Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759969AbXFVWLc (ORCPT ); Fri, 22 Jun 2007 18:11:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753775AbXFVWLY (ORCPT ); Fri, 22 Jun 2007 18:11:24 -0400 Received: from dsl081-033-126.lax1.dsl.speakeasy.net ([64.81.33.126]:33491 "EHLO bifrost.lang.hm" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753246AbXFVWLY (ORCPT ); Fri, 22 Jun 2007 18:11:24 -0400 Date: Fri, 22 Jun 2007 15:09:21 -0700 (PDT) From: david@lang.hm X-X-Sender: dlang@asgard.lang.hm To: Daniel Walker cc: Ingo Molnar , Linus Torvalds , Steven Rostedt , LKML , Andrew Morton , Thomas Gleixner , Christoph Hellwig , john stultz , Oleg Nesterov , "Paul E. McKenney" , Dipankar Sarma , "David S. Miller" , matthew.wilcox@hp.com, kuznet@ms2.inr.ac.ru Subject: Re: [RFC PATCH 0/6] Convert all tasklets to workqueues In-Reply-To: <1182549202.3228.78.camel@dhcp193.mvista.com> Message-ID: References: <20070622040014.234651401@goodmis.org> <20070622204058.GA11777@elte.hu> <1182549202.3228.78.camel@dhcp193.mvista.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1447 Lines: 35 On Fri, 22 Jun 2007, Daniel Walker wrote: > > On Fri, 2007-06-22 at 22:40 +0200, Ingo Molnar wrote: > >> >> - tasklets have certain fairness limitations. (they are executed in >> softirq context and thus preempt everything, even if there is some >> potentially more important, high-priority task waiting to be >> executed.) > > Since -rt has been executing tasklets in process context for a long > time, I'm not sure this change would cause to many regressions. However, > it seems like implicit dependencies on "tasklets preempt everything" > might crop up. The other issue is if they don't "preempt > everything" (most of the time), what default priority do we give them > (all of the time)? It seems like Christoph's suggestion of converting > all the tasklets individually might be a better option, to deal with > specific pitfalls. that would be the safe way to do it, but it will take a lot of time and a lot of testing. it's probably better to try the big-bang change and only if you see problames go back and break things down. remember, these changes have been in use in -rt for a while. there's reason to believe that they aren't going to cause drastic problems. David Lang - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/