From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD2912264C7 for ; Tue, 4 Aug 2026 17:33:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785864791; cv=none; b=HtROk5ZsVBCOfhiwrqGgsV1+Kurbr2XcPoOvdxptHmE0R4QRZTIIkTFr3fjrZxFCh8/tvobLeI1XjCTpYIvuztPLa5NjdQ0m3LRPw1oyRYEzP8cl8kYXxz05oOqfUVyVKH14xuUxnxDlIu6Cgjy6euZRvtPAwU1qJBK/452RU5w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785864791; c=relaxed/simple; bh=cTaqMzgFKB6BvCjR+/Mj8L7h7lMTWPAYSPCWM72+Ja8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Qer9na+3hnvCxSgiDJoUCdjyfB9tmhuJosTl5rdlWauXG29taTusHQGjIhilyTy1YBtd8mft/9rmy1/xFSlPoTz9ulpNKvbe+Kk2qrAZ7lKL+XLm/DL6HSCr7YP0W0RDK1f/aITbdjKuk5GlB60l9dJ85aN8DMSEPpb3isA0Vu0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bSW/zCu2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bSW/zCu2" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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