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authorJens Axboe <axboe@kernel.dk>2018-10-29 22:13:29 +0300
committerJens Axboe <axboe@kernel.dk>2018-11-07 23:44:59 +0300
commitf31967f0e455d08d3ea1d2f849bf62dafc92dbf4 (patch)
tree22fbc79b5ba286e2add8f995a8cfa9f211200192 /block
parentf9afca4d367b8c915f28d29fcaba7460640403ff (diff)
downloadlinux-f31967f0e455d08d3ea1d2f849bf62dafc92dbf4.tar.xz
blk-mq: allow software queue to map to multiple hardware queues
The mapping used to be dependent on just the CPU location, but now it's a tuple of (type, cpu) instead. This is a prep patch for allowing a single software queue to map to multiple hardware queues. No functional changes in this patch. This changes the software queue count to an unsigned short to save a bit of space. We can still support 64K-1 CPUs, which should be enough. Add a check to catch a wrap. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq-sched.c2
-rw-r--r--block/blk-mq.c22
-rw-r--r--block/blk-mq.h2
-rw-r--r--block/kyber-iosched.c6
4 files changed, 21 insertions, 11 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 68087bf71a61..bbabc3877d5a 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -109,7 +109,7 @@ static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
- unsigned idx = ctx->index_hw;
+ unsigned short idx = ctx->index_hw[hctx->type];
if (++idx == hctx->nr_ctx)
idx = 0;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 67dec64440dd..31976bff8ad2 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -75,14 +75,18 @@ static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
- if (!sbitmap_test_bit(&hctx->ctx_map, ctx->index_hw))
- sbitmap_set_bit(&hctx->ctx_map, ctx->index_hw);
+ const int bit = ctx->index_hw[hctx->type];
+
+ if (!sbitmap_test_bit(&hctx->ctx_map, bit))
+ sbitmap_set_bit(&hctx->ctx_map, bit);
}
static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx)
{
- sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
+ const int bit = ctx->index_hw[hctx->type];
+
+ sbitmap_clear_bit(&hctx->ctx_map, bit);
}
struct mq_inflight {
@@ -955,7 +959,7 @@ static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *start)
{
- unsigned off = start ? start->index_hw : 0;
+ unsigned off = start ? start->index_hw[hctx->type] : 0;
struct dispatch_rq_data data = {
.hctx = hctx,
.rq = NULL,
@@ -2343,10 +2347,16 @@ static void blk_mq_map_swqueue(struct request_queue *q)
ctx = per_cpu_ptr(q->queue_ctx, i);
hctx = blk_mq_map_queue_type(q, 0, i);
-
+ hctx->type = 0;
cpumask_set_cpu(i, hctx->cpumask);
- ctx->index_hw = hctx->nr_ctx;
+ ctx->index_hw[hctx->type] = hctx->nr_ctx;
hctx->ctxs[hctx->nr_ctx++] = ctx;
+
+ /*
+ * If the nr_ctx type overflows, we have exceeded the
+ * amount of sw queues we can support.
+ */
+ BUG_ON(!hctx->nr_ctx);
}
mutex_unlock(&q->sysfs_lock);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 6a8f8b60d8ba..1821f448f7c4 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -17,7 +17,7 @@ struct blk_mq_ctx {
} ____cacheline_aligned_in_smp;
unsigned int cpu;
- unsigned int index_hw;
+ unsigned short index_hw[HCTX_MAX_TYPES];
/* incremented at dispatch time */
unsigned long rq_dispatched[2];
diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index 1fd83a91e749..de78e8aa7b0a 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -576,7 +576,7 @@ static bool kyber_bio_merge(struct blk_mq_hw_ctx *hctx, struct bio *bio)
{
struct kyber_hctx_data *khd = hctx->sched_data;
struct blk_mq_ctx *ctx = blk_mq_get_ctx(hctx->queue);
- struct kyber_ctx_queue *kcq = &khd->kcqs[ctx->index_hw];
+ struct kyber_ctx_queue *kcq = &khd->kcqs[ctx->index_hw[hctx->type]];
unsigned int sched_domain = kyber_sched_domain(bio->bi_opf);
struct list_head *rq_list = &kcq->rq_list[sched_domain];
bool merged;
@@ -602,7 +602,7 @@ static void kyber_insert_requests(struct blk_mq_hw_ctx *hctx,
list_for_each_entry_safe(rq, next, rq_list, queuelist) {
unsigned int sched_domain = kyber_sched_domain(rq->cmd_flags);
- struct kyber_ctx_queue *kcq = &khd->kcqs[rq->mq_ctx->index_hw];
+ struct kyber_ctx_queue *kcq = &khd->kcqs[rq->mq_ctx->index_hw[hctx->type]];
struct list_head *head = &kcq->rq_list[sched_domain];
spin_lock(&kcq->lock);
@@ -611,7 +611,7 @@ static void kyber_insert_requests(struct blk_mq_hw_ctx *hctx,
else
list_move_tail(&rq->queuelist, head);
sbitmap_set_bit(&khd->kcq_map[sched_domain],
- rq->mq_ctx->index_hw);
+ rq->mq_ctx->index_hw[hctx->type]);
blk_mq_sched_request_inserted(rq);
spin_unlock(&kcq->lock);
}