per-process numa fault stats.

There is no functionality change due to this commit.

Signed-off-by: Bharata B Rao <bharata@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Link: https://lkml.kernel.org/r/20211004105706.3669-3-bharata@amd.com

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index fc0a0ed63d152953c5f17ea105252fda89b94e39..cfbd5ef0b558c1cf33e5386e9894f764eb3c2778 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1038,11 +1038,12 @@ struct numa_group {
        unsigned long total_faults;
        unsigned long max_faults_cpu;
        /*
+        * faults[] array is split into two regions: faults_mem and faults_cpu.
+        *
         * Faults_cpu is used to decide whether memory should move
         * towards the CPU. As a consequence, these stats are weighted
         * more by CPU use than by memory faults.
         */
-       unsigned long *faults_cpu;
        unsigned long faults[];
 };
 
@@ -1216,8 +1217,8 @@ static inline unsigned long group_faults(struct task_struct *p, int nid)
 
 static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
 {
-       return group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 0)] +
-               group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 1)];
+       return group->faults[task_faults_idx(NUMA_CPU, nid, 0)] +
+               group->faults[task_faults_idx(NUMA_CPU, nid, 1)];
 }
 
 static inline unsigned long group_faults_priv(struct numa_group *ng)
@@ -2384,7 +2385,7 @@ static void task_numa_placement(struct task_struct *p)
                                 * is at the beginning of the numa_faults array.
                                 */
                                ng->faults[mem_idx] += diff;
-                               ng->faults_cpu[mem_idx] += f_diff;
+                               ng->faults[cpu_idx] += f_diff;
                                ng->total_faults += diff;
                                group_faults += ng->faults[mem_idx];
                        }
@@ -2450,9 +2451,6 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
                grp->max_faults_cpu = 0;
                spin_lock_init(&grp->lock);
                grp->gid = p->pid;
-               /* Second half of the array tracks nids where faults happen */
-               grp->faults_cpu = grp->faults + NR_NUMA_HINT_FAULT_TYPES *
-                                               nr_node_ids;
 
                for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
                        grp->faults[i] = p->numa_faults[i];