From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH 1/10] Add generic helpers for arch IPI function calls Date: Wed, 7 May 2008 21:36:13 -0700 Message-ID: <20080508043613.GB20338@linux.vnet.ibm.com> References: <20080502020241.GA26088@linux.vnet.ibm.com> <20080502021233.GC11844@wotan.suse.de> <20080502122955.GB15522@linux.vnet.ibm.com> <20080502124205.GA23680@linux.vnet.ibm.com> <1209733169.13978.157.camel@twins> <20080503054930.GA19664@wotan.suse.de> <20080503181148.GA16159@linux.vnet.ibm.com> <20080505041533.GA17640@wotan.suse.de> <20080505174312.GC7543@linux.vnet.ibm.com> <20080507204251.GO16217@kernel.dk> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:55049 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136AbYEHEgT (ORCPT ); Thu, 8 May 2008 00:36:19 -0400 Content-Disposition: inline In-Reply-To: <20080507204251.GO16217@kernel.dk> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Jens Axboe Cc: Nick Piggin , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, jeremy@goop.org, mingo@elte.hu On Wed, May 07, 2008 at 10:42:52PM +0200, Jens Axboe wrote: > On Mon, May 05 2008, Paul E. McKenney wrote: > > OK. The below still permits parallel smp_call_function() > > and smp_call_function_mask() as well as permitting parallel > > smp_call_function_single(). It prohibits the irq-disabled case. > > > > Thoughts? > > Sorry for the delayed response here. The below looks pretty good to me, > though it'll require a few modifications to fixup smp_call_function() > from irq disabled context. Yep, easy fix, even if wait==1 needed. > But that's doable, though I have to do a grep over the kernel to check > everything (I remember CPU send_stop being one such path). Not a huge > fan of such an interface, but hey... > > Is everyone OK with going this route, initially at least? It's the > lesser of all evils, I think. > > > diff --git a/arch/Kconfig b/arch/Kconfig > > index a5a0184..5ae9360 100644 > > --- a/arch/Kconfig > > +++ b/arch/Kconfig > > @@ -38,4 +38,4 @@ config HAVE_KRETPROBES > > def_bool n > > > > config USE_GENERIC_SMP_HELPERS > > - def_bool n > > + def_bool y > > This part puzzled me, why? We default to 'n' and let converted archs > opt-in, so I don't get this part of your patch... I made that change to get it to compile, and forgot to revert it when making the patch. Please ignore that bit. Thanx, Paul