Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755406AbaA1SiV (ORCPT ); Tue, 28 Jan 2014 13:38:21 -0500 Received: from e39.co.us.ibm.com ([32.97.110.160]:56697 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754866AbaA1SiU (ORCPT ); Tue, 28 Jan 2014 13:38:20 -0500 Date: Tue, 28 Jan 2014 10:38:08 -0800 From: Nishanth Aravamudan To: LKML Cc: Anton Blanchard , Christoph Lameter , Andrew Morton , Tejun Heo , Oleg Nesterov , Jan Kara , David Rientjes , Thomas Gleixner , Tetsuo Handa , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Wanpeng Li , Joonsoo Kim , Ben Herrenschmidt Subject: [PATCH] kthread: ensure locality of task_struct allocations Message-ID: <20140128183808.GB9315@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Operating-System: Linux 3.11.0-15-generic (x86_64) User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14012818-9332-0000-0000-000002EA4945 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the presence of memoryless nodes, numa_node_id()/cpu_to_node() will return the current CPU's NUMA node, but that may not be where we expect to allocate from memory from. Instead, we should use numa_mem_id()/cpu_to_mem(). On one ppc64 system with a memoryless Node 0, this ends up saving nearly 500M of slab due to less fragmentation. Signed-off-by: Nishanth Aravamudan diff --git a/kernel/kthread.c b/kernel/kthread.c index b5ae3ee..8573e4e 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -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_mem_id(); } 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/