From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB1ADC433EF for ; Wed, 13 Oct 2021 15:49:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97CC2610A2 for ; Wed, 13 Oct 2021 15:49:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229664AbhJMPva (ORCPT ); Wed, 13 Oct 2021 11:51:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40632 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229653AbhJMPv3 (ORCPT ); Wed, 13 Oct 2021 11:51:29 -0400 Received: from mail-il1-x135.google.com (mail-il1-x135.google.com [IPv6:2607:f8b0:4864:20::135]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4CE6C061570 for ; Wed, 13 Oct 2021 08:49:25 -0700 (PDT) Received: by mail-il1-x135.google.com with SMTP id i11so154977ila.12 for ; Wed, 13 Oct 2021 08:49:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=s2SV06/OAwoXYtJwNkm3enj3iJ/XQZ4SN5/CerSv24w=; b=ZLQDrFdjZaXsSZXJ003hpRNbWeyYgqgIHkfL6C40k2N/OIZMvmmgs1QOCLAys/nSKs mzNSfwEBK3I6looRU+i/V+7UmdV9q2TddJVyQDec3C2x/exEPGLJIS4rUmoNcCrArWkn 4IOIQTp60uPB0GAATH3ZDZLrXq8wpBvsrN4Q0RKXPt6wvbX3PxAaTqceVZutxmla8it6 ua4Qc6ZL7SWcP5q6wOsfLSiaKl+8djWLhzRLvhfuK897uN3ilNWLvwwjXs8eVnBEfQAo 4OIShUXBN7wSCeIaH/HP0nxUxS+Sttf5CjfcPc2J3TrGq/bTmXwEvOZwd4Hk1wh8LPds kx0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=s2SV06/OAwoXYtJwNkm3enj3iJ/XQZ4SN5/CerSv24w=; b=i0HwKtu1/rhocUj+TF3GOewV5BJR/ZKN/cP7HQBqUMqDvN+sG+hRQi1jgCwsuLEHZu OAreCDPahQFoKjVkDWw64Do+Yz/jvamULb/JZZKuOEZoAorVDvMmU6UGR9iSE3deX/kN uznvcoCOLpLO0EwCEKjtHksPkEZHedCIJ+3WYimHAIubvP2zIYJJtqldsHAotASQCXDx RSgecWprYgw4mobrAb6VRrFXjHblbNXarkX594/dvtGL3OkbgU5qMPJXuf1+MMtyxIZd QScRqgjj8LkjNinMzWWFoH3yVaPWjsAtgkSGN57oC8bXpWQaKFcLL2Wk4ZrALazSAhXg BcaQ== X-Gm-Message-State: AOAM532OYURFJzyvEUtvQZkl4GZLLZs8pZqdLBF4G+XsSfOpxKB2ldqX sO5giazg8BCDEvFWJ0t5i/KLb2bUeYhzcg== X-Google-Smtp-Source: ABdhPJweO1CQ9AZQ5ugWQ/kd4gKNcSfYYO8MtrGrAGiDFofo4V2RV6BU72iS8GVdLSdjdDJsiB+TLQ== X-Received: by 2002:a05:6e02:1a61:: with SMTP id w1mr199182ilv.197.1634140164960; Wed, 13 Oct 2021 08:49:24 -0700 (PDT) Received: from [192.168.1.30] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id z11sm7176377ilb.11.2021.10.13.08.49.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 13 Oct 2021 08:49:24 -0700 (PDT) Subject: Re: [PATCH 6/9] nvme: add support for batched completion of polled IO From: Jens Axboe To: Christoph Hellwig Cc: linux-block@vger.kernel.org References: <20211012181742.672391-1-axboe@kernel.dk> <20211012181742.672391-7-axboe@kernel.dk> <03bccee7-de50-0118-994d-4c1a23ce384a@kernel.dk> Message-ID: Date: Wed, 13 Oct 2021 09:49:24 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 10/13/21 9:42 AM, Jens Axboe wrote: > On 10/13/21 9:16 AM, Christoph Hellwig wrote: >> On Wed, Oct 13, 2021 at 09:10:01AM -0600, Jens Axboe wrote: >>>> Also - can you look into turning this logic into an inline function with >>>> a callback for the driver? I think in general gcc will avoid the >>>> indirect call for function pointers passed directly. That way we can >>>> keep a nice code structure but also avoid the indirections. >>>> >>>> Same for nvme_pci_complete_batch. >>> >>> Not sure I follow. It's hard to do a generic callback for this, as the >>> batch can live outside the block layer through the plug. That's why >>> it's passed the way it is in terms of completion hooks. >> >> Basically turn nvme_pci_complete_batch into a core nvme helper (inline) >> with nvme_pci_unmap_rq passed as a function pointer that gets inlined. > > Something like this? Full patch below for reference, might be easier to read. Got rid of the prep patch for nvme as well, so this is everything. commit 002fcc4dd9869cd0fc8684b37ede8e20bdca16a4 Author: Jens Axboe Date: Fri Oct 8 05:59:37 2021 -0600 nvme: add support for batched completion of polled IO Take advantage of struct io_batch, if passed in to the nvme poll handler. If it's set, rather than complete each request individually inline, store them in the io_batch list. We only do so for requests that will complete successfully, anything else will be completed inline as before. Add an mq_ops->complete_batch() handler to do the post-processing of the io_batch list once polling is complete. Signed-off-by: Jens Axboe diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index c2c2e8545292..26328fd26ff0 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -346,15 +346,19 @@ static inline enum nvme_disposition nvme_decide_disposition(struct request *req) return RETRY; } -static inline void nvme_end_req(struct request *req) +static inline void nvme_end_req_zoned(struct request *req) { - blk_status_t status = nvme_error_status(nvme_req(req)->status); - if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) && req_op(req) == REQ_OP_ZONE_APPEND) req->__sector = nvme_lba_to_sect(req->q->queuedata, le64_to_cpu(nvme_req(req)->result.u64)); +} + +static inline void nvme_end_req(struct request *req) +{ + blk_status_t status = nvme_error_status(nvme_req(req)->status); + nvme_end_req_zoned(req); nvme_trace_bio_complete(req); blk_mq_end_request(req, status); } @@ -381,6 +385,23 @@ void nvme_complete_rq(struct request *req) } EXPORT_SYMBOL_GPL(nvme_complete_rq); +void nvme_complete_batch(struct io_batch *iob, void (*fn)(struct request *rq)) +{ + struct request *req; + + req = rq_list_peek(&iob->req_list); + while (req) { + fn(req); + nvme_cleanup_cmd(req); + nvme_end_req_zoned(req); + req->status = BLK_STS_OK; + req = rq_list_next(req); + } + + blk_mq_end_request_batch(iob); +} +EXPORT_SYMBOL_GPL(nvme_complete_batch); + /* * Called to unwind from ->queue_rq on a failed command submission so that the * multipathing code gets called to potentially failover to another path. diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index ed79a6c7e804..b73a573472d9 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -638,6 +638,7 @@ static inline bool nvme_is_aen_req(u16 qid, __u16 command_id) } void nvme_complete_rq(struct request *req); +void nvme_complete_batch(struct io_batch *iob, void (*fn)(struct request *)); blk_status_t nvme_host_path_error(struct request *req); bool nvme_cancel_request(struct request *req, void *data, bool reserved); void nvme_cancel_tagset(struct nvme_ctrl *ctrl); diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 9db6e23f41ef..b3e686404adf 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -959,7 +959,7 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx, return ret; } -static void nvme_pci_complete_rq(struct request *req) +static void nvme_pci_unmap_rq(struct request *req) { struct nvme_iod *iod = blk_mq_rq_to_pdu(req); struct nvme_dev *dev = iod->nvmeq->dev; @@ -969,9 +969,19 @@ static void nvme_pci_complete_rq(struct request *req) rq_integrity_vec(req)->bv_len, rq_data_dir(req)); if (blk_rq_nr_phys_segments(req)) nvme_unmap_data(dev, req); +} + +static void nvme_pci_complete_rq(struct request *req) +{ + nvme_pci_unmap_rq(req); nvme_complete_rq(req); } +static void nvme_pci_complete_batch(struct io_batch *iob) +{ + nvme_complete_batch(iob, nvme_pci_unmap_rq); +} + /* We read the CQE phase first to check if the rest of the entry is valid */ static inline bool nvme_cqe_pending(struct nvme_queue *nvmeq) { @@ -996,7 +1006,8 @@ static inline struct blk_mq_tags *nvme_queue_tagset(struct nvme_queue *nvmeq) return nvmeq->dev->tagset.tags[nvmeq->qid - 1]; } -static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx) +static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, + struct io_batch *iob, u16 idx) { struct nvme_completion *cqe = &nvmeq->cqes[idx]; __u16 command_id = READ_ONCE(cqe->command_id); @@ -1023,8 +1034,17 @@ static inline void nvme_handle_cqe(struct nvme_queue *nvmeq, u16 idx) } trace_nvme_sq(req, cqe->sq_head, nvmeq->sq_tail); - if (!nvme_try_complete_req(req, cqe->status, cqe->result)) - nvme_pci_complete_rq(req); + if (!nvme_try_complete_req(req, cqe->status, cqe->result)) { + /* + * Do normal inline completion if we don't have a batch + * list, if we have an end_io handler, or if the status of + * the request isn't just normal success. + */ + if (!iob || req->end_io || nvme_req(req)->status) + nvme_pci_complete_rq(req); + else + rq_list_add_tail(&iob->req_list, req); + } } static inline void nvme_update_cq_head(struct nvme_queue *nvmeq) @@ -1050,7 +1070,7 @@ static inline int nvme_process_cq(struct nvme_queue *nvmeq) * the cqe requires a full read memory barrier */ dma_rmb(); - nvme_handle_cqe(nvmeq, nvmeq->cq_head); + nvme_handle_cqe(nvmeq, NULL, nvmeq->cq_head); nvme_update_cq_head(nvmeq); } @@ -1092,6 +1112,27 @@ static void nvme_poll_irqdisable(struct nvme_queue *nvmeq) enable_irq(pci_irq_vector(pdev, nvmeq->cq_vector)); } +static inline int nvme_poll_cq(struct nvme_queue *nvmeq, struct io_batch *iob) +{ + int found = 0; + + while (nvme_cqe_pending(nvmeq)) { + found++; + /* + * load-load control dependency between phase and the rest of + * the cqe requires a full read memory barrier + */ + dma_rmb(); + nvme_handle_cqe(nvmeq, iob, nvmeq->cq_head); + nvme_update_cq_head(nvmeq); + } + + if (found) + nvme_ring_cq_doorbell(nvmeq); + return found; +} + + static int nvme_poll(struct blk_mq_hw_ctx *hctx, struct io_batch *iob) { struct nvme_queue *nvmeq = hctx->driver_data; @@ -1101,7 +1142,7 @@ static int nvme_poll(struct blk_mq_hw_ctx *hctx, struct io_batch *iob) return 0; spin_lock(&nvmeq->cq_poll_lock); - found = nvme_process_cq(nvmeq); + found = nvme_poll_cq(nvmeq, iob); spin_unlock(&nvmeq->cq_poll_lock); return found; @@ -1639,6 +1680,7 @@ static const struct blk_mq_ops nvme_mq_admin_ops = { static const struct blk_mq_ops nvme_mq_ops = { .queue_rq = nvme_queue_rq, .complete = nvme_pci_complete_rq, + .complete_batch = nvme_pci_complete_batch, .commit_rqs = nvme_commit_rqs, .init_hctx = nvme_init_hctx, .init_request = nvme_init_request, -- Jens Axboe