From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: megasas stops I/O when running kernel as dom0 under xen4.1/4.2 Date: Fri, 19 Aug 2011 13:28:30 +0100 Message-ID: <4E4E56EE.2070801@citrix.com> References: <4E43E04B.8010401@leuphana.de> <20110811225119.GA3557@dumpdata.com> <4E44EE51.70802@leuphana.de> <201108151149.44053.simon.rowe@eu.citrix.com> <4E4916A3.9070106@leuphana.de> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4E4916A3.9070106@leuphana.de> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Andreas Olsowski Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On 15/08/11 13:52, Andreas Olsowski wrote: > On 08/15/2011 12:49 PM, Simon Rowe wrote: >> I've found adding >> >> options megaraid_sas poll_mode_io=1 >> >> makes both of the systems we're seeing this on stable. > ive been told to try that one and it works for me too (been running test > io for roughly 5 minutes now). > > driver version > megasas: 00.00.05.30 Tue. Jan. 4 17:00:00 PDT 2011 Hello - I am now debugging. It seems that the megaraid_sas driver will try and use either MSI-X or legacy PCI interrupts mode, but will never try to use MSI. The box we can reproduce the problem on has MSI support but not MSI-X support. As an experiment, I put a single call to pci_enable_msi() in the megasas_probe_one() function, immediately after pci_set_master(). I now cannot reproduce the problem. Do any of the boxes you have which reproduce the problem set up MSI-X interrupts for the megasas driver, or are they all using legacy PCI interrupts? (I am also emailing an LSI contact asking why they do not use MSI interrupts) ~Andrew -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com