This is 2nd step change in a bid to enable mapping of multiple
device hardware queues to a single CPU.
It enables number of tags assigned to a hardware context to exceed
the device hardware queue depth. As result single hardware context
could be mapped to multiple low-level hardware contexts. This is a
prerequisite to introduce combined hardware contexts.
CC: Jens Axboe <ax...@kernel.dk>
CC: linux-n...@lists.infradead.org
Signed-off-by: Alexander Gordeev <agord...@redhat.com>
---
block/blk-core.c | 4 +++-
block/blk-mq.c | 9 +++++++--
include/linux/blk-mq.h | 7 +++++++
3 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index bf4f196..36ae127 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3312,9 +3312,11 @@ bool blk_poll(struct request_queue *q, blk_qc_t cookie)
state = current->state;
while (!need_resched()) {
+ unsigned int tag = blk_qc_t_to_tag(cookie);
unsigned int queue_num = blk_qc_t_to_queue_num(cookie);
struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[queue_num];
- struct blk_mq_llhw_ctx *llhw_ctx = &hctx->llhw_ctxs[0];
+ int idx = blk_mq_tag_to_llhw_ctx_idx(hctx, tag);
+ struct blk_mq_llhw_ctx *llhw_ctx = &hctx->llhw_ctxs[idx];
int ret;
hctx->poll_invoked++;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 274eab8..6d055ec 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -829,6 +829,7 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx)
queued = 0;
while (!list_empty(&rq_list)) {
struct blk_mq_queue_data bd;
+ int llhw_ctx_idx;
int ret;
rq = list_first_entry(&rq_list, struct request, queuelist);
@@ -838,7 +839,9 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx)
bd.list = dptr;
bd.last = list_empty(&rq_list);
- ret = q->mq_ops->queue_rq(&hctx->llhw_ctxs[0], &bd);
+ llhw_ctx_idx = blk_mq_tag_to_llhw_ctx_idx(hctx, rq->tag);
+
+ ret = q->mq_ops->queue_rq(&hctx->llhw_ctxs[llhw_ctx_idx], &bd);
switch (ret) {
case BLK_MQ_RQ_QUEUE_OK:
queued++;
@@ -1260,13 +1263,14 @@ static int blk_mq_direct_issue_request(struct request
*rq, blk_qc_t *cookie)
.last = 1
};
blk_qc_t new_cookie = blk_tag_to_qc_t(rq->tag, hctx->queue_num);
+ int llhw_ctx_idx = blk_mq_tag_to_llhw_ctx_idx(hctx, rq->tag);
/*
* For OK queue, we are done. For error, kill it. Any other
* error (busy), just add it to our list as we previously
* would have done
*/
- ret = q->mq_ops->queue_rq(&hctx->llhw_ctxs[0], &bd);
+ ret = q->mq_ops->queue_rq(&hctx->llhw_ctxs[llhw_ctx_idx], &bd);
if (ret == BLK_MQ_RQ_QUEUE_OK) {
*cookie = new_cookie;
return 0;
@@ -1741,6 +1745,7 @@ static struct blk_mq_hw_ctx *blk_mq_init_hctx(struct
request_queue *q,
hctx->queue_num = hctx_idx;
hctx->nr_ctx = 0;
hctx->nr_llhw_ctx = nr_llhw_ctx;
+ hctx->llhw_queue_depth = set->queue_depth;
hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED;
hctx->tags = set->tags[hctx_idx];
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 2c3392b..52a9e7c 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -67,6 +67,7 @@ struct blk_mq_hw_ctx {
unsigned long poll_invoked;
unsigned long poll_success;
+ unsigned int llhw_queue_depth;
unsigned int nr_llhw_ctx;
struct blk_mq_llhw_ctx llhw_ctxs[0];
};
@@ -79,6 +80,12 @@ struct blk_mq_hw_ctx *blk_mq_to_hctx(struct blk_mq_llhw_ctx
*llhw_ctx)
return (void *)llhw_ctx_0 - offsetof(struct blk_mq_hw_ctx, llhw_ctxs);
}
+static inline
+int blk_mq_tag_to_llhw_ctx_idx(struct blk_mq_hw_ctx *hctx, unsigned int tag)
+{
+ return tag / hctx->llhw_queue_depth;
+}
+
struct blk_mq_tag_set {
struct blk_mq_ops *ops;
unsigned int nr_hw_queues;
--
1.8.3.1
