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 4F89EC4167B for ; Mon, 4 Dec 2023 17:17:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C45E06B0277; Mon, 4 Dec 2023 12:17:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BF6116B0281; Mon, 4 Dec 2023 12:17:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AE46D6B028B; Mon, 4 Dec 2023 12:17:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 9F44D6B0277 for ; Mon, 4 Dec 2023 12:17:41 -0500 (EST) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 6BE4480311 for ; Mon, 4 Dec 2023 17:17:41 +0000 (UTC) X-FDA: 81529792722.14.F7FD84E Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf13.hostedemail.com (Postfix) with ESMTP id 203352002C for ; Mon, 4 Dec 2023 17:17:37 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=NQZ6lFKU; dmarc=none; spf=none (imf13.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701710259; 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=Qih1MMcygv+L/VjoGaoIvgl1mwsYXvUSRf8N7krWJcs=; b=s0yH99xaWum6VFI0UaE92pXLvaBZt9YU9wAGbgiSsU5lD+KqLcvnpxu3iG3U/512msMw4V LcUlAWMXsGsCFojoCqcguRPZoEg9RAbm07fuPaztZPPrugIPNZAckVu0sz0oAXHVvP5WWd eaUEmM/vCp37s265T4qcTht9pnYrCGw= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=NQZ6lFKU; dmarc=none; spf=none (imf13.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701710259; a=rsa-sha256; cv=none; b=E23yKQdKN9mn47hgA+tNIo+6SkdOccmcnQHR7XfXuk7QfNmP9Wi40hZAWPUgtRx+/goaOn 0+EbmeOn7TZrzFKAbiSgiEIGQ+4yQo9Q/MO1dHuwnqFRd1UUiC3g8OGkJ59CF/TSUga60Z QSgSmwwX8dUD5SFJnPZuVRXVIf2phqA= 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=Qih1MMcygv+L/VjoGaoIvgl1mwsYXvUSRf8N7krWJcs=; b=NQZ6lFKU3EFNi6+S3miZtMSyOz Fr02q5Q3nuxjCQhTDjXdY3FfL3llkEaulnLhWL2cbHZv2K78ttlaC2bvREaQbCzItgDF8ONq9OjLq EF/2GUAIv6X6HZLRBwQTVDkhOgTVlTJOVzteqTTJgbY3kmj0hKJZ/eJHVMy/aUGVWs0WHpSKfOHrq bWxcS7qQqOp9hpR9oHZaMhOlffbsgkl3MjQF8aemXHLnotr0ExpAUf+NN6R9xxXpdiXjGkV0z0Ii/ 0fqKAnFzUE7Wa6RM2GUib7izMNUNfAaKm8ZpEma9MfnMogEky3/hUegymZKYhvaVOITZB3stY4fbg nCh2F66w==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1rACZW-000ssm-4o; Mon, 04 Dec 2023 17:17:30 +0000 Date: Mon, 4 Dec 2023 17:17:30 +0000 From: Matthew Wilcox To: David Hildenbrand Cc: Viacheslav Dubeyko , Linux FS Devel , linux-mm@kvack.org, Hugh Dickins , "Kirill A. Shutemov" Subject: Re: Issue with 8K folio size in __filemap_get_folio() Message-ID: References: <22d5bd19-c1a7-4a6c-9be4-e4cb1213e439@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <22d5bd19-c1a7-4a6c-9be4-e4cb1213e439@redhat.com> X-Rspamd-Queue-Id: 203352002C X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: tiagg7hj91yqk8ytcs5cqydjxkofoctx X-HE-Tag: 1701710257-776698 X-HE-Meta: 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 Zg9zDb0V 9tVgYJPmnmHT6eexmrLyVAJBVZTbkdw5tU/LsEKIAkyqAq1oRKqambUCIQ4aOxpAgncFXes9u4LAergNSUI56Z/FJEvkRsuFd5kJ5AWxOIzB6KPooe4lRZcx2uzpu7pRZ2hGh5esWjRUWk1aZpODQ4G5B/GhvepxqCKffXo8GHY6Gd3u7PXTL90p16DRRn1nWJmQYNle+Dnvhry1ry55fEicqBRiWhS/Pecdo2pIucjgvOzzCf6Dhf7w8qRrKsU6vRXaYW8r6DhTgXREnkPH8PJSiUyIsR4Xnb3Wl 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 Mon, Dec 04, 2023 at 04:09:36PM +0100, David Hildenbrand wrote: > I think for the pagecache it should work. In the context of [1], a total > mapcount would likely still be possible. Anything beyond that likely not, if > we ever care. I confess I hadn't gone through your patches. https://lore.kernel.org/all/20231124132626.235350-8-david@redhat.com/ is the critical one. It's actually going to walk off the end of order-2 folios today (which we'll create, eg with XFS). You can put _rmap_val0 and _rmap_val1 in page2 and _rmap_val2-5 in page3 to fix this. Once we're allocating order-1 folios, I think you can avoid this scheme and just check page0 and page1 mapcounts independently.