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Commit db015dae authored by Rik van Riel's avatar Rik van Riel Committed by Ingo Molnar
Browse files

sched/numa: Rework best node setting in task_numa_migrate() 



Fix up the best node setting in task_numa_migrate() to deal with a task
in a pseudo-interleaved NUMA group, which is already running in the
best location.

Set the task's preferred nid to the current nid, so task migration is
not retried at a high rate.

Signed-off-by: default avatarRik van Riel <riel@redhat.com>
Cc: mgorman@suse.de
Cc: chegu_vinod@hp.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1403538095-31256-7-git-send-email-riel@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 0132c3e1

kernel/sched/fair.c

+13 −6
Original line number Diff line number Diff line
@@ -1354,10 +1354,6 @@ static int task_numa_migrate(struct task_struct *p) 
		}

	}



	/* No better CPU than the current one was found. */

	if (env.best_cpu == -1)

		return -EAGAIN;



	/*

	 * If the task is part of a workload that spans multiple NUMA nodes,

	 * and is migrating into one of the workload's active nodes, remember
@@ -1366,8 +1362,19 @@ static int task_numa_migrate(struct task_struct *p) 
	 * A task that migrated to a second choice node will be better off

	 * trying for a better one later. Do not set the preferred node here.

	 */

	if (p->numa_group && node_isset(env.dst_nid, p->numa_group->active_nodes))

	if (p->numa_group) {

		if (env.best_cpu == -1)

			nid = env.src_nid;

		else

			nid = env.dst_nid;



		if (node_isset(nid, p->numa_group->active_nodes))

			sched_setnuma(p, env.dst_nid);

	}



	/* No better CPU than the current one was found. */

	if (env.best_cpu == -1)

		return -EAGAIN;



	/*

	 * Reset the scan period if the task is being rescheduled on an