linux-kernel - Re: [PATCH v2] xen: xen-pciback: Remove create

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Date:	Tue, 28 Jun 2016 22:16:20 +0530
From:	Bhaktipriya Shridhar <bhaktipriya96@...il.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	Boris Ostrovsky <boris.ostrovsky@...cle.com>,
	David Vrabel <david.vrabel@...rix.com>,
	Juergen Gross <jgross@...e.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Jan Beulich <JBeulich@...e.com>,
	Stefano Stabellini <stefano.stabellini@...citrix.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Doug Goldstein <cardoe@...doe.com>,
	xen-devel@...ts.xenproject.org,
	"Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] xen: xen-pciback: Remove create_workqueue

Ping!
Thanks,
Bhaktipriya


On Wed, Jun 1, 2016 at 9:15 PM, Tejun Heo <tj@...nel.org> wrote:
> On Wed, Jun 01, 2016 at 07:45:08PM +0530, Bhaktipriya Shridhar wrote:
>> System workqueues have been able to handle high level of concurrency
>> for a long time now and there's no reason to use dedicated workqueues
>> just to gain concurrency.  Replace dedicated xen_pcibk_wq with the
>> use of system_wq.
>>
>> Unlike a dedicated per-cpu workqueue created with create_workqueue(),
>> system_wq allows multiple work items to overlap executions even on
>> the same CPU; however, a per-cpu workqueue doesn't have any CPU
>> locality or global ordering guarantees unless the target CPU is
>> explicitly specified and thus the increase of local concurrency shouldn't
>> make any difference.
>>
>> Since the work items could be pending, flush_work() has been used in
>> xen_pcibk_disconnect(). xen_pcibk_xenbus_remove() calls free_pdev()
>> which in turn calls xen_pcibk_disconnect() for every pdev to ensure that
>> there is no pending task while disconnecting the driver.
>>
>> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@...il.com>
>
> Acked-by: Tejun Heo <tj@...nel.org>
>
> Thanks.
>
> --
> tejun