From patchwork Tue Oct 26 16:51:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naohiro Aota X-Patchwork-Id: 12585213 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 17494C433F5 for ; Tue, 26 Oct 2021 16:51:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2C3E60E8B for ; Tue, 26 Oct 2021 16:51:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236197AbhJZQyB (ORCPT ); Tue, 26 Oct 2021 12:54:01 -0400 Received: from esa5.hgst.iphmx.com ([216.71.153.144]:48179 "EHLO esa5.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233151AbhJZQx7 (ORCPT ); Tue, 26 Oct 2021 12:53:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1635267093; x=1666803093; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=qZ6hwyvPxJb5cGU1xV/Z814Nl/QSyx2D6YLcmVFesAE=; b=fj1gYqN+N0EIT68ELHcfjf+fay1I/4JuqIIXduL/l+DwVe2nD3mterzo HpMTh4SQKN42iiTQX6cbxStdyWyrDrOeK4I8+8TQFbZuHcSwR/ckS0Upn zNFB3YnFMeUPL2DrfqfOr0jZPhQuKHhmcnwP5imfUdfNYQoHyxbUP8GYE TwtSlivyPziclTSFxNbMmIB4FvKwC9d2269VJedSVh6yse/7fX7ntG8pv XWMhVZ1tWmc2kON5WLNyVnSbYi+/HTXKsnWrnqMf1QHa98X7Msraj6654 06rZ9RExV+MdZm1psfJkh0njv39j7jgFyZ85czMbHs7rO9ij995TQFe9C w==; X-IronPort-AV: E=Sophos;i="5.87,184,1631548800"; d="scan'208";a="183889430" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 27 Oct 2021 00:51:33 +0800 IronPort-SDR: dbffmHeYS6qb+GJv9idlyetMxPD6RxrFxrDXXbu3KDdE28925anCW0YSXjAHwofTvdAk0Oe0cW fpFFh5PzdotMVC/CFLqh808elE6Twwq81qv1n8apQLafziMcpOVJj+O349VA55/MXAnjrhDJdo vtEDg451TnfX7ImnCQ7h9qcAMQFP5rDo6Jwna9yOvHG/f9YZdGalSPRUzXVIpDGs8UF8whEA1T tsYRQvzRNGl14gCAuPs9UrDd+/wc11TE7M73m1gIH3+/57lwEXgn0Yp3b6zl+O5AMfZr9Ym1uD xvLDzgvPWqj4J+s21ugqFnBr Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2021 09:25:32 -0700 IronPort-SDR: CBtzhmOEgEB6+xT4dcNmNA4qOE7KrJ/EccPcFSeQxFFi2kH0p+/IttplThYuYUzM8+JM4TRlv1 mHsTh0dwcYyJiOPg+g/6ajrGdg2smbeftXKNVlYx+UIhLZozuMSZnH4DPxXVJ2KIx8gTCEJt65 xcYW8ZIfb33aOhxlmFpWSlBBFyt6oJd8GGa8X1wufrnIcKWDyEWb2aWEl1b3ncviX8yXHOv5U7 /Wywp/kNxn1uR5mAezLDWLjNxOoEKlJHfvGe8DPpTLUxINnlmP3DYVOTErd/asnEvGLG7a6nzm 3jY= WDCIronportException: Internal Received: from 3lpbl13.ad.shared (HELO naota-xeon.wdc.com) ([10.225.49.115]) by uls-op-cesaip01.wdc.com with ESMTP; 26 Oct 2021 09:51:35 -0700 From: Naohiro Aota To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Naohiro Aota , Christoph Hellwig , Niklas Cassel Subject: [PATCH v2] block: schedule queue restart after BLK_STS_ZONE_RESOURCE Date: Wed, 27 Oct 2021 01:51:27 +0900 Message-Id: <20211026165127.4151055-1-naohiro.aota@wdc.com> X-Mailer: git-send-email 2.33.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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 --- Changes from v1 - Rename need_resource to needs_resource to be consistent with needs_restart - Use the if- to set needs_resource when prep == PREP_DISPATCH_NO_BUDGET. 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 9c64f0025a56..dc49483334c7 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1318,6 +1318,7 @@ 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; @@ -1363,6 +1364,8 @@ 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; @@ -1373,6 +1376,7 @@ 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++; @@ -1399,7 +1403,6 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, /* 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; if (nr_budgets) blk_mq_release_budgets(q, list); @@ -1440,14 +1443,16 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, * 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);