From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 15543128392 for ; Tue, 5 Mar 2024 16:08:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709654930; cv=none; b=OCbARsVmlpiEwPOVAoNRukOrUE7YE2y6ce0JXKbFdkVLmQi3wMJftgUFzZzhfdb6bhFdZt4YtxPBkbDOLoXbg+3dTd0YQevE4m7r+uPeWpbjrQlkt8kl2x+U78wiA+rF7Lszf54C+BypF7ojiRDHW1oPXzk1GzE7AwGweN2uvds= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709654930; c=relaxed/simple; bh=mIBe9C22FxWEWX02cGhRxqJ/jUNOmxYaoZIj+zD5bao=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=i01C24A3+FgGu3Reox25kfJB+xiwouSfvrPmHmiLCihhKeYXcv42OQM2VqMaSOKFhmO6GWwLuclyV9syn+eFr2XBrQ0A3HqDXtxTfHIDMoDtctmxBPyC7nQFR7z9CDM1qZn3et0My7jfI52KkfHm4uVYz3CF0Odb65JB9QukpQA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=PgvUR/zF; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="PgvUR/zF" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-1db9cb6dcb5so17964625ad.1 for ; Tue, 05 Mar 2024 08:08:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1709654927; x=1710259727; darn=lists.linux.dev; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=ySXwHaWnwWfuqJedGiV+eti2ui1J2NF0RPAqqwKPf6w=; b=PgvUR/zFQqPNC3487j9ZNFe3tIjZJiE+mO1gYQJ/MHQzokPmJha7pBmn4M1Mc3hw3g PucH1ENgEfzZq86pNTuqnrOZ8KmY5GX/BX/5ehh4aOyLcBOyC2kkkw+PhZR58DZhhzNg jP8HtYGch4rnXFsYcG36FEqoGWuzCAEAqZL7xM7vj77rgKd5t4VgnKouXFMekGVwqimq 8/8GwrrGVKlCQY1rynJx+QifWVxMqNVmmPcDsheJzK0suAnNKNc5tRtG9AGuYn9xo9V1 WpFBXQW3SdVS6M9v0OVXDBE/w2I+RzvIjipPBbNy78BShHuARIQD6nDqxqV4l+7QHmWS QXgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709654927; x=1710259727; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ySXwHaWnwWfuqJedGiV+eti2ui1J2NF0RPAqqwKPf6w=; b=s8rBoemul3xfFIhGEZwUe6ghcgj4mF3H/NOssOCktx/YM1FTIx2RS0MG7rv57vjXwr dGeWqBkIlLFkACcbckGRO5ssu3JDdSdTpeChoDk2qsOXHtI1i1yUDBpCvbXcus/kEXnV gsW9lLdM/gMR3iDW92uBnzBlWi/OudxQkDg2IA2JFqGJ8pOUGCv5TVFtgEl+taqi//te flzPcu+6D4LCj3Yhs2YVPeRaSBA7BkBiy7QtZk2GM8qlbIWouxwtP9TaTOMw5Wxp0v7z YIwAzojZj46rNVodBvn63tfVdagKcS3mwqn2TgkrFHIegbQqEh4ATy/OGu7vvtQ2WO4C Ix3A== X-Forwarded-Encrypted: i=1; AJvYcCU3ohYplc3tIBlbyhgtEpbvrvHdgNxK/0TEBeQsgVqz5opRfLxNTk0E6YivVHIwtRdvZAWOsi/MTqJTp6G2R5fveZU3EXg= X-Gm-Message-State: AOJu0YxUvqfCO6Y0WaHreMKVeiVOpt9Nmd1+9AP24Y9gUYzRg/S86aGB PIWXL6SiPBLktxd2EPh8Acksd+UU7CU0sMrkmM8Qf/wRclYERtfax/7MJwoy4ZM= X-Google-Smtp-Source: AGHT+IEQyMNsi91T5s32CUzK+ybKvXY5CY8IcxZgQ/czWV6ISp8aawkZe242UlnjfOr6MXQ5ygWb4g== X-Received: by 2002:a17:902:b08b:b0:1dc:82bc:c072 with SMTP id p11-20020a170902b08b00b001dc82bcc072mr977677plr.1.1709654927270; Tue, 05 Mar 2024 08:08:47 -0800 (PST) Received: from [192.168.1.150] ([198.8.77.194]) by smtp.gmail.com with ESMTPSA id b4-20020a170902d50400b001dcf93e90a0sm6901815plg.20.2024.03.05.08.08.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Mar 2024 08:08:46 -0800 (PST) Message-ID: <06787e6a-4e78-4524-960d-ec24b9f38191@kernel.dk> Date: Tue, 5 Mar 2024 09:08:43 -0700 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC RESEND 16/16] nvme-pci: use blk_rq_dma_map() for NVMe SGL Content-Language: en-US To: Keith Busch , Leon Romanovsky Cc: Christoph Hellwig , Robin Murphy , Marek Szyprowski , Joerg Roedel , Will Deacon , Jason Gunthorpe , Chaitanya Kulkarni , Chaitanya Kulkarni , Jonathan Corbet , Sagi Grimberg , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, kvm@vger.kernel.org, linux-mm@kvack.org, Bart Van Assche , Damien Le Moal , Amir Goldstein , "josef@toxicpanda.com" , "Martin K. Petersen" , "daniel@iogearbox.net" , Dan Williams , "jack@suse.com" , Leon Romanovsky , Zhu Yanjun References: <016fc02cbfa9be3c156a6f74df38def1e09c08f1.1709635535.git.leon@kernel.org> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/5/24 8:51 AM, Keith Busch wrote: > On Tue, Mar 05, 2024 at 01:18:47PM +0200, Leon Romanovsky wrote: >> @@ -236,7 +236,9 @@ struct nvme_iod { >> unsigned int dma_len; /* length of single DMA segment mapping */ >> dma_addr_t first_dma; >> dma_addr_t meta_dma; >> - struct sg_table sgt; >> + struct dma_iova_attrs iova; >> + dma_addr_t dma_link_address[128]; >> + u16 nr_dma_link_address; >> union nvme_descriptor list[NVME_MAX_NR_ALLOCATIONS]; >> }; > > That's quite a lot of space to add to the iod. We preallocate one for > every request, and there could be millions of them. Yeah, that's just a complete non-starter. As far as I can tell, this ends up adding 1052 bytes per request. Doing the quick math on my test box (24 drives), that's just a smidge over 3GB of extra memory. That's not going to work, not even close. -- Jens Axboe