Commit 81c98869 authored Apr 03, 2014 by Nishanth Aravamudan Committed by Linus Torvalds Apr 03, 2014

kthread: ensure locality of task_struct allocations



In the presence of memoryless nodes, numa_node_id() will return the
current CPU's NUMA node, but that may not be where we expect to allocate
from memory from.  Instead, we should rely on the fallback code in the
memory allocator itself, by using NUMA_NO_NODE.  Also, when calling
kthread_create_on_node(), use the nearest node with memory to the cpu in
question, rather than the node it is running on.

Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 5acda9d1

kernel/kthread.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -217,7 +217,7 @@ int tsk_fork_get_node(struct task_struct *tsk)
		if (tsk == kthreadd_task)
		return tsk->pref_node_fork;
		#endif
		return numa_node_id();
		return NUMA_NO_NODE;
		}

		static void create_kthread(struct kthread_create_info *create)
		@@ -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_node(cpu), namefmt,
		p = kthread_create_on_node(threadfn, data, cpu_to_mem(cpu), namefmt,
		cpu);
		if (IS_ERR(p))
		return p;