[PATCH] blk-mq: remove the calling of local_memory_node()

From: Xianting Tian
Date: Mon Oct 19 2020 - 04:31:12 EST


We don't need to check whether the node is memoryless numa node before
calling allocator interface. SLUB(and SLAB,SLOB) relies on the page
allocator to pick a node. Page allocator should deal with memoryless
nodes just fine. It has zonelists constructed for each possible nodes.
And it will automatically fall back into a node which is closest to the
requested node. As long as __GFP_THISNODE is not enforced of course.

The code comments of kmem_cache_alloc_node() of SLAB also showed this:
* Fallback to other node is possible if __GFP_THISNODE is not set.

blk-mq code doesn't set __GFP_THISNODE, so we can remove the calling
of local_memory_node().

Fixes: bffed457160ab ("blk-mq: Avoid memoryless numa node encoded in hctx numa_node")

Signed-off-by: Xianting Tian <tian.xianting@xxxxxxx>
---
block/blk-mq-cpumap.c | 2 +-
block/blk-mq.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c
index 0157f2b34..3db84d319 100644
--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c
@@ -89,7 +89,7 @@ int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)

for_each_possible_cpu(i) {
if (index == qmap->mq_map[i])
- return local_memory_node(cpu_to_node(i));
+ return cpu_to_node(i);
}

return NUMA_NO_NODE;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index cdced4aca..48f8366b2 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2737,7 +2737,7 @@ static void blk_mq_init_cpu_queues(struct request_queue *q,
for (j = 0; j < set->nr_maps; j++) {
hctx = blk_mq_map_queue_type(q, j, i);
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
- hctx->numa_node = local_memory_node(cpu_to_node(i));
+ hctx->numa_node = cpu_to_node(i);
}
}
}
--
2.17.1