From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755533AbZHYR5p (ORCPT ); Tue, 25 Aug 2009 13:57:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755485AbZHYR5o (ORCPT ); Tue, 25 Aug 2009 13:57:44 -0400 Received: from mga11.intel.com ([192.55.52.93]:7095 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755457AbZHYR5n (ORCPT ); Tue, 25 Aug 2009 13:57:43 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.44,273,1249282800"; d="scan'208";a="487263192" Subject: Re: [tip:x86/pat] generic-ipi: Allow cpus not yet online to call smp_call_function with irqs disabled From: Suresh Siddha Reply-To: Suresh Siddha To: Nick Piggin Cc: "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "hpa@zytor.com" , "tglx@linutronix.de" , "linux-tip-commits@vger.kernel.org" In-Reply-To: <20090825042956.GU25721@wotan.suse.de> References: <20090824054026.GR25721@wotan.suse.de> <1251144943.2636.16.camel@sbs-t61> <20090825042956.GU25721@wotan.suse.de> Content-Type: text/plain Organization: Intel Corp Date: Tue, 25 Aug 2009 10:56:53 -0700 Message-Id: <1251223013.2612.11.camel@sbs-t61> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2009-08-24 at 21:29 -0700, Nick Piggin wrote: > On Mon, Aug 24, 2009 at 01:15:43PM -0700, Suresh B wrote: > > On Sun, 2009-08-23 at 22:40 -0700, Nick Piggin wrote: > > > Also, I would say that we should just restrict this to wait==1 case > > > because in that case the stack can trivially be used for data. In > > > the wait==0 case, it is more complex. In the current implementation > > > it should be OK (it uses per-cpu data), but we've used kmalloc > > > there in the past, which probably wouldn't work either. > > > > In future if we add any kmalloc, we already have checks in kmalloc() > > that can be easily caught. I would like to make this change as generic > > as possible. > > Why? You think there will be much demand for it? In the current mtrr case, we currently use wait==0 Also unless there are issues, I would like to keep it open. So that it will encourage more usages and expose any other bugs that we perhaps overlooked. With all the recent generic-ipi changes, even for online cpu's, we should be able to allow smp_call_function() with interrupts disabled for wait==0 case, right? thanks, suresh