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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 45025C4338F for ; Thu, 5 Aug 2021 17:42:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2595A61104 for ; Thu, 5 Aug 2021 17:42:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232460AbhHERmZ (ORCPT ); Thu, 5 Aug 2021 13:42:25 -0400 Received: from mail-pj1-f48.google.com ([209.85.216.48]:43612 "EHLO mail-pj1-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231225AbhHERmZ (ORCPT ); Thu, 5 Aug 2021 13:42:25 -0400 Received: by mail-pj1-f48.google.com with SMTP id pj14-20020a17090b4f4eb029017786cf98f9so11348413pjb.2 for ; Thu, 05 Aug 2021 10:42:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=CB7SvHbKMaUaPt3Ci5PlkFunOEsthh1lpDInkmwyLlA=; b=sEg0uIxDULZXjZu9kjQ+yibJ/NkmWN+ax5Zw0E5pzdq8W4snD7QWwk4tEjllsVdTCa OOt9p3q6F3UMLjG0HSy0aMy7CCYaonOLW33LUPPExODqmwWaZSFdmI4wn7OQptU0m/4D +paUvgNkcfIKaH4HSqI2e0KwlHq2QakNtstJFpk/0QaKn4OmdvlX+8lGfjAMydZl9OZz /kpYNWA+6MZWwThu4FPmINPj9t9Uxq8UoOfp7hADGmG5NJlrTIkwsp6o3gfWISLZkDZn I0pDYFfhiw8MGrb9j7bCDQh9KZ1lzx0LLL3vQsCIoxjkzsFZPbVAQu9Lll8mp6wDOweE bDUw== X-Gm-Message-State: AOAM532FoSgn8Kf6n5ABB7Lvx/cb8vIByWKrBmugwe+5rlgRxgQKrI5x hscyEGSH8sRz47XkiNpd+aE= X-Google-Smtp-Source: ABdhPJy99OTKESnYKVhs1h8DOe/uEkPyfcmx7Y3DHSbJQfxPJ7mwv+3LOR9vkl84bkbq+50UgNtyvA== X-Received: by 2002:a17:902:7481:b029:12c:9cf8:bc5f with SMTP id h1-20020a1709027481b029012c9cf8bc5fmr4974202pll.52.1628185329499; Thu, 05 Aug 2021 10:42:09 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:1:93c2:eaf5:530d:627d]) by smtp.gmail.com with ESMTPSA id m11sm10381834pjn.2.2021.08.05.10.42.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Aug 2021 10:42:08 -0700 (PDT) From: Bart Van Assche To: Jens Axboe Cc: linux-block@vger.kernel.org, Christoph Hellwig , Jaegeuk Kim , Bart Van Assche , Ming Lei , Tetsuo Handa , Martijn Coenen Subject: [PATCH v3 1/2] blk-mq: Introduce the BLK_MQ_F_NO_SCHED_BY_DEFAULT flag Date: Thu, 5 Aug 2021 10:41:59 -0700 Message-Id: <20210805174200.3250718-2-bvanassche@acm.org> X-Mailer: git-send-email 2.32.0.605.g8dce9f2422-goog In-Reply-To: <20210805174200.3250718-1-bvanassche@acm.org> References: <20210805174200.3250718-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org elevator_get_default() uses the following algorithm to select an I/O scheduler from inside add_disk(): - In case of a single hardware queue or if sharing hardware queues across multiple request queues (BLK_MQ_F_TAG_HCTX_SHARED), use mq-deadline. - Otherwise, use 'none'. This is a good choice for most but not for all block drivers. Make it possible to override the selection of mq-deadline with a new flag, namely BLK_MQ_F_NO_SCHED_BY_DEFAULT. Cc: Christoph Hellwig Cc: Ming Lei Cc: Tetsuo Handa Cc: Martijn Coenen Cc: Jaegeuk Kim Signed-off-by: Bart Van Assche --- block/elevator.c | 3 +++ include/linux/blk-mq.h | 6 ++++++ 2 files changed, 9 insertions(+) diff --git a/block/elevator.c b/block/elevator.c index 52ada14cfe45..d0295e68f481 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -630,6 +630,9 @@ static inline bool elv_support_iosched(struct request_queue *q) */ static struct elevator_type *elevator_get_default(struct request_queue *q) { + if (q->tag_set && q->tag_set->flags & BLK_MQ_F_NO_SCHED_BY_DEFAULT) + return NULL; + if (q->nr_hw_queues != 1 && !blk_mq_is_sbitmap_shared(q->tag_set->flags)) return NULL; diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 1d18447ebebc..22215db36122 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -404,7 +404,13 @@ enum { BLK_MQ_F_STACKING = 1 << 2, BLK_MQ_F_TAG_HCTX_SHARED = 1 << 3, BLK_MQ_F_BLOCKING = 1 << 5, + /* Do not allow an I/O scheduler to be configured. */ BLK_MQ_F_NO_SCHED = 1 << 6, + /* + * Select 'none' during queue registration in case of a single hwq + * or shared hwqs instead of 'mq-deadline'. + */ + BLK_MQ_F_NO_SCHED_BY_DEFAULT = 1 << 7, BLK_MQ_F_ALLOC_POLICY_START_BIT = 8, BLK_MQ_F_ALLOC_POLICY_BITS = 1,