Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756301Ab3EOB6I (ORCPT ); Tue, 14 May 2013 21:58:08 -0400 Received: from mail-pb0-f43.google.com ([209.85.160.43]:42545 "EHLO mail-pb0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751722Ab3EOB6G (ORCPT ); Tue, 14 May 2013 21:58:06 -0400 Message-ID: <5192EBAB.7030203@gmail.com> Date: Tue, 14 May 2013 18:58:03 -0700 From: Alexander Duyck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4 MIME-Version: 1.0 To: Or Gerlitz CC: Alexander Duyck , bhelgaas@google.com, yinghai@kernel.org, guz.fnst@cn.fujitsu.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, "Michael S. Tsirkin" Subject: Re: [PATCH] pci: Avoid reentrant calls to work_on_cpu References: <20130514221748.6180.30597.stgit@ahduyck-cp1.jf.intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2842 Lines: 73 On 05/14/2013 05:32 PM, Or Gerlitz wrote: > On Tue, May 14, 2013 at 6:26 PM, Alexander Duyck > wrote: >> >> This change is meant to fix a deadlock seen when pci_enable_sriov was >> called from within a driver's probe routine. The issue was that >> work_on_cpu calls flush_work which attempts to flush a work queue for a >> cpu that we are currently working in. In order to avoid the reentrant >> path we just skip the call to work_on_cpu in the case that the device >> node matches our current node. >> >> Reported-by: Yinghai Lu >> Signed-off-by: Alexander Duyck >> --- >> >> This patch is meant to address the issue pointed out in an earlier patch >> sent by Yinghai Lu titled: >> [PATCH 6/7] PCI: Make sure VF's driver get attached after PF's >> >> drivers/pci/pci-driver.c | 14 +++++++++----- >> 1 files changed, 9 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c >> index 79277fb..caeb1c0 100644 >> --- a/drivers/pci/pci-driver.c >> +++ b/drivers/pci/pci-driver.c >> @@ -277,12 +277,16 @@ static int pci_call_probe(struct pci_driver *drv, >> struct pci_dev *dev, >> int error, node; >> struct drv_dev_and_id ddi = { drv, dev, id }; >> >> - /* Execute driver initialization on node where the device's >> - bus is attached to. This way the driver likely allocates >> - its local memory on the right node without any need to >> - change it. */ >> + /* >> + * Execute driver initialization on the node where the device's >> + * bus is attached. This way the driver likely allocates >> + * its local memory on the right node without any need to >> + * change it. If the node is the current node just call >> + * local_pci_probe and avoid the possibility of reentrant >> + * calls to work_on_cpu. >> + */ >> node = dev_to_node(&dev->dev); >> - if (node >= 0) { >> + if ((node >= 0) && (node != numa_node_id())) { >> int cpu; >> >> get_online_cpus(); > > > Alex, FWIW a similar patch was posted by Michael during the last rc > cycles of 3.9 see > http://marc.info/?l=linux-netdev&m=136569426119644&w=2 Did his patch ever get applied anywhere? I don't see it in any of the trees. The advantage this approach has over the one in the similar patch is that this covers a broader set of CPUs since anything on the same node is local versus just the first CPU in a given NUMA node. Thanks, Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/