diff options
| -rw-r--r-- | block/blk-flush.c | 8 | ||||
| -rw-r--r-- | block/blk-mq.c | 46 | ||||
| -rw-r--r-- | include/linux/blk-mq.h | 3 |
3 files changed, 38 insertions, 19 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c index 9288aaf..9143e85 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -284,9 +284,8 @@ static void mq_flush_work(struct work_struct *work) q = container_of(work, struct request_queue, mq_flush_work); - /* We don't need set REQ_FLUSH_SEQ, it's for consistency */ rq = blk_mq_alloc_request(q, WRITE_FLUSH|REQ_FLUSH_SEQ, - __GFP_WAIT|GFP_ATOMIC, true); + __GFP_WAIT|GFP_ATOMIC, false); rq->cmd_type = REQ_TYPE_FS; rq->end_io = flush_end_io; @@ -408,8 +407,11 @@ void blk_insert_flush(struct request *rq) /* * @policy now records what operations need to be done. Adjust * REQ_FLUSH and FUA for the driver. + * We keep REQ_FLUSH for mq to track flush requests. For !FUA, + * we never dispatch the request directly. */ - rq->cmd_flags &= ~REQ_FLUSH; + if (rq->cmd_flags & REQ_FUA) + rq->cmd_flags &= ~REQ_FLUSH; if (!(fflags & REQ_FUA)) rq->cmd_flags &= ~REQ_FUA; diff --git a/block/blk-mq.c b/block/blk-mq.c index 57039fc..9072d0a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -194,9 +194,27 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx, } static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx, - gfp_t gfp, bool reserved) + gfp_t gfp, bool reserved, + int rw) { - return blk_mq_alloc_rq(hctx, gfp, reserved); + struct request *req; + bool is_flush = false; + /* + * flush need allocate a request, leave at least one request for + * non-flush IO to avoid deadlock + */ + if ((rw & REQ_FLUSH) && !(rw & REQ_FLUSH_SEQ)) { + if (atomic_inc_return(&hctx->pending_flush) >= + hctx->queue_depth - hctx->reserved_tags - 1) { + atomic_dec(&hctx->pending_flush); + return NULL; + } + is_flush = true; + } + req = blk_mq_alloc_rq(hctx, gfp, reserved); + if (!req && is_flush) + atomic_dec(&hctx->pending_flush); + return req; } static struct request *blk_mq_alloc_request_pinned(struct request_queue *q, @@ -209,7 +227,7 @@ static struct request *blk_mq_alloc_request_pinned(struct request_queue *q, struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); struct blk_mq_hw_ctx *hctx = q->mq_ops->map_queue(q, ctx->cpu); - rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved); + rq = __blk_mq_alloc_request(hctx, gfp & ~__GFP_WAIT, reserved, rw); if (rq) { blk_mq_rq_ctx_init(q, ctx, rq, rw); break; @@ -272,6 +290,9 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, const int tag = rq->tag; struct request_queue *q = rq->q; + if ((rq->cmd_flags & REQ_FLUSH) && !(rq->cmd_flags & REQ_FLUSH_SEQ)) + atomic_dec(&hctx->pending_flush); + blk_mq_rq_init(hctx, rq); blk_mq_put_tag(hctx->tags, tag); @@ -900,14 +921,14 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio) hctx = q->mq_ops->map_queue(q, ctx->cpu); trace_block_getrq(q, bio, rw); - rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false); + rq = __blk_mq_alloc_request(hctx, GFP_ATOMIC, false, bio->bi_rw); if (likely(rq)) - blk_mq_rq_ctx_init(q, ctx, rq, rw); + blk_mq_rq_ctx_init(q, ctx, rq, bio->bi_rw); else { blk_mq_put_ctx(ctx); trace_block_sleeprq(q, bio, rw); - rq = blk_mq_alloc_request_pinned(q, rw, __GFP_WAIT|GFP_ATOMIC, - false); + rq = blk_mq_alloc_request_pinned(q, bio->bi_rw, + __GFP_WAIT|GFP_ATOMIC, false); ctx = rq->mq_ctx; hctx = q->mq_ops->map_queue(q, ctx->cpu); } @@ -1184,7 +1205,9 @@ static int blk_mq_init_hw_queues(struct request_queue *q, hctx->queue_num = i; hctx->flags = reg->flags; hctx->queue_depth = reg->queue_depth; + hctx->reserved_tags = reg->reserved_tags; hctx->cmd_size = reg->cmd_size; + atomic_set(&hctx->pending_flush, 0); blk_mq_init_cpu_notifier(&hctx->cpu_notifier, blk_mq_hctx_notify, hctx); @@ -1309,15 +1332,6 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg, reg->queue_depth = BLK_MQ_MAX_DEPTH; } - /* - * Set aside a tag for flush requests. It will only be used while - * another flush request is in progress but outside the driver. - * - * TODO: only allocate if flushes are supported - */ - reg->queue_depth++; - reg->reserved_tags++; - if (reg->queue_depth < (reg->reserved_tags + BLK_MQ_TAG_MIN)) return ERR_PTR(-EINVAL); diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 161b231..1e8f16f 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -36,12 +36,15 @@ struct blk_mq_hw_ctx { struct list_head page_list; struct blk_mq_tags *tags; + atomic_t pending_flush; + unsigned long queued; unsigned long run; #define BLK_MQ_MAX_DISPATCH_ORDER 10 unsigned long dispatched[BLK_MQ_MAX_DISPATCH_ORDER]; unsigned int queue_depth; + unsigned int reserved_tags; unsigned int numa_node; unsigned int cmd_size; /* per-request extra data */ |
