From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7162F204F9D; Tue, 3 Dec 2024 15:37:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733240235; cv=none; b=LFqdKC4oKVHiuD/e4gZYTsl4yKa5yZF3PQYjR6juHYa38Rm9EopOEE6RzjSB4V/A3Ppm9geZOrVXb5dKOGZamxpMWz4G9e7qYmWhtTeI6bZpPTgD5KTNA39OTO5BG8RudMisbHAPUQKoE1JIiMb5+iAsAmFWpRzrAnMce4wgvFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733240235; c=relaxed/simple; bh=4TrFMZHjIJLA1wJxaJEeffAk13tPsi30NR4DU6Ph8Uc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZJP7Xl+kZjy2XeKOw54xTmSwjG6NBg/yXjI2Ox6DkSgfi0EHXPm2r8tuN6dhjgnOPW7Ht9mC4P9TS4JnrstBI3oOJeq0sSCK3lKxpkjUOlZOxF/DyX8ExcXvLI9M77js23rofhLmfu19qB26N9ygi0a23s84LTrSRXNbuXAEfTc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=T38+vl8Q; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="T38+vl8Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A14EBC4CED8; Tue, 3 Dec 2024 15:37:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733240235; bh=4TrFMZHjIJLA1wJxaJEeffAk13tPsi30NR4DU6Ph8Uc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T38+vl8Q3jgqTc97z51OftfAuMgKrKIpc/TzyasTyaeugNCjxgCEeyPP/mI9yuuMQ JIxw8jd/HEei5O/hwIQwy+FKn0ZdFfD7DFheNAV8p9icKPh5QxCQuzCNwcODf81+iZ +xhgtgeu3S+1E3ojukbW9J5X1gAK185Cvtru+VTA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christoph Hellwig , Jens Axboe , Sasha Levin Subject: [PATCH 6.12 038/826] nvme-pci: reverse request order in nvme_queue_rqs Date: Tue, 3 Dec 2024 15:36:05 +0100 Message-ID: <20241203144744.948307361@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241203144743.428732212@linuxfoundation.org> References: <20241203144743.428732212@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christoph Hellwig [ Upstream commit beadf0088501d9dcf2454b05d90d5d31ea3ba55f ] blk_mq_flush_plug_list submits requests in the reverse order that they were submitted, which leads to a rather suboptimal I/O pattern especially in rotational devices. Fix this by rewriting nvme_queue_rqs so that it always pops the requests from the passed in request list, and then adds them to the head of a local submit list. This actually simplifies the code a bit as it removes the complicated list splicing, at the cost of extra updates of the rq_next pointer. As that should be cache hot anyway it should be an easy price to pay. Fixes: d62cbcf62f2f ("nvme: add support for mq_ops->queue_rqs()") Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241113152050.157179-2-hch@lst.de Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- drivers/nvme/host/pci.c | 39 +++++++++++++++++---------------------- 1 file changed, 17 insertions(+), 22 deletions(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 34daf6d8db07b..55af3dfbc2607 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -905,9 +905,10 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx, static void nvme_submit_cmds(struct nvme_queue *nvmeq, struct request **rqlist) { + struct request *req; + spin_lock(&nvmeq->sq_lock); - while (!rq_list_empty(*rqlist)) { - struct request *req = rq_list_pop(rqlist); + while ((req = rq_list_pop(rqlist))) { struct nvme_iod *iod = blk_mq_rq_to_pdu(req); nvme_sq_copy_cmd(nvmeq, &iod->cmd); @@ -932,31 +933,25 @@ static bool nvme_prep_rq_batch(struct nvme_queue *nvmeq, struct request *req) static void nvme_queue_rqs(struct request **rqlist) { - struct request *req, *next, *prev = NULL; + struct request *submit_list = NULL; struct request *requeue_list = NULL; + struct request **requeue_lastp = &requeue_list; + struct nvme_queue *nvmeq = NULL; + struct request *req; - rq_list_for_each_safe(rqlist, req, next) { - struct nvme_queue *nvmeq = req->mq_hctx->driver_data; - - if (!nvme_prep_rq_batch(nvmeq, req)) { - /* detach 'req' and add to remainder list */ - rq_list_move(rqlist, &requeue_list, req, prev); - - req = prev; - if (!req) - continue; - } + while ((req = rq_list_pop(rqlist))) { + if (nvmeq && nvmeq != req->mq_hctx->driver_data) + nvme_submit_cmds(nvmeq, &submit_list); + nvmeq = req->mq_hctx->driver_data; - if (!next || req->mq_hctx != next->mq_hctx) { - /* detach rest of list, and submit */ - req->rq_next = NULL; - nvme_submit_cmds(nvmeq, rqlist); - *rqlist = next; - prev = NULL; - } else - prev = req; + if (nvme_prep_rq_batch(nvmeq, req)) + rq_list_add(&submit_list, req); /* reverse order */ + else + rq_list_add_tail(&requeue_lastp, req); } + if (nvmeq) + nvme_submit_cmds(nvmeq, &submit_list); *rqlist = requeue_list; } -- 2.43.0