From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750794AbWGLTGl (ORCPT ); Wed, 12 Jul 2006 15:06:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750796AbWGLTGl (ORCPT ); Wed, 12 Jul 2006 15:06:41 -0400 Received: from sj-iport-6.cisco.com ([171.71.176.117]:58811 "EHLO sj-iport-6.cisco.com") by vger.kernel.org with ESMTP id S1750794AbWGLTGk (ORCPT ); Wed, 12 Jul 2006 15:06:40 -0400 To: Ingo Molnar Cc: Zach Brown , Linux Kernel Mailing List , openib-general@openib.org, Arjan van de Ven Subject: Re: [openib-general] ipoib lockdep warning X-Message-Flag: Warning: May contain useful information References: <44B405C8.4040706@oracle.com> <44B433CE.1030103@oracle.com> <20060712093820.GA9218@elte.hu> From: Roland Dreier Date: Wed, 12 Jul 2006 12:06:37 -0700 Message-ID: User-Agent: Gnus/5.1007 (Gnus v5.10.7) XEmacs/21.4.18 (linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 12 Jul 2006 19:06:39.0512 (UTC) FILETIME=[4DEDA980:01C6A5E6] Authentication-Results: sj-dkim-3.cisco.com; header.From=rdreier@cisco.com; dkim=pass ( sig from cisco.com verified; ); Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > i agree that the IDR subsystem should be irq-safe if GFP_ATOMIC is > passed in. So the _irqsave()/_irqrestore() fix should be done. OK, I will send the idr change to Andrew. > But i also think that you should avoid using GFP_ATOMIC for any sort of > reliable IO path and push as much work into process context as possible. > Is it acceptable for your infiniband IO model to fail with -ENOMEM if > GFP_ATOMIC happens to fail, and is the IO retried transparently? Yes, I think it's OK. This idr use is in an inherently unreliable path. With that said, as Michael pointed out, we can change things to use GFP_ATOMIC less. Thanks, Roland