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From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Olaf Hering <olaf@aepfle.de>
Cc: david.vrabel@citrix.com, jgross@suse.com,
	xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] xen/gntdev: Use mempolicy instead of VM_IO flag to avoid NUMA balancing
Date: Thu, 17 Nov 2016 11:01:15 -0500	[thread overview]
Message-ID: <af47b58b-82bc-164f-4874-2ac16f969e76@oracle.com> (raw)
In-Reply-To: <20161117112843.GA19761@aepfle.de>


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On 11/17/2016 06:28 AM, Olaf Hering wrote:
> On Wed, Nov 16, Boris Ostrovsky wrote:
>
>> Unfortunately I haven't been able to trigger NUMA balancing
>> so while I tested this in general I am not sure I actually
>> exercised the code path.
> Thanks for the patch!
>
> Would be nice to actually test the code path which caused the initial
> addition of VM_IO. I think I lack the hardware to excersise them.

To trip the original bug is even more difficult than to trigger NUMA
balancing. It was very sensitive to memory allocation.

>
>
> In my 4.4 based sources I get the following unresolved symbols. If that
> happens to work in mainline the failures should at least be considered
> during backporting of this proposed patch to the stable trees.
>
> ERROR: "__mpol_dup" [drivers/xen/xen-gntdev.ko] undefined!
> ERROR: "get_task_policy" [drivers/xen/xen-gntdev.ko] undefined!
>
> Appearently these symbols lack just an EXPORT_SYMBOL_GPL.


I just built 4.4.11 with this patch applied and haven't had any problems.

-boris


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  reply	other threads:[~2016-11-17 17:27 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-16 17:46 [PATCH v2] xen/gntdev: Use mempolicy instead of VM_IO flag to avoid NUMA balancing Boris Ostrovsky
2016-11-17 11:28 ` Olaf Hering
2016-11-17 16:01   ` Boris Ostrovsky [this message]
2016-11-17 16:01     ` Olaf Hering
2016-11-17 16:09       ` Boris Ostrovsky

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