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 BBD44C77B73 for ; Wed, 19 Apr 2023 11:05:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E11D98E0002; Wed, 19 Apr 2023 07:05:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DC0088E0001; Wed, 19 Apr 2023 07:05:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CAF708E0002; Wed, 19 Apr 2023 07:05:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id BAE018E0001 for ; Wed, 19 Apr 2023 07:05:40 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 8D3741201E7 for ; Wed, 19 Apr 2023 11:05:40 +0000 (UTC) X-FDA: 80697860040.26.7E1D454 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf29.hostedemail.com (Postfix) with ESMTP id DF681120027 for ; Wed, 19 Apr 2023 11:05:37 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1681902338; 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; bh=Yh7nm9G6tXNKNhn1qv/ac7gRo2SwzJ3+YuDLIEM5lrE=; b=GOAFrQD2qt0fimgiwT4QuEj5aAx6O6UJ92mREmW2/CPyMpJow4zs6KewQT6yxOykZ6XhV2 I601vUeCg2yLfTrTzsIbX2eFp26WEnoTj91eOSdIjlUN79sSiYzP9Ik0AyWxb9rtm6n4Ob 4xRv+rfNqjfc+a4qcwdK/91gaBQE7XE= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=none; spf=pass (imf29.hostedemail.com: domain of cmarinas@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=cmarinas@kernel.org; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=arm.com (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1681902338; a=rsa-sha256; cv=none; b=CD9Z8x8Crttbwtjm2BSacZZ8QTW4uuYaFI8vCLxnxz2ClZSFuwSjTPezyISZluo8WQJEBj NNg+m7mOAYqZ08fYGh/MQmOw1XltWdRWlKQjGGPTMZudral6MkcHEdUXQhZcnfv9G1Pg+F 3eVmepKLrfBfaRAf+9xrCXw829+D+ho= 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 BF6946223F; Wed, 19 Apr 2023 11:05:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C58FEC433EF; Wed, 19 Apr 2023 11:05:31 +0000 (UTC) Date: Wed, 19 Apr 2023 12:05:28 +0100 From: Catalin Marinas To: Andrew Morton Cc: Justin Forbes , Mike Rapoport , Arnd Bergmann , Christophe Leroy , "David S. Miller" , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , John Paul Adrian Glaubitz , "Kirill A. Shutemov" , Max Filippov , Michael Ellerman , Rich Felker , Russell King , Will Deacon , Yoshinori Sato , Zi Yan , linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mm@kvack.org, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org Subject: Re: [PATCH v3 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER Message-ID: References: <20230325060828.2662773-1-rppt@kernel.org> <20230325060828.2662773-3-rppt@kernel.org> <20230418150557.ea8c87c96ec64c899c88ab08@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230418150557.ea8c87c96ec64c899c88ab08@linux-foundation.org> X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: 391yw1u8tpfj138zu5gsdwoezej1tkte X-Rspamd-Queue-Id: DF681120027 X-HE-Tag: 1681902337-813817 X-HE-Meta: U2FsdGVkX1+jfe9RHezBxNB19RpTEnwgvs5en9bygN/1RzXjW/0w/TtNleIpf8T+uv8qAuqg9feGzPnn7xD076f106mQXSw/VCxVSG135s651Tc2qa8OM5YfkgiZrONYjhPmlZLq6WJK+oDhSjwboScBOqWIvRd3V4fEAz1ofnXS9U4EOJcaY894kAdhCpPmQXfZut8pS0y/JTx7mNN715BCnHqsVKDU2JkWVQlb78KLvqpBOwE19GaCPFQmSvGRfpqt+tnXn20nY3EF+djtYYQMDxQz8Ft8bWUoziPjjbsGKSk4QbcdQE1z9NsJ6mwFbWE8HsqiazIiQnyfQr8RsifjFTyqewynZJixru/KrNfqNfdxfaJt6v6abAJb1Rjm+UZihNieeYiyHxQnsOfsXW70jvwHs1o5TvhvjlZ93ggU6kFxV5QvcYvYI4hvwZu5uwSYHsUkJCqtYZGta4KjaL75Vs1r7sv+o+oPllJHcYk+ZEPr5L+wryiMdvcfeWyhlIS2dG5RNF17FawWa5SRRX9UOTlOTleFA5mrOAMylFJ6XTQ11NffS+dDKkOtpqCilMrB0cq2XJ40OWilWQUAve1CfxkfEGo9lNQz+kDN9xoBRZ7Zj9qfmZGNhCkgSNqSEfne8QCki13iRTQ0zDQZ3bC833zWCxppPe7U9kXC4CEYTxx6MdauMjwPcG2e7HLMG4D19y4CcRUU6iCME9eIG5vSZy/QbhZlHexFC3KQIfefOyx7sjRUgOiE+f1MV4Gd1+KXDtcyxpccI+R6q9nXEojyahqjWWyfcM3JHLfUqm0v1qKXxO6Vewx0rA5uxHMf7g4+MUNUVPgKnBjyZPQAEutKVNvDiOfsTTKAJGa5hMhfPR9fVM27Tt388D2xwdAGOTb2YMBcffMQbaI7A+N3qOx9yawjG7pucMzLoav3umLui/8KgoTjR7P5mc64nOKx+OJQyDUou5nniW3CdST ot1eNL7+ 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 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: On Tue, Apr 18, 2023 at 03:05:57PM -0700, Andrew Morton wrote: > On Wed, 12 Apr 2023 18:27:08 +0100 Catalin Marinas wrote: > > > It sounds nice in theory. In practice. EXPERT hides too much. When you > > > flip expert, you expose over a 175ish new config options which are > > > hidden behind EXPERT. You don't have to know what you are doing just > > > with the MAX_ORDER, but a whole bunch more as well. If everyone were > > > already running 10, this might be less of a problem. At least Fedora > > > and RHEL are running 13 for 4K pages on aarch64. This was not some > > > accidental choice, we had to carry a patch to even allow it for a > > > while. If this does go in as is, we will likely just carry a patch to > > > remove the "if EXPERT", but that is a bit of a disservice to users who > > > might be trying to debug something else upstream, bisecting upstream > > > kernels or testing a patch. In those cases, people tend to use > > > pristine upstream sources without distro patches to verify, and they > > > tend to use their existing configs. With this change, their MAX_ORDER > > > will drop to 10 from 13 silently. That can look like a different > > > issue enough to ruin a bisect or have them give bad feedback on a > > > patch because it introduces a "regression" which is not a regression > > > at all, but a config change they couldn't see. > > > > If we remove EXPERT (as prior to this patch), I'd rather keep the ranges > > and avoid having to explain to people why some random MAX_ORDER doesn't > > build (keeping the range would also make sense for randconfig, not sure > > we got to any conclusion there). > > Well this doesn't seem to have got anywhere. I think I'll send the > patchset into Linus for the next merge window as-is. Please let's take > a look at this Kconfig presentation issue during the following -rc > cycle. That's fine by me. I have a slight preference to drop EXPERT and keep the ranges in, especially if it affects current distro kernels. Debian seems to enable EXPERT already in their arm64 kernel config but I'm not sure about the Fedora or other distro kernels. If they don't, we can fix/revert this Kconfig entry once the merging window is closed. -- Catalin