From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755864Ab1FHUyt (ORCPT ); Wed, 8 Jun 2011 16:54:49 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:46642 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755487Ab1FHUyq (ORCPT ); Wed, 8 Jun 2011 16:54:46 -0400 MIME-Version: 1.0 In-Reply-To: <1307565125.2497.1003.camel@laptop> References: <20110606155236.GA7374@elte.hu> <1307376039.2322.164.camel@twins> <20110606160810.GA16636@elte.hu> <1307376771.2322.168.camel@twins> <20110606161749.GA22157@elte.hu> <4DED0292.1040605@die-jansens.de> <4DED0423.4050904@die-jansens.de> <20110606170725.GD2391@elte.hu> <1307380311.2322.223.camel@twins> <1307548218.3941.6.camel@twins> <20110608191758.GA12457@elte.hu> <1307565125.2497.1003.camel@laptop> From: Linus Torvalds Date: Wed, 8 Jun 2011 13:53:48 -0700 Message-ID: Subject: Re: [debug patch] printk: Add a printk killswitch to robustify NMI watchdog messages To: Peter Zijlstra Cc: Ingo Molnar , Arne Jansen , mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, efault@gmx.de, npiggin@kernel.dk, akpm@linux-foundation.org, frank.rowand@am.sony.com, tglx@linutronix.de, linux-tip-commits@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 8, 2011 at 1:32 PM, Peter Zijlstra wrote: > > atomic_down() is a tad iffy, it would have to wait for an actual > semaphore owner, which might sleep etc.. So I skipped it. I think sleeping would be fine: the "atomic" part is about the code the semaphore protects, not about the down() itself. But the way you made the semantics be (caller has to disable interrupts) for the other helpers, that doesn't really work. Linus