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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C802EC4167B for ; Mon, 4 Oct 2021 13:27:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACDEB611CA for ; Mon, 4 Oct 2021 13:27:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236593AbhJDN26 (ORCPT ); Mon, 4 Oct 2021 09:28:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:43492 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236722AbhJDN1L (ORCPT ); Mon, 4 Oct 2021 09:27:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 523FA61B72; Mon, 4 Oct 2021 13:11:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633353118; bh=90CvL/O49qy5C+G7Aq+mqE2wEL7AFDCuIoCUyt0bVfA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RitOpha2BlF+fZIwoUQhzAXnlCD+xDXCOUNvNoLYovcmy6qo7EBbFsyNAtdpZnlS9 5f2OTjrtiBJe2JuG/Duc6p3B/hl0LYPrwmq+x1VLxhKclq77MXUFz+8q5i8Catg3gE 9YwqxlDVWNhTeGMoye3wAp3EVf0qG6ddyQ6E/x4U= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jens Axboe , Sasha Levin Subject: [PATCH 5.10 53/93] Revert "block, bfq: honor already-setup queue merges" Date: Mon, 4 Oct 2021 14:52:51 +0200 Message-Id: <20211004125036.331527780@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211004125034.579439135@linuxfoundation.org> References: <20211004125034.579439135@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: stable@vger.kernel.org From: Jens Axboe [ Upstream commit ebc69e897e17373fbe1daaff1debaa77583a5284 ] This reverts commit 2d52c58b9c9bdae0ca3df6a1eab5745ab3f7d80b. We have had several folks complain that this causes hangs for them, which is especially problematic as the commit has also hit stable already. As no resolution seems to be forthcoming right now, revert the patch. Link: https://bugzilla.kernel.org/show_bug.cgi?id=214503 Fixes: 2d52c58b9c9b ("block, bfq: honor already-setup queue merges") Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/bfq-iosched.c | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 65c200e0ecb5..b8c2ddc01aec 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -2526,15 +2526,6 @@ bfq_setup_merge(struct bfq_queue *bfqq, struct bfq_queue *new_bfqq) * are likely to increase the throughput. */ bfqq->new_bfqq = new_bfqq; - /* - * The above assignment schedules the following redirections: - * each time some I/O for bfqq arrives, the process that - * generated that I/O is disassociated from bfqq and - * associated with new_bfqq. Here we increases new_bfqq->ref - * in advance, adding the number of processes that are - * expected to be associated with new_bfqq as they happen to - * issue I/O. - */ new_bfqq->ref += process_refs; return new_bfqq; } @@ -2594,10 +2585,6 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, { struct bfq_queue *in_service_bfqq, *new_bfqq; - /* if a merge has already been setup, then proceed with that first */ - if (bfqq->new_bfqq) - return bfqq->new_bfqq; - /* * Do not perform queue merging if the device is non * rotational and performs internal queueing. In fact, such a @@ -2652,6 +2639,9 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, if (bfq_too_late_for_merging(bfqq)) return NULL; + if (bfqq->new_bfqq) + return bfqq->new_bfqq; + if (!io_struct || unlikely(bfqq == &bfqd->oom_bfqq)) return NULL; -- 2.33.0