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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E952EC27C53 for ; Wed, 12 Jun 2024 18:51:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7E2316B00A6; Wed, 12 Jun 2024 14:51:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 792776B00A7; Wed, 12 Jun 2024 14:51:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 659C86B00A8; Wed, 12 Jun 2024 14:51:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 486F86B00A6 for ; Wed, 12 Jun 2024 14:51:00 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id DAC2B41891 for ; Wed, 12 Jun 2024 18:50:59 +0000 (UTC) X-FDA: 82223128638.03.854EA9F Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf01.hostedemail.com (Postfix) with ESMTP id 94E6740004 for ; Wed, 12 Jun 2024 18:50:57 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=UN40XRk9; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1718218258; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=SnTD+YzDcFdeMAvSsaXVlZcl9N1crAVDMcpCBvbsy4M=; b=uy+06OTBDc+zrjUwQRZ+X1EiWz91MVACgw8x9ZFzdWifMALJQzVO8grCYyaU8breQN80Kf Fq1VtyGYKY7uXpxF2FUdY4nS7+7/qqoDJ9pN3+xOfJa9egDJEMTOCnTu1oslMPL/+iRSVe b7/24sgN0dmanf2ZyZP0hx8BOk6SNAY= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=UN40XRk9; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1718218258; a=rsa-sha256; cv=none; b=Ur2ejvBmWY6IgZHYNiKqiXyUITHabQ908B+Lv7LoN2tcwl/Xn3ksXv1e1MtU3gnDccEdDq F1VrN0qtD8HlbOTS0X8CzfawfN+dmKpXTBa8yiqIpLM9Y4btpVvIvK6cLA7MDyKm6hMhN3 YXP1hR4zuUfU10bl+5fml49JiFUcXpM= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=SnTD+YzDcFdeMAvSsaXVlZcl9N1crAVDMcpCBvbsy4M=; b=UN40XRk98RsgoJc9yo1fssXg4B rhAiDU4piBR+yp7MAQSmFafqrEBApb5mYlwjE9CykOkoWUBWGqMhKGrMqUoLS2TO7EVdzFDEmZfMY gr2/B6BPuy6EjyIothSFx4I2t0byuYkB772tm/NlqmDkm24/i1888acz6GDNgWbjgGNJKQRbPkuAN q2tsfM8iX4s+cOyTSytKQtrDOO8tvCWxya3zpclY4sBqq6LWeTY4iJg8A189S9xb3oPARsa421sAY FOvNO0J/v+GC7qJRf9g3xvGtqGWhkTXdioqI/qORq91Fe43olNz3Va+hORnhpcPi0qDEKOS8hlym8 nxcCddog==; Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1sHT3Z-0000000EzSY-0Y2E; Wed, 12 Jun 2024 18:50:49 +0000 Date: Wed, 12 Jun 2024 19:50:49 +0100 From: Matthew Wilcox To: "Pankaj Raghav (Samsung)" Cc: david@fromorbit.com, djwong@kernel.org, chandan.babu@oracle.com, brauner@kernel.org, akpm@linux-foundation.org, mcgrof@kernel.org, linux-mm@kvack.org, hare@suse.de, linux-kernel@vger.kernel.org, yang@os.amperecomputing.com, Zi Yan , linux-xfs@vger.kernel.org, p.raghav@samsung.com, linux-fsdevel@vger.kernel.org, hch@lst.de, gost.dev@samsung.com, cl@os.amperecomputing.com, john.g.garry@oracle.com Subject: Re: [PATCH v7 04/11] readahead: allocate folios with mapping_min_order in readahead Message-ID: References: <20240607145902.1137853-1-kernel@pankajraghav.com> <20240607145902.1137853-5-kernel@pankajraghav.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240607145902.1137853-5-kernel@pankajraghav.com> X-Rspamd-Queue-Id: 94E6740004 X-Rspam-User: X-Rspamd-Server: rspam09 X-Stat-Signature: 7amb1nqjsnkig3e5waaf4g47oqsfjh7m X-HE-Tag: 1718218257-462944 X-HE-Meta: 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 IHHDu7D5 +frdabBFu1QXjt3Rf2kTl7vFdUzvnIJTmzI2D9kyQiRswSFZA+Xcm5fa7miK/GhI6a+NkpAVk+AwakajpMoYTCElkkGYjGqXdJHzvv2qvVrZm6/bb/jSlIL6iTkCsctyZhsaLI9vOaY3p0ALiupXiHUeFy9A+yUbzoeMGrcBgUTSZimGLVDBmZ9owWQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Jun 07, 2024 at 02:58:55PM +0000, Pankaj Raghav (Samsung) wrote: > @@ -230,7 +247,9 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, > struct folio *folio = xa_load(&mapping->i_pages, index + i); > int ret; > > + Spurious newline > if (folio && !xa_is_value(folio)) { > + long nr_pages = folio_nr_pages(folio); Hm, but we don't have a reference on this folio. So this isn't safe. > @@ -240,12 +259,24 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, > * not worth getting one just for that. > */ > read_pages(ractl); > - ractl->_index += folio_nr_pages(folio); > + > + /* > + * Move the ractl->_index by at least min_pages > + * if the folio got truncated to respect the > + * alignment constraint in the page cache. > + * > + */ > + if (mapping != folio->mapping) > + nr_pages = min_nrpages; > + > + VM_BUG_ON_FOLIO(nr_pages < min_nrpages, folio); > + ractl->_index += nr_pages; Why not just: ractl->_index += min_nrpages; like you do below?