From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932094AbWJPOSI (ORCPT ); Mon, 16 Oct 2006 10:18:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932095AbWJPOSI (ORCPT ); Mon, 16 Oct 2006 10:18:08 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:19104 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S932094AbWJPOSF (ORCPT ); Mon, 16 Oct 2006 10:18:05 -0400 Subject: Re: Would SSI clustering extensions be of interest to kernelcommunity? From: Alan Cox To: Constantine Gavrilov Cc: linux-kernel@vger.kernel.org In-Reply-To: <45339234.4050400@qlusters.com> References: <45337FE3.8020201@qlusters.com> <1161006841.24237.33.camel@localhost.localdomain> <45339234.4050400@qlusters.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Mon, 16 Oct 2006 15:44:50 +0100 Message-Id: <1161009890.24237.36.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ar Llu, 2006-10-16 am 16:07 +0200, ysgrifennodd Constantine Gavrilov: > 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. Yep. Thats probably the most critical single thing to review. > > 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). SSI changes triggered from core changes are fairly expected I think because you need to serialize new objects.