Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752793AbYJYWYW (ORCPT ); Sat, 25 Oct 2008 18:24:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751246AbYJYWYN (ORCPT ); Sat, 25 Oct 2008 18:24:13 -0400 Received: from ozlabs.org ([203.10.76.45]:39136 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750850AbYJYWYM (ORCPT ); Sat, 25 Oct 2008 18:24:12 -0400 From: Rusty Russell To: Linus Torvalds Subject: Re: [PULL] module, param and stop_machine patches Date: Sun, 26 Oct 2008 09:24:08 +1100 User-Agent: KMail/1.9.10 Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andi Kleen , Heiko Carstens , "Greg Kroah-Hartman" , Arjan van de Ven , Hugh Dickins , walt References: <200810221005.59874.rusty@rustcorp.com.au> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200810260924.09479.rusty@rustcorp.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4022 Lines: 125 On Sunday 26 October 2008 08:17:38 Linus Torvalds wrote: > On Wed, 22 Oct 2008, Rusty Russell wrote: > > Heiko Carstens (4): > > Call init_workqueues before pre smp initcalls. > > This one actually causes a regression for me on one of my machines. Thanks, Heiko tracked this down; he's probably sleeping now but Hugh and Walt reported this fixes it for them and it makes sense. --- Subject: commit a802dd0e breaks console keyboard input Date: Sat, 25 Oct 2008 16:16:22 +0200 From: Heiko Carstens The patch below moves the init call to its old place but makes the stop_machine initialization happen later. I added a BUG_ON to catch possible early calls, but there shouldn't be any. I think the patch should solve the regression you are seeing. Could you give it a try please? The patch applies on top of latest Linus' git tree. Signed-off-by: Rusty Russell --- include/linux/stop_machine.h | 6 ++++++ init/main.c | 5 +++-- kernel/stop_machine.c | 9 ++++++--- 3 files changed, 15 insertions(+), 5 deletions(-) Index: linux-2.6/include/linux/stop_machine.h =================================================================== --- linux-2.6.orig/include/linux/stop_machine.h +++ linux-2.6/include/linux/stop_machine.h @@ -35,6 +35,9 @@ int stop_machine(int (*fn)(void *), void * won't come or go while it's being called. Used by hotplug cpu. */ int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus); + +void stop_machine_init(void); + #else static inline int stop_machine(int (*fn)(void *), void *data, @@ -46,5 +49,8 @@ static inline int stop_machine(int (*fn) local_irq_enable(); return ret; } + +static inline void stop_machine_init(void) { } + #endif /* CONFIG_SMP */ #endif /* _LINUX_STOP_MACHINE */ Index: linux-2.6/init/main.c =================================================================== --- linux-2.6.orig/init/main.c +++ linux-2.6/init/main.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #include #include @@ -768,6 +769,8 @@ static void __init do_initcalls(void) static void __init do_basic_setup(void) { rcu_init_sched(); /* needed by module_init stage. */ + init_workqueues(); + stop_machine_init(); usermodehelper_init(); driver_init(); init_irq_proc(); @@ -851,8 +854,6 @@ static int __init kernel_init(void * unu cad_pid = task_pid(current); - init_workqueues(); - smp_prepare_cpus(setup_max_cpus); do_pre_smp_initcalls(); Index: linux-2.6/kernel/stop_machine.c =================================================================== --- linux-2.6.orig/kernel/stop_machine.c +++ linux-2.6/kernel/stop_machine.c @@ -43,6 +43,7 @@ static struct workqueue_struct *stop_mac static struct stop_machine_data active, idle; static const cpumask_t *active_cpus; static void *stop_machine_work; +static int stop_machine_initialized; static void set_state(enum stopmachine_state newstate) { @@ -114,6 +115,7 @@ int __stop_machine(int (*fn)(void *), vo struct work_struct *sm_work; int i; + BUG_ON(!stop_machine_initialized); /* Set up initial state. */ mutex_lock(&lock); num_threads = num_online_cpus(); @@ -154,10 +156,11 @@ int stop_machine(int (*fn)(void *), void } EXPORT_SYMBOL_GPL(stop_machine); -static int __init stop_machine_init(void) +void __init stop_machine_init(void) { stop_machine_wq = create_rt_workqueue("kstop"); + BUG_ON(!stop_machine_wq); stop_machine_work = alloc_percpu(struct work_struct); - return 0; + BUG_ON(!stop_machine_work); + stop_machine_initialized = 1; } -early_initcall(stop_machine_init); -- 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/