From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752551AbcF2Mtl (ORCPT <rfc822;w@1wt.eu>);
	Wed, 29 Jun 2016 08:49:41 -0400
Received: from smtp02.citrix.com ([66.165.176.63]:64425 "EHLO
	SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751767AbcF2Mtk (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 29 Jun 2016 08:49:40 -0400
X-IronPort-AV: E=Sophos;i="5.26,546,1459814400"; 
   d="scan'208";a="370347210"
Subject: Re: [Xen-devel] [PATCH v2] xen: xen-pciback: Remove create_workqueue
To: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        David Vrabel <david.vrabel@citrix.com>,
        "Juergen Gross" <jgross@suse.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        "Jan Beulich" <JBeulich@suse.com>,
        Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Doug Goldstein <cardoe@cardoe.com>
References: <20160601141508.GA27853@Karyakshetra>
CC: Tejun Heo <tj@kernel.org>, <xen-devel@lists.xenproject.org>,
        <linux-kernel@vger.kernel.org>
From: David Vrabel <david.vrabel@citrix.com>
Message-ID: <5773C3DC.60804@citrix.com>
Date: Wed, 29 Jun 2016 13:49:32 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101
 Icedove/38.5.0
MIME-Version: 1.0
In-Reply-To: <20160601141508.GA27853@Karyakshetra>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
X-DLP: MIA1
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 01/06/16 15:15, 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.

Applied to for-linus-4.8, thanks.

David