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sched/numa: Trace when no candidate CPU was found on the preferred node

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sched:sched_stick_numa is meant to fire when a task is unable to migrate
to the preferred node. The case where no candidate CPU could be found is
not traced which is an important gap. The tracepoint is not fired when
the task is not allowed to run on any CPU on the preferred node or the
task is already running on the target CPU but neither are interesting
corner cases.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Link: https://lore.kernel.org/r/20200224095223.13361-3-mgorman@techsingularity.net
This commit is contained in:
Mel Gorman 2020-02-24 09:52:12 +00:00 committed by Ingo Molnar
parent 546121b65f
commit f22aef4afb
1 changed files with 3 additions and 1 deletions
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4
kernel/sched/fair.c
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@ -1848,8 +1848,10 @@ static int task_numa_migrate(struct task_struct *p)
}
/* No better CPU than the current one was found. */
if (env.best_cpu == -1)
if (env.best_cpu == -1) {
trace_sched_stick_numa(p, env.src_cpu, -1);
return -EAGAIN;
}
best_rq = cpu_rq(env.best_cpu);
if (env.best_task == NULL) {