Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753285Ab3IIOto (ORCPT ); Mon, 9 Sep 2013 10:49:44 -0400 Received: from a9-99.smtp-out.amazonses.com ([54.240.9.99]:54125 "EHLO a9-99.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751640Ab3IIOtn (ORCPT ); Mon, 9 Sep 2013 10:49:43 -0400 Date: Mon, 9 Sep 2013 14:49:42 +0000 From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Peter Zijlstra cc: "Paul E. McKenney" , Frederic Weisbecker , Eric Dumazet , linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, sbw@mit.edu Subject: Re: [PATCH] rcu: Is it safe to enter an RCU read-side critical section? In-Reply-To: <20130909133604.GC31370@twins.programming.kicks-ass.net> Message-ID: <000001410333127c-486c74ec-3209-4c5e-a92f-0c11e00fa141-000000@email.amazonses.com> References: <20130905195234.GA20555@linux.vnet.ibm.com> <20130906105934.GF20519@somewhere> <20130906151851.GQ3966@linux.vnet.ibm.com> <1378488088.31445.39.camel@edumazet-glaptop> <20130906174117.GU3966@linux.vnet.ibm.com> <20130906185927.GE2706@somewhere> <20130909105347.GK31370@twins.programming.kicks-ass.net> <20130909132343.GN3966@linux.vnet.ibm.com> <20130909133604.GC31370@twins.programming.kicks-ass.net> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SES-Outgoing: 2013.09.09-54.240.9.99 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1146 Lines: 23 On Mon, 9 Sep 2013, Peter Zijlstra wrote: > On Mon, Sep 09, 2013 at 06:23:43AM -0700, Paul E. McKenney wrote: > > And guys, I have to say that the advice on which per-CPU primitive to use > > varies wildly and randomly. For all I know, each of you individually > > might well be sticking to the same story, but taken together, your > > collective advice is strongly resembling white noise. > > Its partly because cl and I disagree on things. He doesn't seem to care > much about validation and believes that people will not make mistakes > with this stuff. Slander. Certainly validation is good. Its just that PREEMPT kernels are not in use and AFAICT the full preempt stuff requires significant developer support and complicates the code without much benefit. Having said that I am trying to support preeempt checks. The newest __get_cpu_var patchset introduces the preempt checks that you want. -- 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/