Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757522AbYLDKdt (ORCPT ); Thu, 4 Dec 2008 05:33:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753283AbYLDKdk (ORCPT ); Thu, 4 Dec 2008 05:33:40 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:56788 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753217AbYLDKdj (ORCPT ); Thu, 4 Dec 2008 05:33:39 -0500 Date: Thu, 4 Dec 2008 11:33:16 +0100 From: Ingo Molnar To: Peter Zijlstra Cc: Thomas Gleixner , linux-kernel , Linus Torvalds , oliver@hartkopp.net Subject: Re: [RFC PATCH] hrtimer: removing all ur callback modes Message-ID: <20081204103316.GB19494@elte.hu> References: <1227613431.4259.1537.camel@twins> <1228385830.5092.43.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1228385830.5092.43.camel@twins> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1701 Lines: 41 * Peter Zijlstra wrote: > On Tue, 2008-11-25 at 12:43 +0100, Peter Zijlstra wrote: > > Hi, > > > > This is an attempt at removing some of the hrtimer complexity by > > reducing the number of callback modes to 1. > > > > This means that all hrtimer callback functions will be ran from HARD-irq > > context. > > > > I went through all the 30 odd hrtimer callback functions in the kernel > > and saw only one that I'm not quite sure of, which is the one in > > net/can/bcm.c - hence I'm CC-ing the folks responsible for that code. > > > > Furthermore, the hrtimer core now calls callbacks directly with IRQs > > disabled in case you try to enqueue an expired timer. If this timer is a > > periodic timer (which should use hrtimer_forward() to advance its time) > > then it might be possible to end up in an inf. recursive loop due to the > > fact that hrtimer_forward() doesn't round up to the next timer > > granularity, and therefore keeps on calling the callback - obviously > > this needs a fix. > > > > Aside from that, this seems to compile and actually boot on my dual core > > test box - although I'm sure there are some bugs in, me not hitting any > > makes me certain :-) > > > > Not-Quite-Signed-off-by: Peter Zijlstra > > Ingo, this addition fixes the hotplug issue on my machine thanks, applied - i also reactivated the tip/timers/hrtimer topic branch - lets see how it goes now. 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/