From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 09 Oct 2013 17:41:35 +0200 (CEST) Received: from mail-qa0-f45.google.com ([209.85.216.45]:62868 "EHLO mail-qa0-f45.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S6839455Ab3JIPl1um5uc (ORCPT ); Wed, 9 Oct 2013 17:41:27 +0200 Received: by mail-qa0-f45.google.com with SMTP id k4so5055893qaq.18 for ; Wed, 09 Oct 2013 08:41:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=OIzuWne1btQIFKe1AaOQsGqgMP43Qniev5+6HLk4I5U=; b=hUvKAdMsQohvjzOwOL4p15MfcazmrTl+J0lRqYmpfYZPKfZmDt+xd8rx6NoSVImiRh 03zdtQPc+/1BmgJlawZiLKAY0WpNJ3XjaLw/jRqgJY9dDipeESEkUvwvtdSzLIhAs3gJ QLM2ZsAqVQJxO9POKosAP66f8cwkXdkcgDQEJHln5GafBvkzRno2JCswmEb7B253KJEG cKTrAqrERKZACrlFl7J9oEsiIsnQhie8VgS4LCsSxsnLMkUTCD1cjmJfSXdzsRB90MgA qEy0I6NBj6p1ZcUPBndIUfpq/GAotw6uMVKFex/Av1EMTJ6ANOknz1MlH6NPW0RlpdtB X1Xw== X-Received: by 10.49.25.102 with SMTP id b6mr3376286qeg.91.1381333281116; Wed, 09 Oct 2013 08:41:21 -0700 (PDT) Received: from htj.dyndns.org (207-38-225-25.c3-0.43d-ubr1.qens-43d.ny.cable.rcn.com. [207.38.225.25]) by mx.google.com with ESMTPSA id a2sm76779565qek.7.1969.12.31.16.00.00 (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 09 Oct 2013 08:41:20 -0700 (PDT) Date: Wed, 9 Oct 2013 11:41:17 -0400 From: Tejun Heo To: Alexander Gordeev Cc: Benjamin Herrenschmidt , Ben Hutchings , linux-kernel@vger.kernel.org, Bjorn Helgaas , Ralf Baechle , Michael Ellerman , Martin Schwidefsky , Ingo Molnar , 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: <20131009154117.GA22495@htj.dyndns.org> 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> <1381009586.645.141.camel@pasglop> <20131006060243.GB28142@dhcp-26-207.brq.redhat.com> <1381040386.645.143.camel@pasglop> <20131006071027.GA29143@dhcp-26-207.brq.redhat.com> <20131007180111.GC2481@htj.dyndns.org> <20131008122215.GA14389@dhcp-26-207.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131008122215.GA14389@dhcp-26-207.brq.redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) 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: 38291 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: tj@kernel.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 Hello, On Tue, Oct 08, 2013 at 02:22:16PM +0200, Alexander Gordeev wrote: > If we talk about pSeries quota, then the current pSeries pci_enable_msix() > implementation is racy internally and could fail if the quota went down > *while* pci_enable_msix() is executing. In this case the loop will have to > exit rather than retry with a lower number (what number?). Ah, okay, so that one is already broken. > In this regard the new scheme does not bring anything new and relies on > the fact this race does not hit and therefore does not worry. > > If we talk about quota as it has to be, then yes - the loop scheme seems > more preferable. > > Overall, looks like we just need to fix the pSeries implementation, > if the guys want it, he-he :) If we can't figure out a better interface for the retry case, I think what can really help is having a simple interface for the simpler cases. > > The problem case is where multiple msi(x) allocation fails completely > > because the global limit went down before inquiry and allocation. In > > the loop based interface, it'd retry with the lower number. > > I am probably missing something here. If the global limit went down before > inquiry then the inquiry will get what is available and try to allocate with > than number. Oh, I should have written between inquiry and allocation. Sorry. Thanks. -- tejun