Do not update nr_hw_queues again after setting it to 1 for a kdump kernel. This avoids allocating a tag set of size nr_cpu_ids and but then just using one tag set.
Signed-off-by: Daniel Wagner <[email protected]> --- Hi, I stumbled across this and didn't make sense to me that we might allocated more tag sets than we potently use. But maybe I am not seeing the obvious thing. Only compiled tested. Thanks, Daniel block/blk-mq.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 4f57d27bfa73..e32cb0217135 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -3291,13 +3291,14 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) set->nr_hw_queues = 1; set->nr_maps = 1; set->queue_depth = min(64U, set->queue_depth); + } else { + /* + * There is no use for more h/w queues than cpus + * if we just have a single map + */ + if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids) + set->nr_hw_queues = nr_cpu_ids; } - /* - * There is no use for more h/w queues than cpus if we just have - * a single map - */ - if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids) - set->nr_hw_queues = nr_cpu_ids; if (blk_mq_realloc_tag_set_tags(set, 0, set->nr_hw_queues) < 0) return -ENOMEM; @@ -3309,7 +3310,7 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) GFP_KERNEL, set->numa_node); if (!set->map[i].mq_map) goto out_free_mq_map; - set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues; + set->map[i].nr_queues = set->nr_hw_queues; } ret = blk_mq_update_queue_map(set); -- 2.16.4
