sched/numa: Retry migration of tasks to CPU on a preferred node

When a preferred node is selected for a tasks there is an attempt to migrate
the task to a CPU there. This may fail in which case the task will only
migrate if the active load balancer takes action. This may never happen if
the conditions are not right. This patch will check at NUMA hinting fault
time if another attempt should be made to migrate the task. It will only
make an attempt once every five seconds.

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/1381141781-10992-34-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index d946195eec10..14251a8ff2ea 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1341,6 +1341,7 @@ struct task_struct {
         int numa_migrate_seq;
         unsigned int numa_scan_period;
         unsigned int numa_scan_period_max;
+        unsigned long numa_migrate_retry;
         u64 node_stamp;                 /* migration stamp  */
         struct callback_head numa_work;