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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6553AC433EF for ; Mon, 15 Nov 2021 19:07:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FEA6636EA for ; Mon, 15 Nov 2021 19:07:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244021AbhKOTJ6 (ORCPT ); Mon, 15 Nov 2021 14:09:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:54896 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238574AbhKORmL (ORCPT ); Mon, 15 Nov 2021 12:42:11 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0DB1363244; Mon, 15 Nov 2021 17:27:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1636997257; bh=+HyW3jFR8/EdW6DEw9/OuVym9+rQMFtOIpWINHF0u3Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=x4HYioAEB0tXowKYsXuVJD3/KgotNswRnF4j5uiDnRQKMua+k/rE0cIWPkn18raXw GX1cMX/zqkQdTVWE1VVnx9hSuwDUhcubw+FO6tow86HLkJPsKb6hVqsGfuxN1nTjhK 92JWPwk9pjKZVXxzAx6D5nogR//Vno7uNHDr/n1g= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Naohiro Aota , Christoph Hellwig , Niklas Cassel , Jens Axboe , Sasha Levin Subject: [PATCH 5.10 075/575] block: schedule queue restart after BLK_STS_ZONE_RESOURCE Date: Mon, 15 Nov 2021 17:56:40 +0100 Message-Id: <20211115165346.229918629@linuxfoundation.org> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211115165343.579890274@linuxfoundation.org> References: <20211115165343.579890274@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Naohiro Aota [ Upstream commit 9586e67b911c95ba158fcc247b230e9c2d718623 ] When dispatching a zone append write request to a SCSI zoned block device, if the target zone of the request is already locked, the device driver will return BLK_STS_ZONE_RESOURCE and the request will be pushed back to the hctx dipatch queue. The queue will be marked as RESTART in dd_finish_request() and restarted in __blk_mq_free_request(). However, this restart applies to the hctx of the completed request. If the requeued request is on a different hctx, dispatch will no be retried until another request is submitted or the next periodic queue run triggers, leading to up to 30 seconds latency for the requeued request. Fix this problem by scheduling a queue restart similarly to the BLK_STS_RESOURCE case or when we cannot get the budget. Also, consolidate the checks into the "need_resource" variable to simplify the condition. Signed-off-by: Naohiro Aota Reviewed-by: Christoph Hellwig Cc: Niklas Cassel Link: https://lore.kernel.org/r/20211026165127.4151055-1-naohiro.aota@wdc.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-mq.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index eed9a4c1519df..69cc552c3dfc9 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1327,6 +1327,7 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, int errors, queued; blk_status_t ret = BLK_STS_OK; LIST_HEAD(zone_list); + bool needs_resource = false; if (list_empty(list)) return false; @@ -1372,6 +1373,8 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, queued++; break; case BLK_STS_RESOURCE: + needs_resource = true; + fallthrough; case BLK_STS_DEV_RESOURCE: blk_mq_handle_dev_resource(rq, list); goto out; @@ -1382,6 +1385,7 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, * accept. */ blk_mq_handle_zone_resource(rq, &zone_list); + needs_resource = true; break; default: errors++; @@ -1408,7 +1412,6 @@ out: /* For non-shared tags, the RESTART check will suffice */ bool no_tag = prep == PREP_DISPATCH_NO_TAG && (hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED); - bool no_budget_avail = prep == PREP_DISPATCH_NO_BUDGET; blk_mq_release_budgets(q, nr_budgets); @@ -1448,14 +1451,16 @@ out: * If driver returns BLK_STS_RESOURCE and SCHED_RESTART * bit is set, run queue after a delay to avoid IO stalls * that could otherwise occur if the queue is idle. We'll do - * similar if we couldn't get budget and SCHED_RESTART is set. + * similar if we couldn't get budget or couldn't lock a zone + * and SCHED_RESTART is set. */ needs_restart = blk_mq_sched_needs_restart(hctx); + if (prep == PREP_DISPATCH_NO_BUDGET) + needs_resource = true; if (!needs_restart || (no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) blk_mq_run_hw_queue(hctx, true); - else if (needs_restart && (ret == BLK_STS_RESOURCE || - no_budget_avail)) + else if (needs_restart && needs_resource) blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY); blk_mq_update_dispatch_busy(hctx, true); -- 2.33.0