Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750703AbWJPOLO (ORCPT ); Mon, 16 Oct 2006 10:11:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750709AbWJPOLO (ORCPT ); Mon, 16 Oct 2006 10:11:14 -0400 Received: from dhost002-49.dex002.intermedia.net ([64.78.21.145]:35899 "EHLO dhost002-49.dex002.intermedia.net") by vger.kernel.org with ESMTP id S1750703AbWJPOLN (ORCPT ); Mon, 16 Oct 2006 10:11:13 -0400 Message-ID: <453392CD.1050504@qlusters.com> Date: Mon, 16 Oct 2006 16:10:21 +0200 From: Constantine Gavrilov Reply-To: Constantine Gavrilov Organization: Qlusters User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.7.13) Gecko/20060501 Fedora/1.7.13-1.1.fc5 X-Accept-Language: ru, en-us, en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: Would SSI clustering extensions be of interest to kernelcommunity? References: <45337FE3.8020201@qlusters.com> <1161006841.24237.33.camel@localhost.localdomain> In-Reply-To: <1161006841.24237.33.camel@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 16 Oct 2006 14:11:11.0851 (UTC) FILETIME=[EF1343B0:01C6F12C] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2055 Lines: 60 Alan Cox wrote: >Ar Llu, 2006-10-16 am 14:49 +0200, ysgrifennodd Constantine Gavrilov: > > >>2) Are kernel maintainers interested in clustering extensions to Linux >>kernel? Do they see any value in them? (Our code does not require kernel >>changes, but we are willing to submit it for inclusion if there is >>interest.) >> >> > >If they are doing SSI well and do not need core kernel changes then yes >they sound very interesting to me. Historically the big concern has >always been that things like this muck up the kernel core which affects >the other 99.99999% of users who don't want SSI clustering. > >Alan > > > > SSI intrudes kernel in two places: a) IO system calls, b ) page fault code for shared memory pages. a) IO system calls are "packed" and forwarded to the "home" node, where original syscall code is executed. b) A hook is inserted into page fault code that brings shared memory pages from other nodes when necessary. Apart from these two hooks, SSI code is a "standalone" kernel API add-on ("add", not "change"). Currently, we can do both "intrusions" from the kernel module. I assume that if we submit code, you will require a kernel patch that explicitly calls our hooks. Also, continuous SSI in-kernel support may require SSI changes in the following cases: a) new fields in task struct that reflect process state (may affect task migration), b) changes in the page fault mechanism (may effect SSI shared memory code that brings and invalidates pages), c) addition of new system calls (may require implementation of SSI suspport for them). -- ---------------------------------------- Constantine Gavrilov Kernel Developer Qlusters Software Ltd 1 Azrieli Center, Tel-Aviv Phone: +972-3-6081977 Fax: +972-3-6081841 ---------------------------------------- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/