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 X-Spam-Level: X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 B86CAC433E6 for ; Tue, 12 Jan 2021 13:07:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6B98D2311C for ; Tue, 12 Jan 2021 13:07:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728108AbhALNGs (ORCPT ); Tue, 12 Jan 2021 08:06:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:53840 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405157AbhALM6X (ORCPT ); Tue, 12 Jan 2021 07:58:23 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 044302311D; Tue, 12 Jan 2021 12:57:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1610456259; bh=WTkWjyPZt28cdMbv407S9n9NIkZVC3x3hlm1XohUOyU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kMmXJzZtI6xVXoIEB1nVkYHpZGPh/iGqppjEkC7dWdqQjUPcgOlL7Iq4HoVlmHP2F YtsGXwGLoqU9LMjG6DACzD0y9vq468HjrKdGd7o79WgeQV0cOG85cHELGl8IzdpT4y DNhP2npDHA9QS0ZCNn6Fm/e/Hz7Vyoy3+TWaI7fGCYolG/w9XW60WigeHgkYS58pCs M/hGkovo5H2mOBCt+2K2qJT/ZLX5T1ucLRloWbpsDjGxSvy4Ite2LBkaoDk+P7uvMg K04PF9D4C2ClWk8QYN5vap+pC4LY9ShECZqPymAMipZpGLsqwZit9OfVu0syNF580q rW2WuWFShG2vg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jan Kara , Jens Axboe , Sasha Levin , linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 10/16] bfq: Fix computation of shallow depth Date: Tue, 12 Jan 2021 07:57:19 -0500 Message-Id: <20210112125725.71014-10-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210112125725.71014-1-sashal@kernel.org> References: <20210112125725.71014-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 5198ed1b36690..b7ad8ac6bb41e 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -5280,13 +5280,13 @@ 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- @@ -5296,9 +5296,9 @@ 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++) -- 2.27.0