kthread: NUMA aware kthread_create_on_node()

All kthreads being created from a single helper task, they all use memory
from a single node for their kernel stack and task struct.

This patch suite creates kthread_create_on_node(), adding a 'cpu' parameter
to parameters already used by kthread_create().

This parameter serves in allocating memory for the new kthread on its
memory node if possible.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 11 insertions, 4 deletions

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index 7ff16f7d3ed4..1e923e5e88e8 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -4,10 +4,15 @@
 #include <linux/err.h>
 #include <linux/sched.h>
 
-struct task_struct *kthread_create(int (*threadfn)(void *data),
-                                   void *data,
-                                   const char namefmt[], ...)
-        __attribute__((format(printf, 3, 4)));
+struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
+                                           void *data,
+                                           int node,
+                                           const char namefmt[], ...)
+        __attribute__((format(printf, 4, 5)));
+
+#define kthread_create(threadfn, data, namefmt, arg...) \
+        kthread_create_on_node(threadfn, data, -1, namefmt, ##arg)
+
 
 /**
  * kthread_run - create and wake a thread.
@@ -34,6 +39,7 @@ void *kthread_data(struct task_struct *k);
 
 int kthreadd(void *unused);
 extern struct task_struct *kthreadd_task;
+extern int tsk_fork_get_node(struct task_struct *tsk);
 
 /*
  * Simple work processor based on kthread.
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c15936fe998b..4b601be3dace 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1471,6 +1471,7 @@ struct task_struct {
 #ifdef CONFIG_NUMA
         struct mempolicy *mempolicy;    /* Protected by alloc_lock */
         short il_next;
+        short pref_node_fork;
 #endif
         atomic_t fs_excl;       /* holding fs exclusive resources */
         struct rcu_head rcu;