Make __stop_machine_run accepts 'cpumask_t' parameter and
multiple cpus be able to run specified task.
Signed-off-by: Ashok Raj <[email protected]>
Signed-off-by: Shaohua Li <[email protected]>
---
linux-2.6.17-rc3-root/include/linux/stop_machine.h | 4 -
linux-2.6.17-rc3-root/kernel/cpu.c | 2
linux-2.6.17-rc3-root/kernel/stop_machine.c | 68 ++++++++++++++-------
3 files changed, 50 insertions(+), 24 deletions(-)
diff -puN include/linux/stop_machine.h~stopmachine-run-accept-cpumask include/linux/stop_machine.h
--- linux-2.6.17-rc3/include/linux/stop_machine.h~stopmachine-run-accept-cpumask 2006-05-07 07:44:34.000000000 +0800
+++ linux-2.6.17-rc3-root/include/linux/stop_machine.h 2006-05-07 07:44:34.000000000 +0800
@@ -28,14 +28,14 @@ int stop_machine_run(int (*fn)(void *),
* __stop_machine_run: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn
- * @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
+ * @cpus: the cpus to run @fn on.
*
* Description: This is a special version of the above, which returns the
* thread which has run @fn(): kthread_stop will return the return value
* of @fn(). Used by hotplug cpu.
*/
struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
- unsigned int cpu);
+ cpumask_t cpus);
#else
diff -puN kernel/cpu.c~stopmachine-run-accept-cpumask kernel/cpu.c
--- linux-2.6.17-rc3/kernel/cpu.c~stopmachine-run-accept-cpumask 2006-05-07 07:44:34.000000000 +0800
+++ linux-2.6.17-rc3-root/kernel/cpu.c 2006-05-07 07:44:34.000000000 +0800
@@ -148,7 +148,7 @@ int cpu_down(unsigned int cpu)
cpu_clear(cpu, tmp);
set_cpus_allowed(current, tmp);
- p = __stop_machine_run(take_cpu_down, NULL, cpu);
+ p = __stop_machine_run(take_cpu_down, NULL, cpumask_of_cpu(cpu));
if (IS_ERR(p)) {
/* CPU didn't die: tell everyone. Can't complain. */
if (blocking_notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
diff -puN kernel/stop_machine.c~stopmachine-run-accept-cpumask kernel/stop_machine.c
--- linux-2.6.17-rc3/kernel/stop_machine.c~stopmachine-run-accept-cpumask 2006-05-07 07:44:34.000000000 +0800
+++ linux-2.6.17-rc3-root/kernel/stop_machine.c 2006-05-07 07:44:34.000000000 +0800
@@ -17,18 +17,31 @@ enum stopmachine_state {
STOPMACHINE_WAIT,
STOPMACHINE_PREPARE,
STOPMACHINE_DISABLE_IRQ,
+ STOPMACHINE_PREPARE_TASK,
+ STOPMACHINE_FINISH_TASK,
STOPMACHINE_EXIT,
};
+struct stop_machine_data
+{
+ cpumask_t task_cpus;
+ int (*fn)(void *);
+ void *data;
+ struct completion done;
+};
+
static enum stopmachine_state stopmachine_state;
static unsigned int stopmachine_num_threads;
static atomic_t stopmachine_thread_ack;
static DECLARE_MUTEX(stopmachine_mutex);
+static struct stop_machine_data *smdata;
static int stopmachine(void *cpu)
{
int irqs_disabled = 0;
int prepared = 0;
+ int task_prepared = 0;
+ int task_finished = 0;
set_cpus_allowed(current, cpumask_of_cpu((int)(long)cpu));
@@ -52,7 +65,22 @@ static int stopmachine(void *cpu)
prepared = 1;
smp_mb(); /* Must read state first. */
atomic_inc(&stopmachine_thread_ack);
+ } else if (stopmachine_state == STOPMACHINE_PREPARE_TASK
+ && !task_prepared) {
+ task_prepared = 1;
+ smp_mb(); /* Must read state first. */
+ atomic_inc(&stopmachine_thread_ack);
+ /* do the task */
+ if (cpu_isset((int)(long)cpu, smdata->task_cpus))
+ smdata->fn(smdata->data);
+ } else if (stopmachine_state == STOPMACHINE_FINISH_TASK
+ && !task_finished) {
+ task_finished = 1;
+ smp_mb(); /* Must read state first. */
+ atomic_inc(&stopmachine_thread_ack);
}
+
+
/* Yield in first stage: migration threads need to
* help our sisters onto their CPUs. */
if (!prepared && !irqs_disabled)
@@ -133,21 +161,18 @@ static void restart_machine(void)
preempt_enable_no_resched();
}
-struct stop_machine_data
-{
- int (*fn)(void *);
- void *data;
- struct completion done;
-};
static int do_stop(void *_smdata)
{
- struct stop_machine_data *smdata = _smdata;
int ret;
ret = stop_machine();
if (ret == 0) {
+ stopmachine_set_state(STOPMACHINE_PREPARE_TASK);
+ /* only record first cpu's return value */
ret = smdata->fn(smdata->data);
+ /* wait peers finish task */
+ stopmachine_set_state(STOPMACHINE_FINISH_TASK);
restart_machine();
}
@@ -165,27 +190,25 @@ static int do_stop(void *_smdata)
}
struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
- unsigned int cpu)
+ cpumask_t cpus)
{
- struct stop_machine_data smdata;
+ struct stop_machine_data tmp;
struct task_struct *p;
- smdata.fn = fn;
- smdata.data = data;
- init_completion(&smdata.done);
+ tmp.fn = fn;
+ tmp.data = data;
+ tmp.task_cpus = cpus;
+ init_completion(&tmp.done);
down(&stopmachine_mutex);
-
- /* If they don't care which CPU fn runs on, bind to any online one. */
- if (cpu == NR_CPUS)
- cpu = raw_smp_processor_id();
-
- p = kthread_create(do_stop, &smdata, "kstopmachine");
+ smdata = &tmp;
+ p = kthread_create(do_stop, NULL, "kstopmachine");
if (!IS_ERR(p)) {
- kthread_bind(p, cpu);
+ kthread_bind(p, first_cpu(cpus));
wake_up_process(p);
- wait_for_completion(&smdata.done);
+ wait_for_completion(&smdata->done);
}
+ smdata = NULL;
up(&stopmachine_mutex);
return p;
}
@@ -197,7 +220,10 @@ int stop_machine_run(int (*fn)(void *),
/* No CPUs can come up or down during this. */
lock_cpu_hotplug();
- p = __stop_machine_run(fn, data, cpu);
+ /* If they don't care which CPU fn runs on, bind to any online one. */
+ if (cpu == NR_CPUS)
+ cpu = raw_smp_processor_id();
+ p = __stop_machine_run(fn, data, cpumask_of_cpu(cpu));
if (!IS_ERR(p))
ret = kthread_stop(p);
else
_
-
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