path: root/block/genhd.c
diff options
authorMing Lei <>2021-12-03 21:15:32 +0800
committerJens Axboe <>2021-12-03 14:51:29 -0700
commit704b914f15fb7daaf517e3acc4bed472b50ca19e (patch)
tree5fffc1140fef4ddceeaae58e44fbb65333c33861 /block/genhd.c
parent2a904d00855f94cb85751e45fa494f225d44ae0d (diff)
blk-mq: move srcu from blk_mq_hw_ctx to request_queue
In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch critical area. However, this srcu instance stays at the end of hctx, and it often takes standalone cacheline, often cold. Inside srcu_read_lock() and srcu_read_unlock(), WRITE is always done on the indirect percpu variable which is allocated from heap instead of being embedded, srcu->srcu_idx is read only in srcu_read_lock(). It doesn't matter if srcu structure stays in hctx or request queue. So switch to per-request-queue srcu for protecting dispatch, and this way simplifies quiesce a lot, not mention quiesce is always done on the request queue wide. Signed-off-by: Ming Lei <> Link: Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block/genhd.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 5179a4f00fba..3c139a1b6f04 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1338,7 +1338,7 @@ struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
struct request_queue *q;
struct gendisk *disk;
- q = blk_alloc_queue(node);
+ q = blk_alloc_queue(node, false);
if (!q)
return NULL;