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From: Steve Sistare <steven.sistare@oracle.com>
To: mingo@redhat.com, peterz@infradead.org
Cc: subhra.mazumdar@oracle.com, dhaval.giani@oracle.com,
	daniel.m.jordan@oracle.com, pavel.tatashin@microsoft.com,
	matt@codeblueprint.co.uk, umgwanakikbuti@gmail.com,
	riel@redhat.com, jbacik@fb.com, juri.lelli@redhat.com,
	valentin.schneider@arm.com, vincent.guittot@linaro.org,
	quentin.perret@arm.com, steven.sistare@oracle.com,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3 07/10] sched/fair: Provide can_migrate_task_llc
Date: Fri,  9 Nov 2018 04:50:37 -0800	[thread overview]
Message-ID: <1541767840-93588-8-git-send-email-steven.sistare@oracle.com> (raw)
In-Reply-To: <1541767840-93588-1-git-send-email-steven.sistare@oracle.com>

Define a simpler version of can_migrate_task called can_migrate_task_llc
which does not require a struct lb_env argument, and judges whether a
migration from one CPU to another within the same LLC should be allowed.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 kernel/sched/fair.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 453d280..dc6224d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7199,6 +7199,34 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
 }
 
 /*
+ * Return true if task @p can migrate from @rq to @dst_rq in the same LLC.
+ * No need to test for co-locality, and no need to test task_hot(), as sharing
+ * LLC provides cache warmth at that level.
+ */
+static bool
+can_migrate_task_llc(struct task_struct *p, struct rq *rq, struct rq *dst_rq)
+{
+	int dst_cpu = dst_rq->cpu;
+
+	lockdep_assert_held(&rq->lock);
+
+	if (throttled_lb_pair(task_group(p), cpu_of(rq), dst_cpu))
+		return false;
+
+	if (!cpumask_test_cpu(dst_cpu, &p->cpus_allowed)) {
+		schedstat_inc(p->se.statistics.nr_failed_migrations_affine);
+		return false;
+	}
+
+	if (task_running(rq, p)) {
+		schedstat_inc(p->se.statistics.nr_failed_migrations_running);
+		return false;
+	}
+
+	return true;
+}
+
+/*
  * detach_task() -- detach the task for the migration from @src_rq to @dst_cpu.
  */
 static void detach_task(struct task_struct *p, struct rq *src_rq, int dst_cpu)
-- 
1.8.3.1


  parent reply	other threads:[~2018-11-09 13:01 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-09 12:50 [PATCH v3 00/10] steal tasks to improve CPU utilization Steve Sistare
2018-11-09 12:50 ` [PATCH v3 01/10] sched: Provide sparsemask, a reduced contention bitmap Steve Sistare
2018-11-27 15:16   ` Steven Sistare
2018-11-28  1:19     ` Omar Sandoval
2018-12-06 16:07       ` Steven Sistare
2018-12-06 18:19         ` Omar Sandoval
2018-11-09 12:50 ` [PATCH v3 02/10] sched/topology: Provide hooks to allocate data shared per LLC Steve Sistare
2018-11-09 12:50 ` [PATCH v3 03/10] sched/topology: Provide cfs_overload_cpus bitmap Steve Sistare
2018-11-09 17:38   ` Valentin Schneider
2018-11-19 17:32     ` Steven Sistare
2018-11-20 12:52       ` Valentin Schneider
2018-11-12 16:42   ` Valentin Schneider
2018-11-19 17:33     ` Steven Sistare
2018-11-20 12:42       ` Valentin Schneider
2018-11-26 19:06         ` Steven Sistare
2018-12-03 16:56           ` Valentin Schneider
2018-12-06 16:40             ` Steven Sistare
2018-12-06 17:28               ` Valentin Schneider
2018-11-09 12:50 ` [PATCH v3 04/10] sched/fair: Dynamically update cfs_overload_cpus Steve Sistare
2018-11-09 12:50 ` [PATCH v3 05/10] sched/fair: Hoist idle_stamp up from idle_balance Steve Sistare
2018-11-09 19:07   ` Valentin Schneider
2018-11-19 17:31     ` Steven Sistare
2018-11-20 10:24       ` Valentin Schneider
2018-11-09 12:50 ` [PATCH v3 06/10] sched/fair: Generalize the detach_task interface Steve Sistare
2018-11-09 12:50 ` Steve Sistare [this message]
2018-11-09 12:50 ` [PATCH v3 08/10] sched/fair: Steal work from an overloaded CPU when CPU goes idle Steve Sistare
2018-11-09 12:50 ` [PATCH v3 09/10] sched/fair: disable stealing if too many NUMA nodes Steve Sistare
2018-11-09 12:50 ` [PATCH v3 10/10] sched/fair: Provide idle search schedstats Steve Sistare
2018-11-10 17:08   ` kbuild test robot
2018-11-09 15:02 ` hackbench run scripts Steven Sistare

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