Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Re: [PULL] module, param and stop_machine patches | Date | Sun, 26 Oct 2008 09:24:08 +1100 |
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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 <heiko.carstens@de.ibm.com>
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 <rusty@rustcorp.com.au> --- 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 <linux/moduleparam.h> #include <linux/kallsyms.h> #include <linux/writeback.h> +#include <linux/stop_machine.h> #include <linux/cpu.h> #include <linux/cpuset.h> #include <linux/cgroup.h> @@ -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);
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