linux-kernel - Re: Overview of concurrency managed workqueue

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

Message-ID: <1276776066.2461.15.camel@localhost>
Date:	Thu, 17 Jun 2010 08:01:06 -0400
From:	Andy Walls <awalls@...metrocast.net>
To:	Daniel Walker <dwalker@...eaurora.org>
Cc:	Tejun Heo <tj@...nel.org>, mingo@...e.hu,
	linux-kernel@...r.kernel.org, jeff@...zik.org,
	akpm@...ux-foundation.org, rusty@...tcorp.com.au,
	cl@...ux-foundation.org, dhowells@...hat.com,
	arjan@...ux.intel.com, johannes@...solutions.net, oleg@...hat.com,
	axboe@...nel.dk
Subject: Re: Overview of concurrency managed workqueue

On Wed, 2010-06-16 at 07:05 -0700, Daniel Walker wrote:
> On Wed, 2010-06-16 at 15:45 +0200, Tejun Heo wrote:
> > On 06/16/2010 03:41 PM, Daniel Walker wrote:
> > > Any workqueue that has a thread which can be prioritized from userspace.
> > > As long as there is a thread it can usually be given a priority from
> > > userspace, so any _current_ workqueue which uses a single thread or
> > > multiple threads is an example of what I'm talking about.
> > 
> > Eh... what's the use case for that?  That's just so wrong.  What do
> > you do after a suspend/resume cycle?  Reprioritize all of them from
> > suspend/resume hooks?
> 
> The use case is any situation when the user wants to give higher
> priority to some set of work items, and there's nothing wrong with that.
> In fact there has been a lot of work in the RT kernel related to
> workqueue prioritization ..

I'm going to agree with Tejun, that tweaking worker thread priorities
seems like an odd thing, since they are meant to handle deferable
actions - things that can be put off until later.

If one needs to support Real Time deadlines on deferable actions,
wouldn't using dedicated kernel threads be more deterministic?
Would the user ever up the priority for a workqueue other than a
single-threaded workqueue?

Regards,
Andy

> Daniel



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/