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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <5773C3DC.60804@citrix.com>
Date:	Wed, 29 Jun 2016 13:49:32 +0100
From:	David Vrabel <david.vrabel@...rix.com>
To:	Bhaktipriya Shridhar <bhaktipriya96@...il.com>,
	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>
CC:	Tejun Heo <tj@...nel.org>, <xen-devel@...ts.xenproject.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [Xen-devel] [PATCH v2] xen: xen-pciback: Remove create_workqueue

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