From patchwork Sat Sep 2 15:17:16 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 9935587 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B7BF7601A1 for ; Sat, 2 Sep 2017 15:18:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AB3802863E for ; Sat, 2 Sep 2017 15:18:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A06402863F; Sat, 2 Sep 2017 15:18:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E2C6128641 for ; Sat, 2 Sep 2017 15:18:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752677AbdIBPR4 (ORCPT ); Sat, 2 Sep 2017 11:17:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44880 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752660AbdIBPR4 (ORCPT ); Sat, 2 Sep 2017 11:17:56 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D7A4A81E0E; Sat, 2 Sep 2017 15:17:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com D7A4A81E0E Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx01.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=ming.lei@redhat.com Received: from localhost (ovpn-12-34.pek2.redhat.com [10.72.12.34]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1D8987D975; Sat, 2 Sep 2017 15:17:46 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig Cc: Bart Van Assche , Laurence Oberman , Paolo Valente , Mel Gorman , Ming Lei Subject: [PATCH V4 01/14] blk-mq-sched: fix scheduler bad performance Date: Sat, 2 Sep 2017 23:17:16 +0800 Message-Id: <20170902151729.6162-2-ming.lei@redhat.com> In-Reply-To: <20170902151729.6162-1-ming.lei@redhat.com> References: <20170902151729.6162-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Sat, 02 Sep 2017 15:17:56 +0000 (UTC) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When hw queue is busy, we shouldn't take requests from scheduler queue any more, otherwise it is difficult to do IO merge. This patch fixes the awful IO performance on some SCSI devices(lpfc, qla2xxx, ...) when mq-deadline/kyber is used by not taking requests if hw queue is busy. Reviewed-by: Bart Van Assche Signed-off-by: Ming Lei Reviewed-by: Omar Sandoval --- block/blk-mq-sched.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 4ab69435708c..845e5baf8af1 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -94,7 +94,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) struct request_queue *q = hctx->queue; struct elevator_queue *e = q->elevator; const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; - bool did_work = false; + bool do_sched_dispatch = true; LIST_HEAD(rq_list); /* RCU or SRCU read lock is needed before checking quiesced flag */ @@ -125,7 +125,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) */ if (!list_empty(&rq_list)) { blk_mq_sched_mark_restart_hctx(hctx); - did_work = blk_mq_dispatch_rq_list(q, &rq_list); + do_sched_dispatch = blk_mq_dispatch_rq_list(q, &rq_list); } else if (!has_sched_dispatch) { blk_mq_flush_busy_ctxs(hctx, &rq_list); blk_mq_dispatch_rq_list(q, &rq_list); @@ -136,7 +136,7 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) * on the dispatch list, OR if we did have work but weren't able * to make progress. */ - if (!did_work && has_sched_dispatch) { + if (do_sched_dispatch && has_sched_dispatch) { do { struct request *rq;