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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 94753C433B4 for ; Tue, 4 May 2021 00:32:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DA9961244 for ; Tue, 4 May 2021 00:32:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229602AbhEDAdC (ORCPT ); Mon, 3 May 2021 20:33:02 -0400 Received: from mail-pg1-f175.google.com ([209.85.215.175]:36663 "EHLO mail-pg1-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229497AbhEDAdB (ORCPT ); Mon, 3 May 2021 20:33:01 -0400 Received: by mail-pg1-f175.google.com with SMTP id c21so904654pgg.3 for ; Mon, 03 May 2021 17:32:08 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=IHv+UvXamHSoFZjnPZ2YUdrp9AWySR30qYrdTwwJyYU=; b=CKjWL488fYtsCbY56eAx5PbJdfo8183UYq8+NONLx0fPECB8ksmm1iJffyas3sznmx lM0ASr55gudTiW0FfDcvg+DORsamokG1mKzU0wIknXiFcXyGC6AAlo3itrGb6KXXtX1C e9fFU3Wbu8AT2bQwfFJXQwFNsKG/L2LOOzazgVk2xN6k2aNgb/eqWDgSqE1c4LKkvIxA qqY4n050cPOqKslz33MSR2oIEb9lwC2se5HxiPeRparGzFU/nu2d3DKasLvkcwhDCAV9 oYEfpt8v6NyMwPVoWpj2bJUsa6yuM9Wg5tQfUKCwNEcI53Ze2nhkHPB4C6XbjnS1hNXE 664g== X-Gm-Message-State: AOAM530+i3wi353yWHMBWo62IWSYSAINSo2GpyUwvjDbJi5fiwWID3Se 4j2UuqUhwqATddr4GvGfkdu7BeXaZfw= X-Google-Smtp-Source: ABdhPJw1mpvQ4tcVtz6VkCDdk3zKw5qd8NkSI12m9t1PLMBGtiocXRoVUGBoXBzI4G91ghzUTw8t3Q== X-Received: by 2002:a05:6a00:1513:b029:28e:d34b:9cdf with SMTP id q19-20020a056a001513b029028ed34b9cdfmr1681080pfu.67.1620088327274; Mon, 03 May 2021 17:32:07 -0700 (PDT) Received: from ?IPv6:2601:647:4000:d7:6b81:314d:2541:7829? ([2601:647:4000:d7:6b81:314d:2541:7829]) by smtp.gmail.com with ESMTPSA id o4sm10456235pjg.2.2021.05.03.17.32.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 May 2021 17:32:06 -0700 (PDT) Subject: Re: [PATCH] null_blk: poll queue support To: Jens Axboe , "linux-block@vger.kernel.org" References: <725ea863-c754-addf-f143-71d7e2f273de@acm.org> <5e0c7e2f-3fe4-7537-98f5-b9c6de8e5c8f@kernel.dk> From: Bart Van Assche Message-ID: <1bcdc63d-dc1e-c863-07e1-1d957b936a1a@acm.org> Date: Mon, 3 May 2021 17:32:05 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <5e0c7e2f-3fe4-7537-98f5-b9c6de8e5c8f@kernel.dk> 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 5/3/21 10:42 AM, Jens Axboe wrote: > On 5/3/21 9:47 AM, Bart Van Assche wrote: >> On 4/17/21 8:29 AM, Jens Axboe wrote: >>> There's currently no way to experiment with polled IO with null_blk, >>> which seems like an oversight. This patch adds support for polled IO. >>> We keep a list of issued IOs on submit, and then process that list >>> when mq_ops->poll() is invoked. >>> >>> A new parameter is added, poll_queues. It defaults to 1 like the >>> submit queues, meaning we'll have 1 poll queue available. >> >> Has anyone run blktests against blk-for-next since this patch got >> queued? The following appears in the kernel log if I run blktests: > > Do you know what parameters the module was loaded with? I'll drop this > one from the 5.13 queue for now. Hi Jens, The call trace was reported about 35 seconds after the message indicating the start of the test so I assume that the null_blk driver was loaded by the following shell code from tests/block/010: if ! _init_null_blk queue_mode=2 submit_queues=16 nr_devices=32 shared_tags=1; then return 1 fi Bart.