From fc1bc35443741e132dd0118e8dbac53f69a6f76e Mon Sep 17 00:00:00 2001 From: Matias Bjørling Date: Sat, 21 Dec 2013 00:11:01 +0100 Subject: null_blk: support submit_queues on use_per_node_hctx In the case of both the submit_queues param and use_per_node_hctx param are used. We limit the number af submit_queues to the number of online nodes. If the submit_queues is a multiple of nr_online_nodes, its trivial. Simply map them to the nodes. For example: 8 submit queues are mapped as node0[0,1], node1[2,3], ... If uneven, we are left with an uneven number of submit_queues that must be mapped. These are mapped toward the first node and onward. E.g. 5 submit queues mapped onto 4 nodes are mapped as node0[0,1], node1[2], ... Signed-off-by: Matias Bjorling Signed-off-by: Jens Axboe --- drivers/block/null_blk.c | 39 +++++++++++++++++++++++++++++++++++---- 1 file changed, 35 insertions(+), 4 deletions(-) diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c index 9b0311b61fe..528f4e47f38 100644 --- a/drivers/block/null_blk.c +++ b/drivers/block/null_blk.c @@ -1,4 +1,5 @@ #include + #include #include #include @@ -346,8 +347,37 @@ static int null_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq) static struct blk_mq_hw_ctx *null_alloc_hctx(struct blk_mq_reg *reg, unsigned int hctx_index) { - return kzalloc_node(sizeof(struct blk_mq_hw_ctx), GFP_KERNEL, - hctx_index); + int b_size = DIV_ROUND_UP(reg->nr_hw_queues, nr_online_nodes); + int tip = (reg->nr_hw_queues % nr_online_nodes); + int node = 0, i, n; + + /* + * Split submit queues evenly wrt to the number of nodes. If uneven, + * fill the first buckets with one extra, until the rest is filled with + * no extra. + */ + for (i = 0, n = 1; i < hctx_index; i++, n++) { + if (n % b_size == 0) { + n = 0; + node++; + + tip--; + if (!tip) + b_size = reg->nr_hw_queues / nr_online_nodes; + } + } + + /* + * A node might not be online, therefore map the relative node id to the + * real node id. + */ + for_each_online_node(n) { + if (!node) + break; + node--; + } + + return kzalloc_node(sizeof(struct blk_mq_hw_ctx), GFP_KERNEL, n); } static void null_free_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_index) @@ -591,10 +621,11 @@ static int __init null_init(void) #endif if (queue_mode == NULL_Q_MQ && use_per_node_hctx) { - if (submit_queues > 0) + if (submit_queues < nr_online_nodes) { pr_warn("null_blk: submit_queues param is set to %u.", nr_online_nodes); - submit_queues = nr_online_nodes; + submit_queues = nr_online_nodes; + } } else if (submit_queues > nr_cpu_ids) submit_queues = nr_cpu_ids; else if (!submit_queues) -- cgit v1.2.3-18-g5258