From patchwork Mon Jan 18 11:34:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "gregkh@linuxfoundation.org" X-Patchwork-Id: 366000 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 9E53AC43381 for ; Mon, 18 Jan 2021 19:08:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 675A0224B8 for ; Mon, 18 Jan 2021 19:08:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390532AbhARLjS (ORCPT ); Mon, 18 Jan 2021 06:39:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:33392 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390513AbhARLjF (ORCPT ); Mon, 18 Jan 2021 06:39:05 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E217E223E8; Mon, 18 Jan 2021 11:38:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610969917; bh=/TpIWJHKIKeo3ag1s8Vm+eQe+JfpDBJA6BfFKVg4ZZY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=C8S70ab99i06CgWeBbdlEvd4k+yKq2zmO+HINKv5gk6JswSyOJ6X6eOLhc9b1v6nD aO9jokbM1uqg1u9EgWC+yHrTmF+DiV547j7naS433fQyRtGhx5bd6aPwFBuDcNEtEc sArEJkAngYvgwI2Nu5du8HOrySVzCGax3oomYi6Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Jens Axboe , Sasha Levin Subject: [PATCH 5.4 37/76] bfq: Fix computation of shallow depth Date: Mon, 18 Jan 2021 12:34:37 +0100 Message-Id: <20210118113342.758147366@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210118113340.984217512@linuxfoundation.org> References: <20210118113340.984217512@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jan Kara [ Upstream commit 6d4d273588378c65915acaf7b2ee74e9dd9c130a ] BFQ computes number of tags it allows to be allocated for each request type based on tag bitmap. However it uses 1 << bitmap.shift as number of available tags which is wrong. 'shift' is just an internal bitmap value containing logarithm of how many bits bitmap uses in each bitmap word. Thus number of tags allowed for some request types can be far to low. Use proper bitmap.depth which has the number of tags instead. Signed-off-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/bfq-iosched.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index ba32adaeefdd0..7d19aae015aeb 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -6320,13 +6320,13 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd, * limit 'something'. */ /* no more than 50% of tags for async I/O */ - bfqd->word_depths[0][0] = max((1U << bt->sb.shift) >> 1, 1U); + bfqd->word_depths[0][0] = max(bt->sb.depth >> 1, 1U); /* * no more than 75% of tags for sync writes (25% extra tags * w.r.t. async I/O, to prevent async I/O from starving sync * writes) */ - bfqd->word_depths[0][1] = max(((1U << bt->sb.shift) * 3) >> 2, 1U); + bfqd->word_depths[0][1] = max((bt->sb.depth * 3) >> 2, 1U); /* * In-word depths in case some bfq_queue is being weight- @@ -6336,9 +6336,9 @@ static unsigned int bfq_update_depths(struct bfq_data *bfqd, * shortage. */ /* no more than ~18% of tags for async I/O */ - bfqd->word_depths[1][0] = max(((1U << bt->sb.shift) * 3) >> 4, 1U); + bfqd->word_depths[1][0] = max((bt->sb.depth * 3) >> 4, 1U); /* no more than ~37% of tags for sync writes (~20% extra tags) */ - bfqd->word_depths[1][1] = max(((1U << bt->sb.shift) * 6) >> 4, 1U); + bfqd->word_depths[1][1] = max((bt->sb.depth * 6) >> 4, 1U); for (i = 0; i < 2; i++) for (j = 0; j < 2; j++)