Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760519AbYBOR7S (ORCPT ); Fri, 15 Feb 2008 12:59:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759380AbYBOR6i (ORCPT ); Fri, 15 Feb 2008 12:58:38 -0500 Received: from x346.tv-sign.ru ([89.108.83.215]:58477 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759203AbYBOR6h (ORCPT ); Fri, 15 Feb 2008 12:58:37 -0500 Date: Fri, 15 Feb 2008 21:01:54 +0300 From: Oleg Nesterov To: Andrew Morton Cc: Arjan van de Ven , Heiko Carstens , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: [PATCH 1/3] timers: simplify lockdep stuff Message-ID: <20080215180154.GA4347@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1973 Lines: 60 In order to avoid the false positive from lockdep, each per-cpu base->lock has the separate lock class and migrate_timers() uses double_spin_lock(). This all is overcomplicated: except for migrate_timers() we never take 2 locks at once, and migrate_timers() can use spin_lock_nested(). Signed-off-by: Oleg Nesterov --- 25/kernel/timer.c~2_TIMERS 2008-02-15 16:59:18.000000000 +0300 +++ 25/kernel/timer.c 2008-02-15 19:17:29.000000000 +0300 @@ -1220,13 +1220,6 @@ asmlinkage long sys_sysinfo(struct sysin return 0; } -/* - * lockdep: we want to track each per-CPU base as a separate lock-class, - * but timer-bases are kmalloc()-ed, so we need to attach separate - * keys to them: - */ -static struct lock_class_key base_lock_keys[NR_CPUS]; - static int __cpuinit init_timers_cpu(int cpu) { int j; @@ -1269,7 +1262,6 @@ static int __cpuinit init_timers_cpu(int } spin_lock_init(&base->lock); - lockdep_set_class(&base->lock, base_lock_keys + cpu); for (j = 0; j < TVN_SIZE; j++) { INIT_LIST_HEAD(base->tv5.vec + j); @@ -1308,8 +1300,8 @@ static void __cpuinit migrate_timers(int new_base = get_cpu_var(tvec_bases); local_irq_disable(); - double_spin_lock(&new_base->lock, &old_base->lock, - smp_processor_id() < cpu); + spin_lock(&new_base->lock); + spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING); BUG_ON(old_base->running_timer); @@ -1322,8 +1314,8 @@ static void __cpuinit migrate_timers(int migrate_timer_list(new_base, old_base->tv5.vec + i); } - double_spin_unlock(&new_base->lock, &old_base->lock, - smp_processor_id() < cpu); + spin_unlock(&old_base->lock); + spin_unlock(&new_base->lock); local_irq_enable(); put_cpu_var(tvec_bases); } -- 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/