From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 08 Oct 2013 09:31:12 +0200 (CEST) Received: from mx1.redhat.com ([209.132.183.28]:6553 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6823119Ab3JHHbJ5G-tL (ORCPT ); Tue, 8 Oct 2013 09:31:09 +0200 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r987Utxs022106 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 8 Oct 2013 03:30:55 -0400 Received: from dhcp-26-207.brq.redhat.com (vpn-57-75.rdu2.redhat.com [10.10.57.75]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r987UlPL013127 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Tue, 8 Oct 2013 03:30:49 -0400 Date: Tue, 8 Oct 2013 09:33:02 +0200 From: Alexander Gordeev To: Michael Ellerman Cc: linux-kernel@vger.kernel.org, Bjorn Helgaas , Ralf Baechle , Benjamin Herrenschmidt , Martin Schwidefsky , Ingo Molnar , Tejun Heo , Dan Williams , Andy King , Jon Mason , Matt Porter , linux-pci@vger.kernel.org, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux390@de.ibm.com, linux-s390@vger.kernel.org, x86@kernel.org, linux-ide@vger.kernel.org, iss_storagedev@hp.com, linux-nvme@lists.infradead.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, e1000-devel@lists.sourceforge.net, linux-driver@qlogic.com, Solarflare linux maintainers , "VMware, Inc." , linux-scsi@vger.kernel.org Subject: Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern Message-ID: <20131008073301.GC10669@dhcp-26-207.brq.redhat.com> References: <20131008043330.GF31666@concordia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131008043330.GF31666@concordia> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 38253 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: agordeev@redhat.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Tue, Oct 08, 2013 at 03:33:30PM +1100, Michael Ellerman wrote: > On Wed, Oct 02, 2013 at 12:29:04PM +0200, Alexander Gordeev wrote: > > This technique proved to be confusing and error-prone. Vast share > > of device drivers simply fail to follow the described guidelines. > > To clarify "Vast share of device drivers": > > - 58 drivers call pci_enable_msix() > - 24 try a single allocation and then fallback to MSI/LSI > - 19 use the loop style allocation as above > - 14 try an allocation, and if it fails retry once > - 1 incorrectly continues when pci_enable_msix() returns > 0 > > So 33 drivers (> 50%) successfully make use of the "confusing and > error-prone" return value. Ok, you caught me - 'vast share' is incorrect and is a subject to rewording. But out of 19/58 how many drivers tested fallbacks on the real hardware? IOW, which drivers are affected by the pSeries quota? > And yes, one is buggy, so obviously the interface is too complex. Thanks > drivers/ntb/ntb_hw.c vmxnet3 would be the best example. > cheers -- Regards, Alexander Gordeev agordeev@redhat.com