[RFC PATCH 3/4] Partial revert of 81c98869faa5 ("kthread: ensure locality of task_struct allocations")

[Nishanth Aravamudan <nacc@linux.vnet.ibm.com>]

After discussions with Tejun, we don't want to spread the use of
cpu_to_mem() (and thus knowledge of allocators/NUMA topology details)
into callers, but would rather ensure the callees correctly handle
memoryless nodes. With the previous patches ("topology: add support for
node_to_mem_node() to determine the fallback node" and "slub: fallback
to node_to_mem_node() node if allocating on memoryless node") adding and
using node_to_mem_node(), we can safely undo part of the change to the
kthread logic from 81c98869faa5 ("kthread: ensure locality of
task_struct allocations").
    
Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>

diff --git a/kernel/kthread.c b/kernel/kthread.c
index ef483220e855..10e489c448fe 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -369,7 +369,7 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
 {
 	struct task_struct *p;
 
-	p = kthread_create_on_node(threadfn, data, cpu_to_mem(cpu), namefmt,
+	p = kthread_create_on_node(threadfn, data, cpu_to_node(cpu), namefmt,
 				   cpu);
 	if (IS_ERR(p))
 		return p;