From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Dreier Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify Date: Tue, 15 Sep 2009 07:57:56 -0700 Message-ID: References: <20090915113434.GF1328@ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20090915113434.GF1328-+ZI9xUNit7I@public.gmane.org> (Pavel Machek's message of "Tue, 15 Sep 2009 13:34:34 +0200") Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Pavel Machek Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, general-ZwoEplunGu1OwGhvXhtEPSCwEArCW2h5@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org List-Id: linux-rdma@vger.kernel.org > I don't remember seeing discussion of this on lkml. Yes it is in > -next... eg http://lkml.org/lkml/2009/7/31/197 and followups, or search for v2 and earlier patches. > Basically it allows app to 'trace itself'? ...with interesting mmap() > interface, exporting int to userspace, hoping it behaves atomically...? Yes, it allows app to trace what the kernel does to memory mappings. I don't believe there's any real issue to atomicity of mmap'ed memory, since userspace really just tests whether read value is == to old read value or not. - R. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754580AbZIOO60 (ORCPT ); Tue, 15 Sep 2009 10:58:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754548AbZIOO6W (ORCPT ); Tue, 15 Sep 2009 10:58:22 -0400 Received: from sj-iport-2.cisco.com ([171.71.176.71]:58521 "EHLO sj-iport-2.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754495AbZIOO6V (ORCPT ); Tue, 15 Sep 2009 10:58:21 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApoEABtIr0qrR7PE/2dsb2JhbADHCohMAY93BYQX X-IronPort-AV: E=Sophos;i="4.44,390,1249257600"; d="scan'208";a="204813764" From: Roland Dreier To: Pavel Machek Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, general@lists.openfabrics.org, akpm@linux-foundation.org, torvalds@linux-foundation.org Subject: Re: [ofa-general] Re: [GIT PULL] please pull ummunotify References: <20090915113434.GF1328@ucw.cz> X-Message-Flag: Warning: May contain useful information Date: Tue, 15 Sep 2009 07:57:56 -0700 In-Reply-To: <20090915113434.GF1328@ucw.cz> (Pavel Machek's message of "Tue, 15 Sep 2009 13:34:34 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.91 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 15 Sep 2009 14:57:57.0275 (UTC) FILETIME=[E92CBEB0:01CA3614] Authentication-Results: sj-dkim-4; header.From=rdreier@cisco.com; dkim=pass ( sig from cisco.com/sjdkim4002 verified; ); Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > I don't remember seeing discussion of this on lkml. Yes it is in > -next... eg http://lkml.org/lkml/2009/7/31/197 and followups, or search for v2 and earlier patches. > Basically it allows app to 'trace itself'? ...with interesting mmap() > interface, exporting int to userspace, hoping it behaves atomically...? Yes, it allows app to trace what the kernel does to memory mappings. I don't believe there's any real issue to atomicity of mmap'ed memory, since userspace really just tests whether read value is == to old read value or not. - R.