From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e8.ny.us.ibm.com (e8.ny.us.ibm.com [32.97.182.138]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e8.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id B3669DDEF9 for ; Tue, 14 Oct 2008 23:29:25 +1100 (EST) Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e8.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id m9ECQMdQ018550 for ; Tue, 14 Oct 2008 08:26:22 -0400 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id m9ECTJel222468 for ; Tue, 14 Oct 2008 08:29:19 -0400 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m9ECTJEn015829 for ; Tue, 14 Oct 2008 08:29:19 -0400 Subject: Re: [PATCH]IB/ehca:reject dynamic memory add/remove From: Dave Hansen To: Stefan Roscher In-Reply-To: <200810141423.48111.stefan.roscher@vnet.de.ibm.com> References: <200810131310.34413.ossrosch@linux.vnet.ibm.com> <1223917766.29877.17.camel@nimitz> <200810141423.48111.stefan.roscher@vnet.de.ibm.com> Content-Type: text/plain Date: Tue, 14 Oct 2008 05:29:13 -0700 Message-Id: <1223987353.29877.40.camel@nimitz> Mime-Version: 1.0 Cc: LKML , Stefan Roscher , LinuxPPC-Dev , general@lists.openfabrics.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2008-10-14 at 14:23 +0200, Stefan Roscher wrote: > On Monday 13 October 2008 07:09:26 pm Dave Hansen wrote: > > On Mon, 2008-10-13 at 13:10 +0200, Stefan Roscher wrote: > > > Since the ehca device driver does not support dynamic memory add and remove > > > operations, the driver must explicitly reject such requests in order to prevent > > > unpredictable behaviors related to memory regions already occupied and being > > > used by InfiniBand applications. > > > The solution is to add a memory notifier to the ehca device driver and if a request > > > for dynamic memory add or remove comes in, ehca will always reject it. > > > > Why doesn't the driver support it? > > > > This seems like an awfully extreme action to take. Do you have plans to > > support this in the driver soon? > > > There is currently a slight incompatibility how openfabrics uses MRs > and how System p does DMEM add/remove, which basically disables this > support. > If you want to talk to the firmware developpers, I can give you the right contacts. I wish I knew what an 'MR' is. :( Could you be a bit more specific so we can get a better changelog? Perhaps if we understand the situation better, we can come up with a better solution. Does this have anything in common with the problems with 16GB pages? -- Dave