From nobody Sun Feb 8 08:22:31 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68B0FEB64D7 for ; Wed, 28 Jun 2023 12:47:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231428AbjF1MrL (ORCPT ); Wed, 28 Jun 2023 08:47:11 -0400 Received: from out-20.mta1.migadu.com ([95.215.58.20]:42890 "EHLO out-20.mta1.migadu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231770AbjF1MqV (ORCPT ); Wed, 28 Jun 2023 08:46:21 -0400 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1687956379; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3XFNAPAH6EuvNrQxjh5kQssWIEiKUAzjh/YE9gXkp8o=; b=ZB6x5iMJqA8fmsPlQ9csKa8eBIPh55rqemfIfNxgnDavPid2FV70CgRteGjoqUMd16rJ1U C/6TTcH8RqjGAph+iWU30iPJEa/lm+izi4ZcSndLvXFhJGOMdzX/kNxaS6plfuUlB2M8HD JfQ5E4WnEkjpfYXg5wEuKqhZD6zApL0= From: chengming.zhou@linux.dev To: axboe@kernel.dk, tj@kernel.org Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, zhouchengming@bytedance.com, ming.lei@redhat.com, hch@lst.de Subject: [PATCH v3 2/3] blk-mq: ktime_get_ns() only once for batched requests init Date: Wed, 28 Jun 2023 20:45:45 +0800 Message-Id: <20230628124546.1056698-3-chengming.zhou@linux.dev> In-Reply-To: <20230628124546.1056698-1-chengming.zhou@linux.dev> References: <20230628124546.1056698-1-chengming.zhou@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Chengming Zhou Extend blk_mq_rq_ctx_init() to receive start_time_ns, so we can ktime_get_ns() only once for batched requests start_time_ns setting. Since data->rq_flags initialization has been moved to the caller __blk_mq_alloc_requests(), we can use it to check if time is needed. Signed-off-by: Chengming Zhou --- block/blk-mq.c | 23 ++++++++++++++--------- include/linux/blk-mq.h | 6 +++--- 2 files changed, 17 insertions(+), 12 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index c50ef953759f..8b981d0a868e 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -338,7 +338,8 @@ void blk_rq_init(struct request_queue *q, struct reques= t *rq) EXPORT_SYMBOL(blk_rq_init); =20 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, - struct blk_mq_tags *tags, unsigned int tag, u64 alloc_time_ns) + struct blk_mq_tags *tags, unsigned int tag, + u64 alloc_time_ns, u64 start_time_ns) { struct blk_mq_ctx *ctx =3D data->ctx; struct blk_mq_hw_ctx *hctx =3D data->hctx; @@ -360,14 +361,11 @@ static struct request *blk_mq_rq_ctx_init(struct blk_= mq_alloc_data *data, } rq->timeout =3D 0; =20 - if (blk_mq_need_time_stamp(rq)) - rq->start_time_ns =3D ktime_get_ns(); - else - rq->start_time_ns =3D 0; rq->part =3D NULL; #ifdef CONFIG_BLK_RQ_ALLOC_TIME rq->alloc_time_ns =3D alloc_time_ns; #endif + rq->start_time_ns =3D start_time_ns; rq->io_start_time_ns =3D 0; rq->stats_sectors =3D 0; rq->nr_phys_segments =3D 0; @@ -405,11 +403,15 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_dat= a *data, struct request *rq; unsigned long tag_mask; int i, nr =3D 0; + u64 start_time_ns =3D 0; =20 tag_mask =3D blk_mq_get_tags(data, data->nr_tags, &tag_offset); if (unlikely(!tag_mask)) return NULL; =20 + if (blk_mq_need_time_stamp(data->rq_flags)) + start_time_ns =3D ktime_get_ns(); + tags =3D blk_mq_tags_from_data(data); for (i =3D 0; tag_mask; i++) { if (!(tag_mask & (1UL << i))) @@ -417,7 +419,7 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data = *data, tag =3D tag_offset + i; prefetch(tags->static_rqs[tag]); tag_mask &=3D ~(1UL << i); - rq =3D blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns); + rq =3D blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns, start_time_ns); rq_list_add(data->cached_rq, rq); nr++; } @@ -431,7 +433,7 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data = *data, static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *d= ata) { struct request_queue *q =3D data->q; - u64 alloc_time_ns =3D 0; + u64 alloc_time_ns =3D 0, start_time_ns =3D 0; struct request *rq; unsigned int tag; =20 @@ -514,8 +516,11 @@ static struct request *__blk_mq_alloc_requests(struct = blk_mq_alloc_data *data) goto retry; } =20 + if (blk_mq_need_time_stamp(data->rq_flags)) + start_time_ns =3D ktime_get_ns(); + return blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag, - alloc_time_ns); + alloc_time_ns, start_time_ns); } =20 static struct request *blk_mq_rq_cache_fill(struct request_queue *q, @@ -1004,7 +1009,7 @@ static inline void __blk_mq_end_request_acct(struct r= equest *rq, u64 now) =20 inline void __blk_mq_end_request(struct request *rq, blk_status_t error) { - if (blk_mq_need_time_stamp(rq)) + if (blk_mq_need_time_stamp(rq->rq_flags)) __blk_mq_end_request_acct(rq, ktime_get_ns()); =20 if (rq->end_io) { diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index f401067ac03a..e8366e9c3388 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -834,9 +834,9 @@ void blk_mq_end_request_batch(struct io_comp_batch *ib); * Only need start/end time stamping if we have iostat or * blk stats enabled, or using an IO scheduler. */ -static inline bool blk_mq_need_time_stamp(struct request *rq) +static inline bool blk_mq_need_time_stamp(req_flags_t rq_flags) { - return (rq->rq_flags & (RQF_IO_STAT | RQF_STATS | RQF_USE_SCHED)); + return (rq_flags & (RQF_IO_STAT | RQF_STATS | RQF_USE_SCHED)); } =20 static inline bool blk_mq_is_reserved_rq(struct request *rq) @@ -860,7 +860,7 @@ static inline bool blk_mq_add_to_batch(struct request *= req, iob->complete =3D complete; else if (iob->complete !=3D complete) return false; - iob->need_ts |=3D blk_mq_need_time_stamp(req); + iob->need_ts |=3D blk_mq_need_time_stamp(req->rq_flags); rq_list_add(&iob->req_list, req); return true; } --=20 2.39.2