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From: Valentin Schneider <valentin.schneider@arm.com>
To: "Zengtao (B)" <prime.zeng@hisilicon.com>,
	Sudeep Holla <sudeep.holla@arm.com>
Cc: Linuxarm <linuxarm@huawei.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>
Subject: Re: [PATCH] cpu-topology: warn if NUMA configurations conflicts with lower layer
Date: Fri, 3 Jan 2020 12:14:35 +0000	[thread overview]
Message-ID: <66943c82-2cfd-351b-7f36-5aefdb196a03@arm.com> (raw)
In-Reply-To: <7b375d79-2d3c-422b-27a6-68972fbcbeaf@arm.com>

On 03/01/2020 10:57, Valentin Schneider wrote:
> I'm juggling with other things atm, but let me have a think and see if we
> couldn't detect that in the scheduler itself.
> 

Something like this ought to catch your case; might need to compare group
spans rather than pure group pointers.

---
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 6ec1e595b1d4..c4151e11afcd 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1120,6 +1120,13 @@ build_sched_groups(struct sched_domain *sd, int cpu)
 
 		sg = get_group(i, sdd);
 
+		/* sg's are inited as self-looping. If 'last' is not self
+		 * looping, we set it in a previous visit. No further visit
+		 * should change the link order, if we do then the topology
+		 * description is terminally broken.
+		 */
+		BUG_ON(last && last->next != last && last->next != sg);
+
 		cpumask_or(covered, covered, sched_group_span(sg));
 
 		if (!first)

  reply	other threads:[~2020-01-03 12:14 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-23  8:16 [PATCH] cpu-topology: warn if NUMA configurations conflicts with lower layer z00214469
2019-12-31 16:40 ` Sudeep Holla
2020-01-02  3:05   ` Zengtao (B)
2020-01-02 11:29     ` Sudeep Holla
2020-01-02 12:47       ` Zengtao (B)
2020-01-02 13:22         ` Valentin Schneider
2020-01-02 19:30           ` Dietmar Eggemann
2020-01-03  4:24           ` Zengtao (B)
2020-01-03 10:57             ` Valentin Schneider
2020-01-03 12:14               ` Valentin Schneider [this message]
2020-01-03 17:20                 ` Dietmar Eggemann
2020-01-06  1:48                   ` Zengtao (B)
2020-01-06 14:31                     ` Dietmar Eggemann
2020-01-08  2:19                       ` Zengtao (B)
2020-01-09 11:05                       ` Morten Rasmussen
2020-01-09 12:07                         ` Dietmar Eggemann
2020-01-06  1:52                 ` Zengtao (B)
2020-01-03 11:40             ` Sudeep Holla
2020-01-06  1:37               ` Zengtao (B)
2020-01-09 10:43                 ` Morten Rasmussen
2020-01-09 12:58                   ` Zengtao (B)
2020-01-11 20:56                     ` Valentin Schneider
2020-01-13  6:51                       ` Zengtao (B)
2020-01-13 11:16                         ` Valentin Schneider
2020-01-13 12:08                           ` Zengtao (B)
2020-01-13 12:22                             ` Dietmar Eggemann
2020-01-13 14:49                       ` Dietmar Eggemann
2020-01-13 15:15                         ` Valentin Schneider
2020-01-09 10:52           ` Morten Rasmussen
2020-01-12 13:22             ` Valentin Schneider
2020-01-13 13:22               ` Morten Rasmussen
2020-01-02 13:59         ` Sudeep Holla

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