sched/numa: Report a NUMA task group ID

It is desirable to model from userspace how the scheduler groups tasks
over time. This patch adds an ID to the numa_group and reports it via
/proc/PID/status.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-45-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 85565053a6ed..5bd309c035c7 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -893,12 +893,18 @@ struct numa_group {
 
         spinlock_t lock; /* nr_tasks, tasks */
         int nr_tasks;
+        pid_t gid;
         struct list_head task_list;
 
         struct rcu_head rcu;
         atomic_long_t faults[0];
 };
 
+pid_t task_numa_group_id(struct task_struct *p)
+{
+        return p->numa_group ? p->numa_group->gid : 0;
+}
+
 static inline int task_faults_idx(int nid, int priv)
 {
         return 2 * nid + priv;
@@ -1265,6 +1271,7 @@ static void task_numa_group(struct task_struct *p, int cpupid)
                 atomic_set(&grp->refcount, 1);
                 spin_lock_init(&grp->lock);
                 INIT_LIST_HEAD(&grp->task_list);
+                grp->gid = p->pid;
 
                 for (i = 0; i < 2*nr_node_ids; i++)
                         atomic_long_set(&grp->faults[i], p->numa_faults[i]);