From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@techsingularity.net>,
Rik van Riel <riel@surriel.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 09/19] sched/numa: Modify migrate_swap to accept additional params
Date: Mon, 4 Jun 2018 15:30:18 +0530 [thread overview]
Message-ID: <1528106428-19992-10-git-send-email-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1528106428-19992-1-git-send-email-srikar@linux.vnet.ibm.com>
There are checks in migrate_swap_stop that check if the task/cpu
combination is as per migrate_swap_arg before migrating.
However atleast one of the two tasks to be swapped by migrate_swap could
have migrated to a completely different cpu before updating the
migrate_swap_arg. The new cpu where the task is currently running could
be a different node too. If the task has migrated, numa balancer might
end up placing a task in a wrong node. Instead of achieving node
consolidation, it may end up spreading the load across nodes.
To avoid that pass the cpus as additional parameters.
While here, place migrate_swap under CONFIG_NUMA_BALANCING.
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
kernel/sched/core.c | 9 ++++++---
kernel/sched/fair.c | 3 ++-
kernel/sched/sched.h | 3 ++-
3 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 092f7c4..68849c2 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1178,6 +1178,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
__set_task_cpu(p, new_cpu);
}
+#ifdef CONFIG_NUMA_BALANCING
static void __migrate_swap_task(struct task_struct *p, int cpu)
{
if (task_on_rq_queued(p)) {
@@ -1259,16 +1260,17 @@ static int migrate_swap_stop(void *data)
/*
* Cross migrate two tasks
*/
-int migrate_swap(struct task_struct *cur, struct task_struct *p)
+int migrate_swap(struct task_struct *cur, struct task_struct *p,
+ int target_cpu, int curr_cpu)
{
struct migration_swap_arg arg;
int ret = -EINVAL;
arg = (struct migration_swap_arg){
.src_task = cur,
- .src_cpu = task_cpu(cur),
+ .src_cpu = curr_cpu,
.dst_task = p,
- .dst_cpu = task_cpu(p),
+ .dst_cpu = target_cpu,
};
if (arg.src_cpu == arg.dst_cpu)
@@ -1293,6 +1295,7 @@ int migrate_swap(struct task_struct *cur, struct task_struct *p)
out:
return ret;
}
+#endif /* CONFIG_NUMA_BALANCING */
/*
* wait_task_inactive - wait for a thread to unschedule.
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 35c4a75..46d773c 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1810,7 +1810,8 @@ static int task_numa_migrate(struct task_struct *p)
return ret;
}
- ret = migrate_swap(p, env.best_task);
+ ret = migrate_swap(p, env.best_task, env.best_cpu, env.src_cpu);
+
if (ret != 0)
trace_sched_stick_numa(p, env.src_cpu, task_cpu(env.best_task));
put_task_struct(env.best_task);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 15750c2..211841e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1068,7 +1068,8 @@ enum numa_faults_stats {
};
extern void sched_setnuma(struct task_struct *p, int node);
extern int migrate_task_to(struct task_struct *p, int cpu);
-extern int migrate_swap(struct task_struct *, struct task_struct *);
+extern int migrate_swap(struct task_struct *p, struct task_struct *t,
+ int cpu, int scpu);
#endif /* CONFIG_NUMA_BALANCING */
#ifdef CONFIG_SMP
--
1.8.3.1
next prev parent reply other threads:[~2018-06-04 10:01 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 10:00 [PATCH 00/19] Fixes for sched/numa_balancing Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 01/19] sched/numa: Remove redundant field Srikar Dronamraju
2018-06-04 14:53 ` Rik van Riel
2018-06-05 8:41 ` Mel Gorman
2018-06-04 10:00 ` [PATCH 02/19] sched/numa: Evaluate move once per node Srikar Dronamraju
2018-06-04 14:51 ` Rik van Riel
2018-06-04 15:45 ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 03/19] sched/numa: Simplify load_too_imbalanced Srikar Dronamraju
2018-06-04 14:57 ` Rik van Riel
2018-06-05 8:46 ` Mel Gorman
2018-06-04 10:00 ` [PATCH 04/19] sched/numa: Set preferred_node based on best_cpu Srikar Dronamraju
2018-06-04 12:18 ` Peter Zijlstra
2018-06-04 12:53 ` Srikar Dronamraju
2018-06-04 12:23 ` Peter Zijlstra
2018-06-04 12:59 ` Srikar Dronamraju
2018-06-04 13:39 ` Peter Zijlstra
2018-06-04 13:48 ` Srikar Dronamraju
2018-06-04 14:37 ` Rik van Riel
2018-06-04 15:56 ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 05/19] sched/numa: Use task faults only if numa_group is not yet setup Srikar Dronamraju
2018-06-04 12:24 ` Peter Zijlstra
2018-06-04 13:09 ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 06/19] sched/debug: Reverse the order of printing faults Srikar Dronamraju
2018-06-04 16:28 ` Rik van Riel
2018-06-05 8:50 ` Mel Gorman
2018-06-04 10:00 ` [PATCH 07/19] sched/numa: Skip nodes that are at hoplimit Srikar Dronamraju
2018-06-04 16:27 ` Rik van Riel
2018-06-05 8:50 ` Mel Gorman
2018-06-04 10:00 ` [PATCH 08/19] sched/numa: Remove unused task_capacity from numa_stats Srikar Dronamraju
2018-06-04 16:28 ` Rik van Riel
2018-06-05 8:57 ` Mel Gorman
2018-06-04 10:00 ` Srikar Dronamraju [this message]
2018-06-04 17:00 ` [PATCH 09/19] sched/numa: Modify migrate_swap to accept additional params Rik van Riel
2018-06-05 8:58 ` Mel Gorman
2018-06-04 10:00 ` [PATCH 10/19] sched/numa: Stop multiple tasks from moving to the cpu at the same time Srikar Dronamraju
2018-06-04 17:57 ` Rik van Riel
2018-06-05 9:51 ` Mel Gorman
2018-06-04 10:00 ` [PATCH 11/19] sched/numa: Restrict migrating in parallel to the same node Srikar Dronamraju
2018-06-04 17:59 ` Rik van Riel
2018-06-05 9:53 ` Mel Gorman
2018-06-06 12:58 ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 12/19] sched:numa Remove numa_has_capacity Srikar Dronamraju
2018-06-04 18:07 ` Rik van Riel
2018-06-04 10:00 ` [PATCH 13/19] mm/migrate: Use xchg instead of spinlock Srikar Dronamraju
2018-06-04 18:22 ` Rik van Riel
2018-06-04 19:28 ` Peter Zijlstra
2018-06-05 7:24 ` Srikar Dronamraju
2018-06-05 8:16 ` Peter Zijlstra
2018-06-04 10:00 ` [PATCH 14/19] sched/numa: Updation of scan period need not be in lock Srikar Dronamraju
2018-06-04 18:24 ` Rik van Riel
2018-06-04 10:00 ` [PATCH 15/19] sched/numa: Use group_weights to identify if migration degrades locality Srikar Dronamraju
2018-06-04 18:56 ` Rik van Riel
2018-06-04 10:00 ` [PATCH 16/19] sched/numa: Detect if node actively handling migration Srikar Dronamraju
2018-06-04 20:05 ` Rik van Riel
2018-06-05 3:56 ` Srikar Dronamraju
2018-06-05 13:07 ` Rik van Riel
2018-06-06 12:55 ` Srikar Dronamraju
2018-06-06 13:55 ` Rik van Riel
2018-06-06 15:32 ` Srikar Dronamraju
2018-06-06 17:06 ` Rik van Riel
2018-06-04 10:00 ` [PATCH 17/19] sched/numa: Pass destination cpu as a parameter to migrate_task_rq Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 18/19] sched/numa: Reset scan rate whenever task moves across nodes Srikar Dronamraju
2018-06-04 20:08 ` Rik van Riel
2018-06-05 9:58 ` Mel Gorman
2018-06-06 13:47 ` Srikar Dronamraju
2018-06-04 10:00 ` [PATCH 19/19] sched/numa: Move task_placement closer to numa_migrate_preferred Srikar Dronamraju
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