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 B9906C83F1D for ; Thu, 10 Jul 2025 12:21:17 +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=VmWjPE7D3mF+0RXhrRJoYzPbnQ2jl43nEJ1OVAPJTsw=; b=TPrRqavwWcgSZG/SgFznOgeyxI F/kutRHvVlgXQU49MVUHDd9kMSPqEQB+7qbmE8HWjATV0KK4FibD1tr1muucmHu0ihnVCTCwMrc4e gL5u71NPzZuVPmt4s0uEhpsBmpk8Jf4qz1BIsl5R+sXsYTjHzxBfB4la359dsUVr8sZbgrtEv+k8P IoYH4HXuApeFhYuUG6LFI5Q3Sd4o0cjzdqk4FXQnT2m/7j+n2E47FaeSVEKNGsidbSg+YqD/wjhIX opuK44RH2wUiKbRIcNnx4AGnaOiY7rLKU7fU0KWGbWx0BrR/jsq0K2nTrAFe6BqpS59s6NDLKAF/U /ie+rIPQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uZqGx-0000000Bke7-3kcF; Thu, 10 Jul 2025 12:21:07 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uZozz-0000000BYXk-3ZQS for linux-arm-kernel@bombadil.infradead.org; Thu, 10 Jul 2025 10:59:31 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=VmWjPE7D3mF+0RXhrRJoYzPbnQ2jl43nEJ1OVAPJTsw=; b=QSvH7+i+KZyp2mLIqa9KeKnzA4 mJZ92k/0ULwFm/FdAzd4OQ3kGLbT0N5z9IOFdfb9jDjc/Tyi/6I1b24P4ErNTGMH4peSvitmNgLv/ iAcAM5G4NdfT21r/fGCTBE9Zn8z6C8lHYGQhaXZbBJ7vlSb/IJ+cf6ARfwEf1uL1jCFvyrF+7aI1W 1ASrbFUkb+lhPEF7+h8H7rRYkJLimKy+6euvBLC0qPcpwCx/8TeuPGM07wua5kn/6thpPpJN5nHM9 5OhgqFrBqPla0VazZTb5egiyT7OJPMta1+Ywk0ly/YJ4Dk7Gn0aFiM0VeCLzD3opdK5OLJSTwPou5 iYhkkGMw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1uZozk-00000009067-2kW4; Thu, 10 Jul 2025 10:59:17 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 6A644300125; Thu, 10 Jul 2025 12:59:13 +0200 (CEST) Date: Thu, 10 Jul 2025 12:59:13 +0200 From: Peter Zijlstra To: dan.j.williams@intel.com Cc: Jonathan Cameron , linuxarm@huawei.com, "H. Peter Anvin" , Catalin Marinas , james.morse@arm.com, linux-cxl@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, Will Deacon , Davidlohr Bueso , Yicong Yang , Yushan Wang , Lorenzo Pieralisi , Mark Rutland , Dave Hansen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Andy Lutomirski Subject: Re: [PATCH v2 0/8] Cache coherency management subsystem Message-ID: <20250710105913.GB542000@noisy.programming.kicks-ass.net> References: <20250624154805.66985-1-Jonathan.Cameron@huawei.com> <20250625085204.GC1613200@noisy.programming.kicks-ass.net> <20250625093152.GZ1613376@noisy.programming.kicks-ass.net> <20250625180343.000020de@huawei.com> <20250626105530.000010be@huawei.com> <686f506020726_1d3d10069@dwillia2-xfh.jf.intel.com.notmuch> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <686f506020726_1d3d10069@dwillia2-xfh.jf.intel.com.notmuch> 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 Wed, Jul 09, 2025 at 10:32:16PM -0700, dan.j.williams@intel.com wrote: > Theoretically there could be a threshold at which a CLFLUSHOPT loop is a > better option, but I would rather it be the case* that software CXL > cache management is stop-gap for early generation CXL platforms. So isn't the problem that CLFLUSH and friends take a linear address rather than a physical address? I suppose we can use our 1:1 mapping in this case, is all of CXL in the 1:1 map?