blk-mq: move the kdump check to blk_mq_alloc_tag_set

We call blk_mq_alloc_tag_set() first then blk_mq_init_queue(). The requests are
allocated in the former function. So the kdump check should be moved to there
to really save memory.

Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 27a347fe8f5b..4854e709aa34 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1804,16 +1804,6 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
         if (!ctx)
                 return ERR_PTR(-ENOMEM);
 
-        /*
-         * If a crashdump is active, then we are potentially in a very
-         * memory constrained environment. Limit us to 1 queue and
-         * 64 tags to prevent using too much memory.
-         */
-        if (is_kdump_kernel()) {
-                set->nr_hw_queues = 1;
-                set->queue_depth = min(64U, set->queue_depth);
-        }
-
         hctxs = kmalloc_node(set->nr_hw_queues * sizeof(*hctxs), GFP_KERNEL,
                         set->numa_node);
 
@@ -2070,6 +2060,16 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
                 set->queue_depth = BLK_MQ_MAX_DEPTH;
         }
 
+        /*
+         * If a crashdump is active, then we are potentially in a very
+         * memory constrained environment. Limit us to 1 queue and
+         * 64 tags to prevent using too much memory.
+         */
+        if (is_kdump_kernel()) {
+                set->nr_hw_queues = 1;
+                set->queue_depth = min(64U, set->queue_depth);
+        }
+
         set->tags = kmalloc_node(set->nr_hw_queues *
                                  sizeof(struct blk_mq_tags *),
                                  GFP_KERNEL, set->numa_node);