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 3C5BFC77B7E for ; Tue, 2 May 2023 14:21:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234421AbjEBOVY (ORCPT ); Tue, 2 May 2023 10:21:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38958 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233849AbjEBOVW (ORCPT ); Tue, 2 May 2023 10:21:22 -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 178F395 for ; Tue, 2 May 2023 07:21:21 -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 A6A986241A for ; Tue, 2 May 2023 14:21:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0661CC433EF; Tue, 2 May 2023 14:21:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683037280; bh=asliVNBY/st5F3nTupJNy+o9LWLCvC1CAL3wn6OSEf8=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=G48dLF53wNhKD4VSzQeUVDntT+bpVgE0ddCvZzRLsfLnZabL0FZcPNTrfe03o2XPn absPYIgQpsXRRj/5XwY+eWh8uU7wb0mNCCGn/PefsS7Vd1rSI4XQSyESo07hHJWwi+ +F1A5OsmeUN+xZHnf9ptQDdFYkSI7i6QwuFgZwabCRQ34ZDoGFG9blCVb6Z5wH37Nh 0s1pBR+GIHL2s6XlhG/f4pu2c7HeqySpvHN0vJKodxvbPpWNV7iQDixnBxnalIzJ++ NtZh8ADCyI2DUBXVe5etrnVU/19hXY504QcV6FfU6rg8dmu/2D9qmwfYrh5+wimoNd ejpkDR50KDSfw== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1ptqsX-00CVEM-JR; Tue, 02 May 2023 15:21:17 +0100 Date: Tue, 02 May 2023 15:21:17 +0100 Message-ID: <86pm7ihl0i.wl-maz@kernel.org> From: Marc Zyngier To: Justin Forbes , Catalin Marinas Cc: Mike Rapoport , 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 In-Reply-To: References: <20230428153646.823736-1-jforbes@fedoraproject.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/28.2 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: jforbes@fedoraproject.org, catalin.marinas@arm.com, rppt@kernel.org, will@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, jmforbes@linuxtx.org, akpm@linux-foundation.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 02 May 2023 15:07:41 +0100, Catalin Marinas wrote: >=20 > On Mon, May 01, 2023 at 04:24:38PM -0500, Justin Forbes wrote: > > On Sat, Apr 29, 2023 at 11:02=E2=80=AFPM Mike Rapoport wrote: > > > Why the default MAX_ORDER was not acceptable on arm64 server machines= but > > > it is fine on, say, x86 and s390? > > > I'm not asking how you made it possible in Fedora and RHEL, I'm askin= g why > > > did you switch from the default order at all. > >=20 > > Because the MAX_ORDER on aarch64 with 4K pages is more tuned to the > > needs of the average edge client, not so much those of a server class > > machine. And I get it, I would say well over 90% of the Fedora users > > running aarch64 are indeed running on a rPi or similar with a small > > memory footprint, and workloads which match that. But we do support > > and run a 4K page size aarch64 kernel on proper server class hardware, > > running typical server workloads, and RHEL has a lot more users in the > > server class than edge clients. RHEL could probably default to 64K > > pages, and most users would be happy with that. Fedora certainly could > > not.=20 >=20 > I was talking to Marc Zyngier earlier and he reckons the need for a > higher MAX_ORDER is the GIC driver ITS allocation for Thunder-X. I'm > happy to make ARCH_MAX_ORDER higher in defconfig (12, 13?) if > CONFIG_ARCH_THUNDER. Mobile vendors won't enable this platform. In any case, I'd like to know exactly *what* requires it. The only platform I know would benefit from this is the old TX1, but this machine is more a boat anchor than a real server. M. --=20 Without deviation from the norm, progress is not possible.