Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753585AbZFXPDR (ORCPT ); Wed, 24 Jun 2009 11:03:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753048AbZFXPDG (ORCPT ); Wed, 24 Jun 2009 11:03:06 -0400 Received: from mail-qy0-f193.google.com ([209.85.221.193]:51382 "EHLO mail-qy0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752177AbZFXPDF convert rfc822-to-8bit (ORCPT ); Wed, 24 Jun 2009 11:03:05 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=bn128ERJXNy2j8jcbxwl2+Iz1DvhJjcwBX6/vnrb2dFBGYC1yBuYgIOd/R9f76vbPd pZz6s8QtQ9DqVMF36elPoOcy5l2cuxZCqkuy8wlVCjhR0mk4tyKr7BKPFVZ5loen6FBg QLRbt+9wtD44FjBlwX1X6lpm3tCGQC7CMaM3o= MIME-Version: 1.0 In-Reply-To: <200906241602.38422.arnd@arndb.de> References: <8bd0f97a0906231508s4c115d3dr2848626bc5a28c5e@mail.gmail.com> <20090624131357.GA6224@elte.hu> <200906241602.38422.arnd@arndb.de> From: Mike Frysinger Date: Wed, 24 Jun 2009 11:02:48 -0400 Message-ID: <8bd0f97a0906240802ieec96fav2864fa199d3f1b90@mail.gmail.com> Subject: Re: PREEMPT_ACTIVE too low error with all asm-generic headers for some arches To: Arnd Bergmann Cc: Ingo Molnar , Thomas Gleixner , Steven Rostedt , Linux kernel mailing list Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2271 Lines: 57 On Wed, Jun 24, 2009 at 10:02, Arnd Bergmann wrote: > On Wednesday 24 June 2009, Ingo Molnar wrote: >> * Mike Frysinger wrote: >> > if we look at linux/hardirq.h, it makes this claim: >> >  * - bit 28 is the PREEMPT_ACTIVE flag >> > if that's true, then why are we letting any arch set this define ?  a >> > quick survey shows that half the arches (11) are using 0x10000000 (bit >> > 28) while the other half (10) are using 0x4000000 (bit 26).  and then >> > there is the ia64 oddity which uses bit 30.  the exact value here >> > shouldnt really matter across arches though should it ? > > actually alpha, arm and avr32 also use bit 30 (0x40000000), there are only > five (or eight, depending on how you count) architectures (blackfin, h8300, > m68k, s390 and sparc) using bit 26. meh, too many zeros ;) >> Correct - what matters is to have no collision between the fields. >> >> > how about adding this to linux/thread_info.h: >> > #ifndef PREEMPT_ACTIVE >> > # ifndef PREEMPT_ACTIVE_BIT >> > #  define PREEMPT_ACTIVE_BIT 28 >> > # endif >> > # define PREEMPT_ACTIVE (1 << PREEMPT_ACTIVE_BIT) >> > #endif >> >> Makes sense i guess - but do we really need that level of >> #ifdef nesting? PREEMPT_ACTIVE_BIT should be the main control - with >> a default to 28 if it's not set. PREEMPT_ACTIVE is then derived off >> that, without any #ifdefs. > > I think it would fit better into linux/hardirq.h instead of > linux/thread_info.h, because that is where the other bits of > the preempt count are defined. agreed > --- a/include/linux/hardirq.h > +++ b/include/linux/hardirq.h > @@ -62,6 +62,12 @@ >  #define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT) >  #define NMI_OFFSET     (1UL << NMI_SHIFT) > > +#ifndef PREEMPT_ACTIVE > +#define PREEMPT_ACTIVE_BITS    1 > +#define PREEMPT_ACTIVE_SHIFT   (NMI_SHIFT + NMI_BITS) > +#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_SHIFT) i think you meant "<< PREEMPT_ACTIVE_SHIFT" there. once i make that change, it builds fine. -mike -- 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/