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From: Mel Gorman <mgorman@suse.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, tglx@linutronix.de,
	linux-kernel@vger.kernel.org, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, paulmck@kernel.org,
	frederic@kernel.org
Subject: Re: [PATCH 1/6] sched: Fix ttwu_queue_cond()
Date: Mon, 22 Jun 2020 10:11:22 +0100	[thread overview]
Message-ID: <20200622091122.GG3129@suse.de> (raw)
In-Reply-To: <20200615131143.130326165@infradead.org>

On Mon, Jun 15, 2020 at 02:56:55PM +0200, Peter Zijlstra wrote:
> Where the condition:
> 
>   !cpus_share_cache(smp_processor_id(), cpu)
> 
> already implies 'cpu != smp_processor_id()', because a CPU always
> shares cache with itself, the secondary condition added in commit:
> 
>   2ebb17717550 ("sched/core: Offload wakee task activation if it the wakee is descheduling")
> 
> voids that implication, resulting in attempting to do local wake-ups
> through the queue mechanism.
> 
> Fixes: 2ebb17717550 ("sched/core: Offload wakee task activation if it the wakee is descheduling")
> Reported-by: Paul E. McKenney <paulmck@kernel.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Tested-by: Paul E. McKenney <paulmck@kernel.org>

Yep, I mistakenly though this would be covered by the self-wakeup check
early in try_to_wake_up() but it is not

Acked-by: Mel Gorman <mgorman@suse.de>

-- 
Mel Gorman
SUSE Labs

  parent reply	other threads:[~2020-06-22  9:11 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15 12:56 [PATCH 0/6] sched: TTWU, IPI, and assorted stuff Peter Zijlstra
2020-06-15 12:56 ` [PATCH 1/6] sched: Fix ttwu_queue_cond() Peter Zijlstra
2020-06-15 13:34   ` Peter Zijlstra
2020-06-15 16:45     ` Paul E. McKenney
2020-06-15 22:58       ` Paul E. McKenney
2020-06-22  9:11   ` Mel Gorman [this message]
2020-06-22  9:41     ` Peter Zijlstra
2020-06-15 12:56 ` [PATCH 2/6] sched: Verify some SMP assumptions Peter Zijlstra
2020-06-15 12:56 ` [PATCH 3/6] sched: s/WF_ON_RQ/WQ_ON_CPU/ Peter Zijlstra
2020-06-22  9:13   ` Mel Gorman
2020-06-15 12:56 ` [PATCH 4/6] smp, irq_work: Continue smp_call_function*() and irq_work*() integration Peter Zijlstra
2020-06-15 12:56 ` [PATCH 5/6] irq_work: Cleanup Peter Zijlstra
2020-06-16 15:16   ` Petr Mladek
2020-06-15 12:57 ` [PATCH 6/6] smp: Cleanup smp_call_function*() Peter Zijlstra
2020-06-15 14:34   ` Jens Axboe
2020-06-15 16:04   ` Daniel Thompson
2020-06-17  8:23   ` Christoph Hellwig
2020-06-17  9:00     ` Peter Zijlstra
2020-06-17 11:04     ` Peter Zijlstra
2020-06-18  6:51       ` Christoph Hellwig
2020-06-18 16:25         ` Peter Zijlstra
2020-06-15 16:23 ` [PATCH 0/6] sched: TTWU, IPI, and assorted stuff Paul E. McKenney
2020-06-15 16:40   ` Peter Zijlstra
2020-06-15 17:21     ` Paul E. McKenney
2020-06-15 19:11       ` Peter Zijlstra
2020-06-15 19:55         ` Paul E. McKenney
2020-06-16 16:31           ` Paul E. McKenney
2020-06-16 17:04         ` Peter Zijlstra
2020-06-16 17:17           ` Peter Zijlstra
2020-06-16 17:53             ` Paul E. McKenney
2020-06-19 13:44             ` Peter Zijlstra
2020-06-19 17:20               ` Paul E. McKenney
2020-06-19 17:48                 ` Paul E. McKenney
2020-06-19 18:11                   ` Peter Zijlstra
2020-06-19 18:46                     ` Paul E. McKenney
2020-06-20 18:46               ` Paul E. McKenney
2020-06-16 17:51           ` Paul E. McKenney

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