Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750886AbVJTW0l (ORCPT ); Thu, 20 Oct 2005 18:26:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750889AbVJTW0k (ORCPT ); Thu, 20 Oct 2005 18:26:40 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:63973 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1750862AbVJTW0k (ORCPT ); Thu, 20 Oct 2005 18:26:40 -0400 Date: Fri, 21 Oct 2005 00:27:03 +0200 From: Ingo Molnar To: Linus Torvalds Cc: Arjan van de Ven , Andrew Morton , Eric Dumazet , linux-kernel@vger.kernel.org Subject: Re: [PATCH] i386 spinlocks should use the full 32 bits, not only 8 bits Message-ID: <20051020222703.GA28221@elte.hu> References: <434BDB1C.60105@cosmosbay.com> <434BEA0D.9010802@cosmosbay.com> <20051017000343.782d46fc.akpm@osdl.org> <1129533603.2907.12.camel@laptopd505.fenrus.org> <20051020215047.GA24178@elte.hu> <20051020220228.GA26247@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: 0.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=0.0 required=5.9 tests=AWL autolearn=disabled SpamAssassin version=3.0.4 0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2033 Lines: 55 * Linus Torvalds wrote: > > > On Fri, 21 Oct 2005, Ingo Molnar wrote: > > > > the unlock is simple even in the preemption case > > No it's not. It needs to decrement the preemption counter and test it. arghhh. Right you are. I even had the proper solution coded up initially (i had || defined(CONFIG_PREEMPT)) but dropped it due to fatal brain error. Been hacking on way too much ktimer code today ... Hopefully better patch attached. Booted on SMP+PREEMPT x86. But i'd really advise you against taking patches from me tonight :-| Ingo Signed-off-by: Ingo Molnar include/linux/spinlock.h | 15 ++++++++++++--- 1 files changed, 12 insertions(+), 3 deletions(-) Index: linux/include/linux/spinlock.h =================================================================== --- linux.orig/include/linux/spinlock.h +++ linux/include/linux/spinlock.h @@ -171,9 +171,18 @@ extern int __lockfunc generic__raw_read_ #define write_lock_irq(lock) _write_lock_irq(lock) #define write_lock_bh(lock) _write_lock_bh(lock) -#define spin_unlock(lock) _spin_unlock(lock) -#define write_unlock(lock) _write_unlock(lock) -#define read_unlock(lock) _read_unlock(lock) +/* + * We inline the unlock functions in the nondebug case: + */ +#if defined(CONFIG_DEBUG_SPINLOCK) || defined(CONFIG_PREEMPT) +# define spin_unlock(lock) _spin_unlock(lock) +# define read_unlock(lock) _read_unlock(lock) +# define write_unlock(lock) _write_unlock(lock) +#else +# define spin_unlock(lock) __raw_spin_unlock(&(lock)->raw_lock) +# define read_unlock(lock) __raw_read_unlock(&(lock)->raw_lock) +# define write_unlock(lock) __raw_write_unlock(&(lock)->raw_lock) +#endif #define spin_unlock_irqrestore(lock, flags) \ _spin_unlock_irqrestore(lock, flags) - 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/