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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD85DC4167B for ; Tue, 29 Nov 2022 14:34:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235687AbiK2OeQ (ORCPT ); Tue, 29 Nov 2022 09:34:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42458 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235726AbiK2Od4 (ORCPT ); Tue, 29 Nov 2022 09:33:56 -0500 Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B18AE9B for ; Tue, 29 Nov 2022 06:33:53 -0800 (PST) Received: by mail-pg1-x52f.google.com with SMTP id q71so13161708pgq.8 for ; Tue, 29 Nov 2022 06:33:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; 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=cuxBsu4VDMAPgQORabQ3hLPzi0PvLOfECIVt9tqDIPc=; b=5fbQ/o8HN1uU9Il6X/LoLok2YjQCD3iAUzjAwva8u2Bewi7xDO1eAgXOehjqnG89Vj Pm4lJytLY4HLzDTxDQ57abFDn0FcRz7AX4j3J/t2xwcY5eehmHpqxvSK8qNSkYM2A1qL ZaALy9wnNsf8drMUlQxrEuSZPwM+tpLba4E1LJOjUsxkQJn+d6wlhrHwcE2U4LHYyN5G Ya///j9EpjNnfwrpUqqRMVhx7mygFI/2nWAz9f483CvEih2E5bIJLKij11WLssGjYYm3 76xopDdej5vs9Bvkir9tHFdhagiFnWYdcfTwTy+0UQMEbX7ozDMCRKXhFX+r5emBZADB +K/A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=cuxBsu4VDMAPgQORabQ3hLPzi0PvLOfECIVt9tqDIPc=; b=JZNhroHFe/2ByV0tb3F8O5jg707oeXDNjs59I7DZp4SrKZxNBw20SaXeI+0Z2dqe1m sOWLl8NHZzp1aWuAzOYEwOezaGT5W9DNQGA0MnEdmOYG/FcA5HEoop3D2rgxjSj4z4qZ O97S/i1EGNDp1vHCYzCEHho34Jdwp1uLfy6v2/4ac9B0kT+dsOq0SLS1B4xbwi/Gz1kf w/4E27kG62rpH9wZeIIM4Upmce2Dm/NsRSBTcu63JIkwYp9xyab/G1Xj09WYgk9FB5PK 1ZJ9uRD+zVD3qjL4V8Og33HwnBrkUaPWkBR0OubUWYD24Ip+X3sCs68x2Cbc0kj/4bgo IPnw== X-Gm-Message-State: ANoB5pn2O8JVRilHayRIKWhx+O9ErS01PjHkbbom5vyVK58dlAIaYA5s D/04gdFncyg7xJrIwWW8z8TXKA== X-Google-Smtp-Source: AA0mqf4cAOnifTIeAsmfaAuLmOW0hFwCVqdZbuyJ5wPVOT+Ju8/bLnxagpvq1GBkii7dmlo0kMDu/A== X-Received: by 2002:a65:5543:0:b0:477:dc7f:bf24 with SMTP id t3-20020a655543000000b00477dc7fbf24mr20910314pgr.555.1669732432842; Tue, 29 Nov 2022 06:33:52 -0800 (PST) Received: from [192.168.1.136] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id h11-20020a170902680b00b001745662d568sm2818626plk.278.2022.11.29.06.33.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 29 Nov 2022 06:33:52 -0800 (PST) Message-ID: <9f45de57-353a-08c9-5d7f-57d7acc67b18@kernel.dk> Date: Tue, 29 Nov 2022 07:33:51 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH v2 2/2] nvme: support io stats on the mpath device Content-Language: en-US To: Sagi Grimberg , linux-nvme@lists.infradead.org Cc: Christoph Hellwig , Keith Busch , Chaitanya Kulkarni , Hannes Reinecke , linux-block@vger.kernel.org References: <20221003094344.242593-1-sagi@grimberg.me> <20221003094344.242593-3-sagi@grimberg.me> From: Jens Axboe In-Reply-To: <20221003094344.242593-3-sagi@grimberg.me> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 10/3/22 3:43 AM, Sagi Grimberg wrote: > Our mpath stack device is just a shim that selects a bottom namespace > and submits the bio to it without any fancy splitting. This also means > that we don't clone the bio or have any context to the bio beyond > submission. However it really sucks that we don't see the mpath device > io stats. > > Given that the mpath device can't do that without adding some context > to it, we let the bottom device do it on its behalf (somewhat similar > to the approach taken in nvme_trace_bio_complete). > > When the IO starts, we account the request for multipath IO stats using > REQ_NVME_MPATH_IO_STATS nvme_request flag to avoid queue io stats disable > in the middle of the request. Reviewed-by: Jens Axboe -- Jens Axboe