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From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org
Subject: [PATCH 3/4] sched: WARN when migrating to an offline CPU
Date: Thu, 07 Sep 2017 17:03:52 +0200
Message-ID: <20170907150614.094206976@infradead.org> (raw)
In-Reply-To: <20170907150349.063852465@infradead.org>


[-- Attachment #0: peterz-sched-warn-migrate-to-offline.patch --]
[-- Type: text/plain, Size: 608 bytes --]

Migrating tasks to offline CPUs is a pretty big fail, warn about it.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 kernel/sched/core.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1173,6 +1173,10 @@ void set_task_cpu(struct task_struct *p,
 	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
 				      lockdep_is_held(&task_rq(p)->lock)));
 #endif
+	/*
+	 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
+	 */
+	WARN_ON_ONCE(!cpu_online(new_cpu));
 #endif
 
 	trace_sched_migrate_task(p, new_cpu);

  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-07 15:03 [PATCH 0/4] sched: Fix some load-balancer vs hotplug holes Peter Zijlstra
2017-09-07 15:03 ` [PATCH 1/4] sched/fair: Avoid newidle balance for !active CPUs Peter Zijlstra
2017-09-12 18:04   ` [tip:sched/urgent] " tip-bot for Peter Zijlstra
2017-09-07 15:03 ` [PATCH 2/4] sched/fair: Plug hole between hotplug and active load_balance Peter Zijlstra
2017-09-12 18:05   ` [tip:sched/urgent] sched/fair: Plug hole between hotplug and active_load_balance() tip-bot for Peter Zijlstra
2017-09-07 15:03 ` Peter Zijlstra [this message]
2017-09-12 18:05   ` [tip:sched/urgent] sched/core: WARN() when migrating to an offline CPU tip-bot for Peter Zijlstra
2017-09-28  9:14   ` [PATCH 3/4] sched: WARN " Sasha Levin
2017-09-28 10:35     ` Peter Zijlstra
2017-09-28 11:03       ` Levin, Alexander (Sasha Levin)
2017-09-28 11:42         ` Peter Zijlstra
2017-09-29 11:11           ` Peter Zijlstra
2017-10-07  2:07             ` Levin, Alexander (Sasha Levin)
2017-10-07  9:15               ` Peter Zijlstra
     [not found]                 ` <20171007174327.ky6g5viokxg5ysdm@sasha-lappy>
2017-10-09  8:04                   ` Peter Zijlstra
2017-10-10  1:18                     ` Levin, Alexander (Sasha Levin)
2017-09-07 15:03 ` [PATCH 4/4] sched/debug: Add debugfs knob for "sched_debug" Peter Zijlstra
2017-09-12 18:05   ` [tip:sched/urgent] " tip-bot for Peter Zijlstra

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