From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.136]:41798 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752398AbcHIRhJ (ORCPT ); Tue, 9 Aug 2016 13:37:09 -0400 Date: Tue, 9 Aug 2016 12:36:33 -0500 From: Bjorn Helgaas To: Keith Busch Cc: linux-pci@vger.kernel.org, Bjorn Helgaas , Wei Zhang , Jens Axboe Subject: Re: [PATCH 0/3] Limiting pci access requests Message-ID: <20160809173633.GF27301@localhost> References: <1470683667-28418-1-git-send-email-keith.busch@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1470683667-28418-1-git-send-email-keith.busch@intel.com> Sender: linux-pci-owner@vger.kernel.org List-ID: Hi Keith, On Mon, Aug 08, 2016 at 01:14:24PM -0600, Keith Busch wrote: > We observe that error handling and device hot removal creates many > unnecessary config and memory accesses to devices, some of which are not > even present. While we expect command processing to proceed, we observe > on various platforms that the unnecessary accesses create instability > with hardware performing completion synthesis, and slows down handling > of such error events as well as normal IO processing. Is there some hot removal path that we've suddenly starting exercising more than we used to? Can you give us any details of that? I'm wondering if there are any more generic fixes we can make. These patches seem good, but a little piece-meal, so it feels like there could be more places where we trip over similar issues. > This patch series aims to reduce unnecessary accesses. > > Keith Busch (3): > pcie: Don't search capabilities on removed devices > pci/msix: Skip disabling removed devices > pcie/aer: Cache capability position > > drivers/pci/msi.c | 5 +++++ > drivers/pci/pci.c | 2 +- > drivers/pci/pcie/aer/aerdrv.c | 38 +++++++++++++++++--------------------- > drivers/pci/pcie/aer/aerdrv.h | 1 + > 4 files changed, 24 insertions(+), 22 deletions(-) > > -- > 2.7.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html