From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753758AbdF0Uzb (ORCPT ); Tue, 27 Jun 2017 16:55:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:44500 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752914AbdF0UzY (ORCPT ); Tue, 27 Jun 2017 16:55:24 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D802B214E2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=helgaas@kernel.org Date: Tue, 27 Jun 2017 15:55:21 -0500 From: Bjorn Helgaas To: Thomas Gleixner Cc: Andi Kleen , LKML , x86@kernel.org, Peter Anvin , Borislav Petkov , Peter Zijlstra , Stephane Eranian , linux-pci@vger.kernel.org Subject: Re: [patch 0/7] x86/pci: Switch to lockless ECAM configuration mode Message-ID: <20170627205521.GA764@bhelgaas-glaptop.roam.corp.google.com> References: <20170316215002.726697858@linutronix.de> <20170613002536.GA21242@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [+cc linux-pci] On Thu, Jun 22, 2017 at 12:28:09AM +0200, Thomas Gleixner wrote: > Andi, > > On Mon, 12 Jun 2017, Andi Kleen wrote: > > On Thu, Mar 16, 2017 at 10:50:02PM +0100, Thomas Gleixner wrote: > > > Andi reported that the Intel Uncore performance monitoring suffers from the > > > global pci_lock which protects the generic PCI config space accessors. > > > > > > This lock can be removed on X86 because all architecture specific config > > > space accessors are either serialized by a seperate lock or can be > > > converted to have their own locking. The mmconfig based access (ECAM) does > > > not require serialization at the config read/write level because the access > > > is a simple byte/word/dword read from or write to the memory mapped > > > configuration space. In that case the lock does not provide any more > > > protection than the hardware provides already. > > > > > > The series converts the CE4100 PCI low level accessors to use the x86 > > > specific pci_config_lock and implements the switch over to lockless ECAM > > > configureation space accesors when the system is capable. > > > > What's the status of this patch series? The lock contention > > problem is still there. > > Just rechecked. It still applies and boots (patch 6/7) dropped. > > If Bjorn has no objections I can route it through tip tomorrow. Sorry for the delay. I use patchwork as my to-do list, and it only looks at linux-pci. This series wasn't posted there, so I didn't see it until now. I have a couple trivial comments but I think it looks great overall. Here's my ack if you want to apply it via tip: Acked-by: Bjorn Helgaas Bjorn