From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ale.deltatee.com (ale.deltatee.com. [207.54.116.67]) by gmr-mx.google.com with ESMTPS id c11si2499862pfc.2.2016.06.15.16.11.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 15 Jun 2016 16:11:46 -0700 (PDT) References: <1466026416.16234.262.camel@intel.com> <5761D4C5.8090208@deltatee.com> <1466029459.16234.263.camel@intel.com> From: Logan Gunthorpe Message-ID: <5761E0A0.4060505@deltatee.com> Date: Wed, 15 Jun 2016 17:11:28 -0600 MIME-Version: 1.0 In-Reply-To: <1466029459.16234.263.camel@intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [PATCH v3 10/10] ntb_perf: clear link_is_up flag when the link goes down. To: "Jiang, Dave" , "Allen.Hubbe@emc.com" , "jdmason@kudzu.us" Cc: "linux-kernel@vger.kernel.org" , "shuahkh@osg.samsung.com" , "sudipm.mukherjee@gmail.com" , "linux-kselftest@vger.kernel.org" , "arnd@arndb.de" , "linux-ntb@googlegroups.com" List-ID: Hey, On 15/06/16 04:24 PM, Jiang, Dave wrote: > On Wed, 2016-06-15 at 16:20 -0600, Logan Gunthorpe wrote: >> Hey, >> >> Actually, I have to retract this patch. After some more thorough >> testing >> I'm finding an issue: >> >> When you remove and re-install the ntb_perf module very quickly, >> ntb_perf will occasionally miss the link up event. This is because >> the >> link_cleanup work gets delayed long enough that it gets scheduled >> after >> the link up event gets sent. It then cancels the link work that >> should >> have occurred. Without this patch, it never happens because >> link_is_up >> never returns to false. >> >> I think the correct solution is to just remove the link_cleanup work >> and >> do those actions immediately on receipt of the event. If there's >> agreement on this I can re-spin it again. > > I'm ok with that. This is not an issue with ntb_transport? Looks like I can get something similar to happen in ntb_transport. However, it's much rarer and takes significantly more tries to get it to occur. It does appear to correctly set its link_is_up to false when the link goes down. I'm not sure I'm quite clear on the flow in ntb_transport and don't have time right now to study it so I'll have to let that be someone else's (fairly minor) issue. Logan