Re: [PATCH] workqueue: Allocate the unbound pool using local node memory

From: Hillf Danton
Date: Fri Oct 09 2015 - 06:05:44 EST


> From: Xunlei Pang <pang.xunlei@xxxxxxxxxx>
>
> Currently, get_unbound_pool() uses kzalloc() to allocate the
> worker pool. Actually, we can use the right node to do the
> allocation, achieving local memory access.
>
> This patch selects target node first, and uses kzalloc_node()
> instead.
>
> Signed-off-by: Xunlei Pang <pang.xunlei@xxxxxxxxxx>
> ---
> kernel/workqueue.c | 26 ++++++++++++++------------
> 1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index ca71582..96d3747 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -3199,6 +3199,7 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
> u32 hash = wqattrs_hash(attrs);
> struct worker_pool *pool;
> int node;
> + int target_node = NUMA_NO_NODE;
>
> lockdep_assert_held(&wq_pool_mutex);
>
> @@ -3210,13 +3211,25 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
> }
> }
>
> + /* if cpumask is contained inside a NUMA node, we belong to that node */
> + if (wq_numa_enabled) {
> + for_each_node(node) {
> + if (cpumask_subset(attrs->cpumask,
> + wq_numa_possible_cpumask[node])) {
> + target_node = node;
> + break;
> + }
> + }
> + }
> +
> /* nope, create a new one */
> - pool = kzalloc(sizeof(*pool), GFP_KERNEL);
> + pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, target_node);

What if target_node is short of pages at the moment?

> if (!pool || init_worker_pool(pool) < 0)
> goto fail;
>
> lockdep_set_subclass(&pool->lock, 1); /* see put_pwq() */
> copy_workqueue_attrs(pool->attrs, attrs);
> + pool->node = target_node;
>
> /*
> * no_numa isn't a worker_pool attribute, always clear it. See
> @@ -3224,17 +3237,6 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
> */
> pool->attrs->no_numa = false;
>
> - /* if cpumask is contained inside a NUMA node, we belong to that node */
> - if (wq_numa_enabled) {
> - for_each_node(node) {
> - if (cpumask_subset(pool->attrs->cpumask,
> - wq_numa_possible_cpumask[node])) {
> - pool->node = node;
> - break;
> - }
> - }
> - }
> -
> if (worker_pool_assign_id(pool) < 0)
> goto fail;
>
> --
> 1.9.1

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