kernel/kthread.c:kthread_create_on_node(): clarify documentation

- Make it clear that the `node' arg refers to memory allocations only: kthread_create_on_node() does not pin the new thread to that node's CPUs. - Encourage the use of NUMA_NO_NODE. [[email protected]: use NUMA_NO_NODE in kthread_create() also] Cc: Nathan Zimmer <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Eric Dumazet <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
CamonZ · Sep 4, 2015 · e9f0698 · e9f0698
1 parent 0469785
commit e9f0698
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Showing 2 changed files with 5 additions and 4 deletions.
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
@@ -11,7 +11,7 @@ struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
 					   const char namefmt[], ...);
 
 #define kthread_create(threadfn, data, namefmt, arg...) \
-	kthread_create_on_node(threadfn, data, -1, namefmt, ##arg)
+	kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
 
 
 struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),

diff --git a/kernel/kthread.c b/kernel/kthread.c
@@ -248,15 +248,16 @@ static void create_kthread(struct kthread_create_info *create)
  * kthread_create_on_node - create a kthread.
  * @threadfn: the function to run until signal_pending(current).
  * @data: data ptr for @threadfn.
- * @node: memory node number.
+ * @node: task and thread structures for the thread are allocated on this node
  * @namefmt: printf-style name for the thread.
  *
  * Description: This helper function creates and names a kernel
  * thread.  The thread will be stopped: use wake_up_process() to start
- * it.  See also kthread_run().
+ * it.  See also kthread_run().  The new thread has SCHED_NORMAL policy and
+ * is affine to all CPUs.
  *
  * If thread is going to be bound on a particular cpu, give its node
- * in @node, to get NUMA affinity for kthread stack, or else give -1.
+ * in @node, to get NUMA affinity for kthread stack, or else give NUMA_NO_NODE.
  * When woken, the thread will run @threadfn() with @data as its
  * argument. @threadfn() can either call do_exit() directly if it is a
  * standalone thread for which no one will call kthread_stop(), or