[PATCH] kthread: convert stop_machine into a kthread
Serge E. Hallyn [Sun, 25 Jun 2006 12:49:08 +0000 (05:49 -0700)]
- Update stop_machine.c to spawn stop_machine as kthreads rather than the
  deprecated kernel_threads.

- Update stop_machine to use the more efficient kthread_bind() before
  running task in place of set_cpus_allowed() after.

[akpm@osdl.org: remove now-wrong set_cpus_allowed()]
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

kernel/stop_machine.c

index dcfb5d7..2c0aacc 100644 (file)
@@ -4,6 +4,7 @@
 #include <linux/cpu.h>
 #include <linux/err.h>
 #include <linux/syscalls.h>
+#include <linux/kthread.h>
 #include <asm/atomic.h>
 #include <asm/semaphore.h>
 #include <asm/uaccess.h>
@@ -25,13 +26,11 @@ static unsigned int stopmachine_num_threads;
 static atomic_t stopmachine_thread_ack;
 static DECLARE_MUTEX(stopmachine_mutex);
 
-static int stopmachine(void *cpu)
+static int stopmachine(void *unused)
 {
        int irqs_disabled = 0;
        int prepared = 0;
 
-       set_cpus_allowed(current, cpumask_of_cpu((int)(long)cpu));
-
        /* Ack: we are alive */
        smp_mb(); /* Theoretically the ack = 0 might not be on this CPU yet. */
        atomic_inc(&stopmachine_thread_ack);
@@ -85,7 +84,8 @@ static void stopmachine_set_state(enum stopmachine_state state)
 
 static int stop_machine(void)
 {
-       int i, ret = 0;
+       int ret = 0;
+       unsigned int i;
        struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
 
        /* One high-prio thread per cpu.  We'll do this one. */
@@ -96,11 +96,16 @@ static int stop_machine(void)
        stopmachine_state = STOPMACHINE_WAIT;
 
        for_each_online_cpu(i) {
+               struct task_struct *tsk;
                if (i == raw_smp_processor_id())
                        continue;
-               ret = kernel_thread(stopmachine, (void *)(long)i,CLONE_KERNEL);
-               if (ret < 0)
+               tsk = kthread_create(stopmachine, NULL, "stopmachine");
+               if (IS_ERR(tsk)) {
+                       ret = PTR_ERR(tsk);
                        break;
+               }
+               kthread_bind(tsk, i);
+               wake_up_process(tsk);
                stopmachine_num_threads++;
        }