[RFC 1/2] workqueue: use the nearest NUMA node, not the local one
From: Nishanth Aravamudan <hidden>
Date: 2014-07-17 23:10:12
Also in:
linux-mm, lkml
Subsystem:
the rest, workqueue · Maintainers:
Linus Torvalds, Tejun Heo
In the presence of memoryless nodes, the workqueue code incorrectly uses cpu_to_node() to determine what node to prefer memory allocations come from. cpu_to_mem() should be used instead, which will use the nearest NUMA node with memory. Signed-off-by: Nishanth Aravamudan <redacted>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 35974ac..0bba022 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c@@ -3547,7 +3547,12 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs) for_each_node(node) { if (cpumask_subset(pool->attrs->cpumask, wq_numa_possible_cpumask[node])) { - pool->node = node; + /* + * We could use local_memory_node(node) here, + * but it is expensive and the following caches + * the same value. + */ + pool->node = cpu_to_mem(cpumask_first(pool->attrs->cpumask)); break; } }
@@ -4921,7 +4926,7 @@ static int __init init_workqueues(void) pool->cpu = cpu; cpumask_copy(pool->attrs->cpumask, cpumask_of(cpu)); pool->attrs->nice = std_nice[i++]; - pool->node = cpu_to_node(cpu); + pool->node = cpu_to_mem(cpu); /* alloc pool ID */ mutex_lock(&wq_pool_mutex);