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=-7.0 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS autolearn=unavailable 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 531B8C07E85 for ; Wed, 5 Dec 2018 16:25:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 18E002064D for ; Wed, 5 Dec 2018 16:25:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="LaaBKonm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 18E002064D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728229AbeLEQZt (ORCPT ); Wed, 5 Dec 2018 11:25:49 -0500 Received: from mail-it1-f196.google.com ([209.85.166.196]:51799 "EHLO mail-it1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727959AbeLEQZt (ORCPT ); Wed, 5 Dec 2018 11:25:49 -0500 Received: by mail-it1-f196.google.com with SMTP id x19so22238072itl.1 for ; Wed, 05 Dec 2018 08:25:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=vKrjrO3N0vHL4Rqm8qJpRB8z3APMNK7apMQ+HoqTxqk=; b=LaaBKonmJVkBkx75VNJjeKjjK8x41uhlWygWxGuYlkw8D+1vo8Ln/E/5eKIoOFUhUh Gh7jLhSdRVZX3a0WbCyVdlL5MlbmzrHFkQ1qWIMUUiCt1FOPfCt6i45h9FTOx4ETVaCm P+a9KLye+gHvbge2CsNvhxaDhlaRFOVV+Guzi01Y5neoOJVCKv5bZO1UD7DcY+KAkYVM kbhBoxXlEd4OpxvwyIcUJjgBLVTWZIP1/AfpL9epPxmJyTZv7XSfrVG0Kb0j0k3pY3gW hmZw0T5z3BSzWS12sfN2QkkvGmED3ouxnljDeF6VpSSPNTTYKvCOr6WnJz58LMq1LE4C 22dA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=vKrjrO3N0vHL4Rqm8qJpRB8z3APMNK7apMQ+HoqTxqk=; b=kX7GCPk3ZZGXnbZPAz5SKKCcP3rhXcKfUu5AkrIPTAty3DrL9gQMZjQBkDehh7l4UO tv+JNDiq74NGRtEzrIlu5B1taxWPcbzVU6FkPgNAFUoiVVTeMK0kC7zWsbrv3jQNPw6Y 7CSYtybNVOHxb8eXkimiKCHxLZ1MPLDMSYEPNy1sSl2MKBG10aP4ibYepZpqd2s4GnI2 tK7O1VTmlHZzdgiEvgyex1paNTrYy+235J0JgMeYOHETd5O3EH5sYhb3HYeBDaQt5JDB cqRPDtst0EtRkdl0AiYbG4zvatP8LSm6/TWB5US0Fi+Aha6YOtuoBIJZ3DjsZxlu9xDo Q0hg== X-Gm-Message-State: AA+aEWY5JaZCeDQLVcM06yubsnxthZs1fNm5ue33Xu4bQziMFBOjIKs1 NthOd8AMdd2IJRkQACjUahRvqk+VIE0= X-Google-Smtp-Source: AFSGD/XN7205RtAh0F05+bskUug8QE12PABhVueg38NbJtoYVaOcdMvh5YO/9h8N9/7eOlnkn8DizQ== X-Received: by 2002:a02:a791:: with SMTP id e17mr18411185jaj.104.1544027148026; Wed, 05 Dec 2018 08:25:48 -0800 (PST) Received: from [192.168.1.56] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id k18sm8329522ioa.39.2018.12.05.08.25.46 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Dec 2018 08:25:46 -0800 (PST) Subject: Re: [PATCH V9 1/4] blk-mq: insert to hctx dispatch list when bypass_insert is true To: Jianchao Wang Cc: ming.lei@redhat.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <1543995842-20704-1-git-send-email-jianchao.w.wang@oracle.com> <1543995842-20704-2-git-send-email-jianchao.w.wang@oracle.com> From: Jens Axboe Message-ID: <54c7377f-e8e6-92cf-eced-6c76297afd52@kernel.dk> Date: Wed, 5 Dec 2018 09:25:45 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1543995842-20704-2-git-send-email-jianchao.w.wang@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/5/18 12:43 AM, Jianchao Wang wrote: > We don't allow direct dispatch of anything but regular reads/writes > and insert all of non-read-write requests. However, this is not > correct for 'bypass_insert == true' case where inserting is ignored > and BLK_STS_RESOURCE is returned. The caller will fail forever. > > Fix it with inserting the non-read-write request to hctx dispatch > list to avoid to involve merge and io scheduler when bypass_insert > is true. > > Signed-off-by: Jianchao Wang > --- > block/blk-mq.c | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 9005505..153af90 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -1822,6 +1822,7 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, > { > struct request_queue *q = rq->q; > bool run_queue = true; > + bool force = false; > > /* > * RCU or SRCU read lock is needed before checking quiesced flag. > @@ -1836,9 +1837,19 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, > goto insert; > } > > - if (!blk_rq_can_direct_dispatch(rq) || (q->elevator && !bypass_insert)) > + if (q->elevator && !bypass_insert) > goto insert; > > + if (!blk_rq_can_direct_dispatch(rq)) { > + /* > + * For 'bypass_insert == true' case, insert request into hctx > + * dispatch list. > + */ > + if (bypass_insert) > + force = true; > + goto insert; > + } Just do force = bypass_insert, no need for the if. -- Jens Axboe