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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AFE8DC55184 for ; Tue, 4 Aug 2026 17:33:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=cTaqMzgFKB6BvCjR+/Mj8L7h7lMTWPAYSPCWM72+Ja8=; b=um87lcGldxWQYE0IOhgb9D7QRP +iGRrLgwOEMRPozAZ7MM/NZRxlCUNOwwuwbaJsjthowLJoeR7aTykPNOtLKH0mSjThPkJsEOakjAB BLNXX1qS8jmO/ypUk3q42tuJciobeURmpJgdVTYuAREJne+/pYniZKeC7nuf3o4iC8ctRuMmk3s/Z 2SRmmGLkmQ9+tzu8Is2LKZWPEm+E3+evJcw4xK+sDVl8L5MncAPNqa1MMVrnbmMHCkGHHMh6Z3QoT jPFh16rcq0C1/eRb31n7VZy6VB4TlwijaN4NForZPQawWbBj2/CLlHC1kO6RpC1Oe7/284smzhxJJ iMajK5RQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrJ0n-00000002VG9-3yRi; Tue, 04 Aug 2026 17:33:09 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrJ0m-00000002VFo-1Cuv for linux-arm-kernel@lists.infradead.org; Tue, 04 Aug 2026 17:33:08 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id D2080406E3; Tue, 4 Aug 2026 17:33:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF54C1F000E9; Tue, 4 Aug 2026 17:33:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785864786; bh=cTaqMzgFKB6BvCjR+/Mj8L7h7lMTWPAYSPCWM72+Ja8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=bSW/zCu2pqN1wyQJbp3qqbY97+FtE6YoCwLIy7QWHBOdR2OZssMnQJaHk84GfbWW1 At1hCpU4kt/XExzHY8E0cBRDNl7dhDPO6qhz5S6Ms7OnzeU17RRoh2dfRIoyJW/4YF 0NDu4bpq07VS85t1qupING3Z/E5e6UvDlPbRxSHIJnVLnY9rOaHMVL0frWeBdMK5tU spEURThLmhVIwXZH+Hopsk3UXu05Pd5xlehD7gA5VcXRKQXhm9U4BOe6rZuhSVrzu2 mgKRgHY4j5sGAtT2fpEg4iw8NN9Med1DIC7q4eXUL+1ug4um38g2r53s8geo49YlK8 CiXmBChnkhmKw== Date: Tue, 4 Aug 2026 18:32:47 +0100 From: "Lorenzo Stoakes (ARM)" To: Linus Torvalds Cc: "Christoph Lameter (Ampere)" , "David Hildenbrand (Arm)" , Mark Rutland , Yang Shi , Ryan Roberts , dennis@kernel.org, tj@kernel.org, urezki@gmail.com, catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Jason Gunthorpe Subject: Re: [RFC v2 PATCH 0/16] Optimize this_cpu_*() ops for non-x86 (ARM64 for this series) Message-ID: References: <0344c559-1959-4531-9265-d5a5180eb7cd@arm.com> <25d1e09b-53e4-7cd5-87db-b58437e4e690@gentwo.org> <4887267b-dc26-4c33-96ca-8dff054a0d1f@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Aug 04, 2026 at 10:01:45AM -0700, Linus Torvalds wrote: > So I'm just trying to clarify my stance - I don't hate percpu TLB > contents per se. I hate the notion of codifying them. I do worry that changing per-CPU data structures to support this is exactly codifying this (and will encourage other arches to follow suit). And I really don't think there's any way to implement this without fundamentally changing core mm or assumptions that core mm can make. -- Cheers, Lorenzo