Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753763Ab0BWTTS (ORCPT ); Tue, 23 Feb 2010 14:19:18 -0500 Received: from david.siemens.de ([192.35.17.14]:15870 "EHLO david.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751665Ab0BWTTR (ORCPT ); Tue, 23 Feb 2010 14:19:17 -0500 Message-ID: <4B842A1F.50601@siemens.com> Date: Tue, 23 Feb 2010 20:18:55 +0100 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Thomas Gleixner , Avi Kivity CC: KVM , Gleb Natapov , RT , Linux Kernel Mailing List Subject: Re: [patch] x86: kvm: Convert i8254/i8259 locks to raw_spinlocks References: <20100217135901.331576359@linutronix.de> In-Reply-To: <20100217135901.331576359@linutronix.de> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 889 Lines: 23 Thomas Gleixner wrote: > The i8254/i8259 locks need to be real spinlocks on preempt-rt. Convert > them to raw_spinlock. No change for !RT kernels. Doesn't fly for -rt anymore: pic_irq_update runs under this raw lock and calls kvm_vcpu_kick which tries to wake_up some thread -> scheduling while atomic. This used to work up to 956f97cf. -rt for 2.6.31 is not yet affected, but 2.6.33 should be broken (haven't checked, using kvm-kmod over 2.6.31 ATM). I can provide a patch that restores the deferred kicking if it's acceptable for upstream. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- 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/