Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751922Ab1FOGFW (ORCPT ); Wed, 15 Jun 2011 02:05:22 -0400 Received: from mail-yi0-f46.google.com ([209.85.218.46]:61509 "EHLO mail-yi0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750887Ab1FOGFS convert rfc822-to-8bit (ORCPT ); Wed, 15 Jun 2011 02:05:18 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=umhvijiqdwI0ixp+Rg6oYcPr9JmpA4fQlLm9D+MiddTlM5ci8WCWO2lUz4i0NXFJIJ wF4Ka3hc+XoiDoPJFKx/f2wSFEm3o/QKpliPlaYLopATtEJ6qe6EMKxDQGvBOu1OlDV/ ddchSZrXevX4NAF1G2hsV6P7hnlgJlwzV+Fk0= MIME-Version: 1.0 In-Reply-To: References: Date: Wed, 15 Jun 2011 12:05:17 +0600 Message-ID: Subject: Re: [PATCH 1 of 6] x86, UV: smp_processor_id in a preemptable region From: Rakib Mullick To: Cliff Wickman Cc: linux-kernel@vger.kernel.org, mingo@elte.hu Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1626 Lines: 43 On Wed, Jun 15, 2011 at 5:06 AM, Cliff Wickman wrote: > From: Cliff Wickman > > Calling smp_processor_id() from within a preemptable region will issue > a warning if DEBUG_PREEMPT is set. > > Diffed against 3.0.0-rc3 > > Signed-off-by: Cliff Wickman > --- > ?arch/x86/platform/uv/tlb_uv.c | ? ?2 ++ > ?1 file changed, 2 insertions(+) > > Index: linux/arch/x86/platform/uv/tlb_uv.c > =================================================================== > --- linux.orig/arch/x86/platform/uv/tlb_uv.c > +++ linux/arch/x86/platform/uv/tlb_uv.c > @@ -1334,7 +1334,9 @@ static ssize_t tunables_write(struct fil > > ? ? ? ?instr[count] = '\0'; > > + ? ? ? preempt_disable(); /* avoid DEBUG_PREEMPT warning */ I think above code comment, "avoid DEBUG_PREEMPT warning" should be to something more meaningful. It's a BUG, if smp_processor_id() is called within preemptible context. So, we don't want to hit that BUG. > ? ? ? ?bcp = &per_cpu(bau_control, smp_processor_id()); > + ? ? ? preempt_enable_no_resched(); > > ? ? ? ?ret = parse_tunables_write(bcp, instr, count); > ? ? ? ?if (ret) > -- > 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/ > -- 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/