diff options
| author |   John Garry <john.garry@huawei.com> | 2021-10-05 18:23:37 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2021-10-18 06:17:03 -0600 |
| commit | e155b0c238b20f0a866f4334d292656665836c8a (patch) | |
| tree | b15573dfa9eb29747802e2ba407d1e0381ca66d8 /block/blk-mq-tag.h | |
| parent | blk-mq: Refactor and rename blk_mq_free_map_and_{requests->rqs}() (diff) | |
| download | linux-dev-e155b0c238b20f0a866f4334d292656665836c8a.tar.xz linux-dev-e155b0c238b20f0a866f4334d292656665836c8a.zip | |
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 <john.garry@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1633429419-228500-13-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq-tag.h')
| -rw-r--r-- | block/blk-mq-tag.h | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h index a9f5f1824819..e43f7589b96c 100644 --- a/block/blk-mq-tag.h +++ b/block/blk-mq-tag.h @@ -32,16 +32,14 @@ struct blk_mq_tags { extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, - int node, unsigned int flags); -extern void blk_mq_free_tags(struct blk_mq_tags *tags, unsigned int flags); + int node, int alloc_policy); +extern void blk_mq_free_tags(struct blk_mq_tags *tags); extern int blk_mq_init_bitmaps(struct sbitmap_queue *bitmap_tags, struct sbitmap_queue *breserved_tags, unsigned int queue_depth, unsigned int reserved, int node, int alloc_policy); -extern int blk_mq_init_shared_sbitmap(struct blk_mq_tag_set *set); -extern void blk_mq_exit_shared_sbitmap(struct blk_mq_tag_set *set); extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data); extern void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx, unsigned int tag); |