From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt Subject: Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern Date: Sun, 06 Oct 2013 08:46:26 +1100 Message-ID: <1381009586.645.141.camel@pasglop> References: <1380840585.3419.50.camel@bwh-desktop.uk.level5networks.com> <20131004082920.GA4536@dhcp-26-207.brq.redhat.com> <1380922156.3214.49.camel@bwh-desktop.uk.level5networks.com> <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: Alexander Gordeev Cc: Ben Hutchings , linux-kernel@vger.kernel.org, Bjorn Helgaas , Ralf Baechle , Michael Ellerman , 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@qlo List-Id: linux-ide@vger.kernel.org On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote: > So my point is - drivers should first obtain a number of MSIs they *can* > get, then *derive* a number of MSIs the device is fine with and only then > request that number. Not terribly different from memory or any other type > of resource allocation ;) What if the limit is for a group of devices ? Your interface is racy in that case, another driver could have eaten into the limit in between the calls. Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sat, 05 Oct 2013 23:47:28 +0200 (CEST) Received: from gate.crashing.org ([63.228.1.57]:42542 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6868704Ab3JEVrYyRMvM (ORCPT ); Sat, 5 Oct 2013 23:47:24 +0200 Received: from [127.0.0.1] (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.13.8) with ESMTP id r95LkREF008051; Sat, 5 Oct 2013 16:46:29 -0500 Message-ID: <1381009586.645.141.camel@pasglop> Subject: Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern From: Benjamin Herrenschmidt To: Alexander Gordeev Cc: Ben Hutchings , linux-kernel@vger.kernel.org, Bjorn Helgaas , Ralf Baechle , Michael Ellerman , 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 Date: Sun, 06 Oct 2013 08:46:26 +1100 In-Reply-To: <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> References: <1380840585.3419.50.camel@bwh-desktop.uk.level5networks.com> <20131004082920.GA4536@dhcp-26-207.brq.redhat.com> <1380922156.3214.49.camel@bwh-desktop.uk.level5networks.com> <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit 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: 38207 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: benh@kernel.crashing.org 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 Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote: > So my point is - drivers should first obtain a number of MSIs they *can* > get, then *derive* a number of MSIs the device is fine with and only then > request that number. Not terribly different from memory or any other type > of resource allocation ;) What if the limit is for a group of devices ? Your interface is racy in that case, another driver could have eaten into the limit in between the calls. Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 From: benh@kernel.crashing.org (Benjamin Herrenschmidt) Date: Sun, 06 Oct 2013 08:46:26 +1100 Subject: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern In-Reply-To: <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> References: <1380840585.3419.50.camel@bwh-desktop.uk.level5networks.com> <20131004082920.GA4536@dhcp-26-207.brq.redhat.com> <1380922156.3214.49.camel@bwh-desktop.uk.level5networks.com> <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> Message-ID: <1381009586.645.141.camel@pasglop> On Sat, 2013-10-05@16:20 +0200, Alexander Gordeev wrote: > So my point is - drivers should first obtain a number of MSIs they *can* > get, then *derive* a number of MSIs the device is fine with and only then > request that number. Not terribly different from memory or any other type > of resource allocation ;) What if the limit is for a group of devices ? Your interface is racy in that case, another driver could have eaten into the limit in between the calls. Ben. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 8AF892C00A7 for ; Sun, 6 Oct 2013 08:47:59 +1100 (EST) Message-ID: <1381009586.645.141.camel@pasglop> Subject: Re: [PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern From: Benjamin Herrenschmidt To: Alexander Gordeev Date: Sun, 06 Oct 2013 08:46:26 +1100 In-Reply-To: <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> References: <1380840585.3419.50.camel@bwh-desktop.uk.level5networks.com> <20131004082920.GA4536@dhcp-26-207.brq.redhat.com> <1380922156.3214.49.camel@bwh-desktop.uk.level5networks.com> <20131005142054.GA11270@dhcp-26-207.brq.redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: linux-mips@linux-mips.org, "VMware, Inc." , linux-pci@vger.kernel.org, linux-nvme@lists.infradead.org, linux-ide@vger.kernel.org, linux-s390@vger.kernel.org, Andy King , linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org, x86@kernel.org, Ben Hutchings , Ingo Molnar , iss_storagedev@hp.com, linux-driver@qlogic.com, Martin Schwidefsky , Bjorn Helgaas , Dan Williams , Jon Mason , Solarflare linux maintainers , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Ralf Baechle , e1000-devel@lists.sourceforge.net, Tejun Heo , linux390@de.ibm.com, linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, 2013-10-05 at 16:20 +0200, Alexander Gordeev wrote: > So my point is - drivers should first obtain a number of MSIs they *can* > get, then *derive* a number of MSIs the device is fine with and only then > request that number. Not terribly different from memory or any other type > of resource allocation ;) What if the limit is for a group of devices ? Your interface is racy in that case, another driver could have eaten into the limit in between the calls. Ben.