From 4f266f2be822eacd70aca2a7a53c4a111be79acb Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Mon, 18 Oct 2021 21:37:27 +0100 Subject: [PATCH] block: skip elevator fields init for non-elv queue Don't init rq->hash and rq->rb_node in blk_mq_rq_ctx_init() if there is no elevator. Also, move some other initialisers that imply barriers to the end, so the compiler is free to rearrange and optimise other the rest of them. note: fold in a change from Jens leaving queue_list unconditional, as it might lead to problems otherwise. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- block/blk-mq.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 28eb1f3c6f76..1d2e2fd4043e 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -325,6 +325,10 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, rq->internal_tag = BLK_MQ_NO_TAG; } + if (blk_mq_need_time_stamp(rq)) + rq->start_time_ns = ktime_get_ns(); + else + rq->start_time_ns = 0; /* csd/requeue_work/fifo_time is initialized before use */ rq->q = data->q; rq->mq_ctx = data->ctx; @@ -334,41 +338,37 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, rq->rq_flags |= RQF_PM; if (blk_queue_io_stat(data->q)) rq->rq_flags |= RQF_IO_STAT; - INIT_LIST_HEAD(&rq->queuelist); - INIT_HLIST_NODE(&rq->hash); - RB_CLEAR_NODE(&rq->rb_node); rq->rq_disk = NULL; rq->part = NULL; #ifdef CONFIG_BLK_RQ_ALLOC_TIME rq->alloc_time_ns = alloc_time_ns; #endif - if (blk_mq_need_time_stamp(rq)) - rq->start_time_ns = ktime_get_ns(); - else - rq->start_time_ns = 0; rq->io_start_time_ns = 0; rq->stats_sectors = 0; rq->nr_phys_segments = 0; #if defined(CONFIG_BLK_DEV_INTEGRITY) rq->nr_integrity_segments = 0; #endif - blk_crypto_rq_set_defaults(rq); - /* tag was already set */ - WRITE_ONCE(rq->deadline, 0); - rq->timeout = 0; - rq->end_io = NULL; rq->end_io_data = NULL; data->ctx->rq_dispatched[op_is_sync(data->cmd_flags)]++; + blk_crypto_rq_set_defaults(rq); + INIT_LIST_HEAD(&rq->queuelist); + /* tag was already set */ + WRITE_ONCE(rq->deadline, 0); refcount_set(&rq->ref, 1); - if (!op_is_flush(data->cmd_flags) && (rq->rq_flags & RQF_ELV)) { + if (rq->rq_flags & RQF_ELV) { struct elevator_queue *e = data->q->elevator; rq->elv.icq = NULL; - if (e->type->ops.prepare_request) { + INIT_HLIST_NODE(&rq->hash); + RB_CLEAR_NODE(&rq->rb_node); + + if (!op_is_flush(data->cmd_flags) && + e->type->ops.prepare_request) { if (e->type->icq_cache) blk_mq_sched_assign_ioc(rq); -- 2.11.0