Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965467AbWI0JXG (ORCPT ); Wed, 27 Sep 2006 05:23:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965468AbWI0JXG (ORCPT ); Wed, 27 Sep 2006 05:23:06 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:50334 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S965467AbWI0JXD (ORCPT ); Wed, 27 Sep 2006 05:23:03 -0400 Date: Wed, 27 Sep 2006 11:15:13 +0200 From: Ingo Molnar To: Bill Huey Cc: "Eric W. Biederman" , linux-kernel@vger.kernel.org, Thomas Gleixner , John Stultz , "Paul E. McKenney" , Dipankar Sarma , Arjan van de Ven Subject: Re: [PATCH] move put_task_struct() reaping into a thread [Re: 2.6.18-rt1] Message-ID: <20060927091513.GC20395@elte.hu> References: <20060920141907.GA30765@elte.hu> <20060921065624.GA9841@gnuppy.monkey.org> <20060927050856.GA16140@gnuppy.monkey.org> <20060927085712.GA16938@elte.hu> <20060927091456.GB17136@gnuppy.monkey.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060927091456.GB17136@gnuppy.monkey.org> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.9 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.1 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1266 Lines: 29 * Bill Huey wrote: > On Wed, Sep 27, 2006 at 10:57:12AM +0200, Ingo Molnar wrote: > > * Bill Huey wrote: > > > > > Because the conversion of memory allocation routines like kmalloc and > > > kfree aren't safely callable within a preempt_disable critical section > > > since they were incompletely converted in the -rt. [...] > > > > they were not 'incompletely converted' - they are /intentionally/ fully > > preemptible. > > What I meant by "incompletely converted" is that the allocators could > be made more safe in non-preemptible scenarios under -rt. [...] no, the -rt kernel intentionally does not do that and wont do that. There's lots of complex stuff going on within allocators, even in the GFP_ATOMIC path. We might be able to plug in more deterministic allocators (like SLOB), but even they must be fully preemptible. In the -rt kernel there's basically no compromise on the "do as little as possible in non-preemptible regions" stance. Ingo - 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/