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 8521EC77B7C for ; Fri, 12 May 2023 03:38:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D81A96B0071; Thu, 11 May 2023 23:38:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D31D66B0074; Thu, 11 May 2023 23:38:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BF9136B0075; Thu, 11 May 2023 23:38:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id AD05C6B0071 for ; Thu, 11 May 2023 23:38:31 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 76532A0350 for ; Fri, 12 May 2023 03:38:31 +0000 (UTC) X-FDA: 80780195622.26.9654058 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf25.hostedemail.com (Postfix) with ESMTP id AFFEDA000B for ; Fri, 12 May 2023 03:38:28 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=U4rplEw0; spf=pass (imf25.hostedemail.com: domain of rppt@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=none) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1683862708; 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=ZDvCkpWodX3oBcNkPNQodjjfJ0U0BF7pqW/rMs5nTEI=; b=sivbfrM+geChKnwy3t06io4en/y7gl6btWqca38mzRS4R/8umpjF5yKARZtHyBtcnLMTx8 /oaZFQuo72G8xmM9Q/YjFzh/WHO3XLMhIp5Bv8vectcclhjEb9v/Bs16Ps1/54rmdDAJQj 8BNj21U7ORsu77hJHn4Iq1ylV22aNTk= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1683862708; a=rsa-sha256; cv=none; b=iiL/SY2G9lfDHCTfe+Tl8BjeBQMEbJD+qsdD9wFA22DRKbaHBaStKgST+dRo8dVdW53bbF 3XI0O/fErPlRjeh+vEB5j7lbOFbe70KBTUFNRopGBFF/zKwJNB0BNuxAlJQUmFxqG1D59q SaMpN33fYsl9qlzB7e96FXv7ASXmOnk= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=U4rplEw0; spf=pass (imf25.hostedemail.com: domain of rppt@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=rppt@kernel.org; dmarc=pass (policy=none) header.from=kernel.org Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9A6A964D9A; Fri, 12 May 2023 03:38:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15A0DC433EF; Fri, 12 May 2023 03:38:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683862707; bh=Q7pZ6HkRh3PVDzBCV74mB+fwpBcm2L4Wrr7Gj6KO6ZA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=U4rplEw0qMOGxowZ1loQ7IR10mVPR+gkIHrN9H2/CYQigVdydLPavay7G++a7nk75 jDhpGXpsFo8grDqyj+dAD0bRHJYnhZ3zC9JzvBPFC3B2RpUt1tYfAWrn3pIHyEvUc0 m+plA03PmuYT+NcYOD6DwNQyNX3nG8GNV7/Tz7bjzisl+mJN6FAg46r36holy/6HO4 6GEsQAkOKAoidlLLVYOcRtmzSHojiofTEI1BfDjbKkAJM3vujpQ7oWR4AovPMspdwk AfdZmFHnb8dcLpWYTKW3v5BTK8ry629pZRiCq4rIBS69MISbPUUJXyByuj5gGgwTNw bDNRPX9IyrHYA== Date: Thu, 11 May 2023 20:38:24 -0700 From: Mike Rapoport To: Matthew Wilcox Cc: Hugh Dickins , Andrew Morton , Mike Kravetz , "Kirill A. Shutemov" , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Greg Ungerer , Michal Simek , Thomas Bogendoerfer , Helge Deller , John David Anglin , "Aneesh Kumar K.V" , Michael Ellerman , Alexandre Ghiti , Palmer Dabbelt , Heiko Carstens , Christian Borntraeger , Claudio Imbrenda , John Paul Adrian Glaubitz , "David S. Miller" , Chris Zankel , Max Filippov , Peter Zijlstra , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Michel Lespinasse Subject: Re: [PATCH 00/23] arch: allow pte_offset_map[_lock]() to fail Message-ID: <20230512033824.GF4135@kernel.org> References: <77a5d8c-406b-7068-4f17-23b7ac53bc83@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: AFFEDA000B X-Rspam-User: X-Rspamd-Server: rspam06 X-Stat-Signature: ooecoiyo6c17oho9gt5n1mje7asupbsy X-HE-Tag: 1683862708-263934 X-HE-Meta: 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 uWx2bo4s iSRTXY33dOwQIIUayYGV2wW/FZWOChK4tRXKnAab/RTBEG8VhJHfVkvR0/bOF4U85l1d66bRkCujBlVZjoNy3+fIPzoAnC7Ga3wWUdSmVhG6v+0y4qeXc6CLB06lv8k2LnSDng8ptO7GE7uBdJdrXGq/hJTO5UxvXlnUi1WpsKOf8cKGF79ockkF849rI6DtYL/PYnd2Zl4dq9mDzrK2NcZDNplxL6StVii9IEunxy7QmNItKyZYpLRmp7D8Ky4gMhU89cn5oii3DLeRgtpPCMrvdQSF5uMNK5V/4LiI0x16hyidodOBZZoH8HHAgDvcWla6wbfyh8tP/VwL/EIpE/5/mhg== 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: Hi, On Thu, May 11, 2023 at 03:02:55PM +0100, Matthew Wilcox wrote: > On Wed, May 10, 2023 at 09:35:44PM -0700, Hugh Dickins wrote: > > On Wed, 10 May 2023, Matthew Wilcox wrote: > > > > I don't really understand why you're going down a remove-CONFIG_HIGHPTE > > route: I thought you were motivated by the awkardness of kmap on large > > folios; but I don't see how removing HIGHPTE helps with that at all > > (unless you have a "large page tables" effort in mind, but I doubt it). > > Quite right, my primary concern is filesystem metadata; primarily > directories as I don't think anybody has ever supported symlinks or > superblocks larger than 4kB. > > I was thinking that removing CONFIG_HIGHPTE might simplify the page > fault handling path a little, but now I've looked at it some more, and > I'm not sure there's any simplification to be had. It should probably > use kmap_local instead of kmap_atomic(), though. Removing CONFIG_HIGHPTE will drop several lines and will allow to get rid of custom __pte_alloc_one on x86. -- Sincerely yours, Mike.