From: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Anton Blanchard <anton@samba.org>,
Christoph Lameter <cl@linux.com>,
Andrew Morton <akpm@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Oleg Nesterov <oleg@redhat.com>,
Jan Kara <jack@suse.cz>, David Rientjes <rientjes@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Wanpeng Li <liwanp@linux.vnet.ibm.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Ben Herrenschmidt <benh@kernel.crashing.org>
Subject: [PATCH] kthread: ensure locality of task_struct allocations
Date: Tue, 28 Jan 2014 10:38:08 -0800 [thread overview]
Message-ID: <20140128183808.GB9315@linux.vnet.ibm.com> (raw)
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 <nacc@linux.vnet.ibm.com>
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;
next reply other threads:[~2014-01-28 18:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-28 18:38 Nishanth Aravamudan [this message]
2014-01-29 8:13 ` [PATCH] kthread: ensure locality of task_struct allocations David Rientjes
2014-01-29 15:58 ` Christoph Lameter
2014-01-30 0:27 ` David Rientjes
2014-01-30 6:14 ` Eric Dumazet
2014-01-30 22:47 ` David Rientjes
2014-01-30 23:08 ` Nishanth Aravamudan
2014-01-30 23:31 ` David Rientjes
2014-01-31 15:14 ` Christoph Lameter
2014-01-29 15:57 ` Christoph Lameter
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