From e155b0c238b20f0a866f4334d292656665836c8a Mon Sep 17 00:00:00 2001 From: John Garry Date: Tue, 5 Oct 2021 18:23:37 +0800 Subject: blk-mq: Use shared tags for shared sbitmap support Currently we use separate sbitmap pairs and active_queues atomic_t for shared sbitmap support. However a full sets of static requests are used per HW queue, which is quite wasteful, considering that the total number of requests usable at any given time across all HW queues is limited by the shared sbitmap depth. As such, it is considerably more memory efficient in the case of shared sbitmap to allocate a set of static rqs per tag set or request queue, and not per HW queue. So replace the sbitmap pairs and active_queues atomic_t with a shared tags per tagset and request queue, which will hold a set of shared static rqs. Since there is now no valid HW queue index to be passed to the blk_mq_ops .init and .exit_request callbacks, pass an invalid index token. This changes the semantics of the APIs, such that the callback would need to validate the HW queue index before using it. Currently no user of shared sbitmap actually uses the HW queue index (as would be expected). Signed-off-by: John Garry Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/1633429419-228500-13-git-send-email-john.garry@huawei.com Signed-off-by: Jens Axboe --- include/linux/blkdev.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux/blkdev.h') diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 0e960d74615e..cf92c13eb80e 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -238,8 +238,7 @@ struct request_queue { atomic_t nr_active_requests_shared_sbitmap; - struct sbitmap_queue sched_bitmap_tags; - struct sbitmap_queue sched_breserved_tags; + struct blk_mq_tags *shared_sbitmap_tags; struct list_head icq_list; #ifdef CONFIG_BLK_CGROUP -- cgit v1.2.3-59-g8ed1b