Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753465AbYADNs5 (ORCPT ); Fri, 4 Jan 2008 08:48:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752230AbYADNst (ORCPT ); Fri, 4 Jan 2008 08:48:49 -0500 Received: from ms-smtp-01.nyroc.rr.com ([24.24.2.55]:60623 "EHLO ms-smtp-01.nyroc.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751015AbYADNss (ORCPT ); Fri, 4 Jan 2008 08:48:48 -0500 Date: Fri, 4 Jan 2008 08:48:03 -0500 (EST) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Gautham R Shenoy cc: Paul E McKenney , "K. Prasad" , mingo@elte.hu, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, dipankar@in.ibm.com, Mathieu Desnoyers Subject: Re: __get_cpu_var() called from a preempt-unsafe context in __rcu_preempt_unboost() ? In-Reply-To: <20080104120905.GA15640@in.ibm.com> Message-ID: References: <20071231060911.GB6461@in.ibm.com> <20080103163055.GB27651@Krystal> <20080104120905.GA15640@in.ibm.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 807 Lines: 23 On Fri, 4 Jan 2008, Gautham R Shenoy wrote: > | > |--> rcu_trace_boost_unboost_called(RCU_BOOST_ME) > > > where RCU_BOOST_ME is #defined as &__get_cpu_var(rcu_boost_data). > > Is calling __get_cpu_var() safe in this context, since we've already > enabled the local interrupts and we're not in a preempt_disabled() ? Probably not, but the worst that can happen is that we corrupt the trace counter, and miss an increment. I'll see if I can fix that, but it should be quite harmless wrt the stability of the system. Thanks for pointing that out. -- Steve -- 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/