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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 8179DC4361B for ; Thu, 17 Dec 2020 19:37:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4AD512389F for ; Thu, 17 Dec 2020 19:37:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729945AbgLQThj (ORCPT ); Thu, 17 Dec 2020 14:37:39 -0500 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:3382 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729069AbgLQThj (ORCPT ); Thu, 17 Dec 2020 14:37:39 -0500 Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Thu, 17 Dec 2020 11:36:58 -0800 Received: from [10.2.61.104] (172.20.145.6) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 17 Dec 2020 19:36:58 +0000 Subject: Re: [PATCH 18/25] btrfs: Use readahead_batch_length To: Matthew Wilcox CC: , , References: <20201216182335.27227-1-willy@infradead.org> <20201216182335.27227-19-willy@infradead.org> <20201217121246.GD15600@casper.infradead.org> <20201217134253.GE15600@casper.infradead.org> From: John Hubbard Message-ID: Date: Thu, 17 Dec 2020 11:36:58 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:84.0) Gecko/20100101 Thunderbird/84.0 MIME-Version: 1.0 In-Reply-To: <20201217134253.GE15600@casper.infradead.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL111.nvidia.com (172.20.187.18) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1608233818; bh=6rL5WMauA8+LXyGXmzjXvOTi9WOgrRuLBi9GxeFHQwQ=; h=Subject:To:CC:References:From:Message-ID:Date:User-Agent: MIME-Version:In-Reply-To:Content-Type:Content-Language: Content-Transfer-Encoding:X-Originating-IP:X-ClientProxiedBy; b=HLEYh7m+YH14H3re5sfCCvg1KTEdsatWYftLMwpfepT3/eYkHw3P3Eq4rb0XgKmqZ LVFaBzKsGC26TSljIlKDxVNpKYsW1woSLuiA6iTXMp/QIa8NZi+ywUTtcm9BAkQC/s 8XHmXqz8Rb4h7gD6Kq8Cf1krkdXne6HSCxr38AlWn/OTts/nXkmfe4/abBzoNF7asE KW8knZ0bTpYRM00SzLYZl7SvfCIe4mc70RKN8pk3wfETmtcGHSqiPmQNx2gz1qG/Nc uQmsDgx4lszWHKwxqGa9s0O7yH6k6qWxr2PhzinE0v0c1HtFalpUHoD5Rv3N1zf37U wFuZozwfh4vBA== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/17/20 5:42 AM, Matthew Wilcox wrote: > On Thu, Dec 17, 2020 at 12:12:46PM +0000, Matthew Wilcox wrote: >> ehh ... probably an off-by-one. Does subtracting 1 from contig_end fix it? >> I'll spool up a test VM shortly and try it out. > > Yes, this fixed it: > > - u64 contig_end = contig_start + readahead_batch_length(rac); > + u64 contig_end = contig_start + readahead_batch_length(rac) - 1; > Yes, confirmed on my end, too. thanks, -- John Hubbard NVIDIA