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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74B60C77B7C for ; Sat, 29 Apr 2023 19:01:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230367AbjD2TBZ (ORCPT ); Sat, 29 Apr 2023 15:01:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229512AbjD2TBX (ORCPT ); Sat, 29 Apr 2023 15:01:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 565AA1A1 for ; Sat, 29 Apr 2023 12:01:22 -0700 (PDT) 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 DD2EF60ED1 for ; Sat, 29 Apr 2023 19:01:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 91200C433D2; Sat, 29 Apr 2023 19:01:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1682794881; bh=NL8xzLoHTzsT7JTBAB6xnrlmNzu+k3vM+JbT266377Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=p0R2F8X9Nt0WOt+PaaAcHDznR51stshp5ucRSBy5rne1cGXHgnkEQ8vn3XcoQzOJ0 8AaOM8o1OE2uvXtx75UA9a2RkxBfLMHAqWMaqhRstnUgQzl0V5CunqIUSDq11IBFi0 g3y28gee+9/5bjGCTG0xMfBFQ5D5Lp1b50q5qaPgUvRkL10A1H/qkMS6aPQ7L/uCl6 99adC+8+jlpkYpnBo2bAhQbW2g4IyNUf6uxDCbfYJvi7A3fmwjlIGckgIU1thFtGQG FyH3Gv1/hjTqga4F15SJoKoQ1GXzJZdBz/Rdnbz1S/yMcSdot2HZ/uYb3BCZVydxFa GMbPbwX5oJnFQ== Date: Sat, 29 Apr 2023 22:01:07 +0300 From: Mike Rapoport To: Catalin Marinas Cc: "Justin M. Forbes" , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, jmforbes@linuxtx.org, Andrew Morton Subject: Re: [PATCH] Revert arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER Message-ID: References: <20230428153646.823736-1-jforbes@fedoraproject.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 28, 2023 at 06:01:30PM +0100, Catalin Marinas wrote: > + Mike and Andrew > > On Fri, Apr 28, 2023 at 10:36:45AM -0500, Justin M. Forbes wrote: > > While the ARCH_FORCE_MAX_ORDER changes clarified the descriptions quite > > a bit, the aarch64 specific change moved this config to sit behind > > CONFIG_EXPERT. This becomes problematic when distros are setting this to > > a non default value already. Pushing it behind EXPERT where it was not > > before will silently change the configuration for users building with > > oldconfig. If distros patch out if EXPERT downstream, it still creates > > problems for users testing out upstream patches, or trying to bisect to > > find the root of problem, as the configuration will change unexpectedly, > > possibly leading to different behavior and false results. > > > > Whem I asked about reverting the EXPERT, dependency, I was asked to add Nit: When > > the ranges back. > > > > This essentially reverts commit 34affcd7577a232803f729d1870ba475f294e4ea > > > > Signed-off-by: Justin M. Forbes > > Cc: Catalin Marinas > > --- > > arch/arm64/Kconfig | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index b1201d25a8a4..dae18ac01e94 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -1516,9 +1516,11 @@ config XEN > > # 16K | 27 | 14 | 13 | 11 | > > # 64K | 29 | 16 | 13 | 13 | > > config ARCH_FORCE_MAX_ORDER > > - int "Order of maximal physically contiguous allocations" if EXPERT && (ARM64_4K_PAGES || ARM64_16K_PAGES) > > + int "Order of maximal physically contiguous allocations" if ARM64_4K_PAGES || ARM64_16K_PAGES > > default "13" if ARM64_64K_PAGES > > + range 11 13 if ARM64_16K_PAGES > > default "11" if ARM64_16K_PAGES > > + range 10 15 if ARM64_4K_PAGES > > default "10" > > help > > The kernel page allocator limits the size of maximal physically > > The revert looks fine to me: > > Acked-by: Catalin Marinas > > For the record, the original discussion: > > Link: https://lore.kernel.org/r/CAFxkdAr5C7ggZ+WdvDbsfmwuXujT_z_x3qcUnhnCn-WrAurvgA@mail.gmail.com I'm not really happy about this revert because MAX_ORDER is not something that should be changed easily. But since hiding it behind EXPERT would silently change lots of existing builds, I won't object. Still, I never got the answer _why_ Fedora/RHEL configs use non-default value. Quite possible something else needs to be fixed rather than having overgrown MAX_ORDER. -- Sincerely yours, Mike.