[PATCH V3 2/6] blk-mq: simplify reallocation of hw ctxs a bit

Ming Lei
2022-03-07T06:44:47Z

blk_mq_alloc_and_init_hctx() has already taken reuse into account, so
no need to do it outside, then we can simplify blk_mq_realloc_hw_ctxs().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/blk-mq.c | 33 ++++++++++++++-------------------
1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 5d25abf9e551..64fddb36c93c 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -3966,29 +3966,24 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
/* protect against switching io scheduler */
mutex_lock(&q->sysfs_lock);
for (i = 0; i < set->nr_hw_queues; i++) {
+ int old_node;
int node = blk_mq_get_hctx_node(set, i);
- struct blk_mq_hw_ctx *hctx;
+ struct blk_mq_hw_ctx *old_hctx = hctxs[i];

- /*
- * If the hw queue has been mapped to another numa node,
- * we need to realloc the hctx. If allocation fails, fallback
- * to use the previous one.
- */
- if (hctxs[i] && (hctxs[i]->numa_node == node))
- continue;
+ if (old_hctx) {
+ old_node = old_hctx->numa_node;
+ blk_mq_exit_hctx(q, set, old_hctx, i);
+ }

- hctx = blk_mq_alloc_and_init_hctx(set, q, i, node);
- if (hctx) {
- if (hctxs[i])
- blk_mq_exit_hctx(q, set, hctxs[i], i);
- hctxs[i] = hctx;
- } else {
- if (hctxs[i])
- pr_warn("Allocate new hctx on node %d fails,\
- fallback to previous one on node %d\n",
- node, hctxs[i]->numa_node);
- else
+ hctxs[i] = blk_mq_alloc_and_init_hctx(set, q, i, node);
+ if (!hctxs[i]) {
+ if (!old_hctx)
break;
+ pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
+ node, old_node);
+ hctxs[i] = blk_mq_alloc_and_init_hctx(set, q, i,
+ old_node);
+ WARN_ON_ONCE(!hctxs[i]);
}
}
/*
--
2.31.1