From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754912AbYHTOpk (ORCPT ); Wed, 20 Aug 2008 10:45:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751772AbYHTOpb (ORCPT ); Wed, 20 Aug 2008 10:45:31 -0400 Received: from mx1.redhat.com ([66.187.233.31]:58377 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751764AbYHTOpb (ORCPT ); Wed, 20 Aug 2008 10:45:31 -0400 Subject: Re: distributed shared memory / mmap From: Steven Whitehouse To: Martin Uecker Cc: linux-kernel@vger.kernel.org In-Reply-To: <1219238336.8097.29.camel@localhost> References: <1219238336.8097.29.camel@localhost> Content-Type: text/plain Organization: Red Hat (UK) Ltd (Registered in England and Wales, No. 3798903) Registered office: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 ITE Date: Wed, 20 Aug 2008 15:43:24 +0100 Message-Id: <1219243404.20622.156.camel@quoit> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-2.fc6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wed, 2008-08-20 at 15:18 +0200, Martin Uecker wrote: > > Hi! > > Is there any easy way to get shared memory between to > processes on different machines? It seems possible using mmap > on a file system like GFS on top of a distributed block device. > > > Sincerly, > Martin Uecker > Yes, you can do it using GFS/GFS2 and it should work. On the other hand, don't do it. Its probably not what you want and unlikely to give you good performance since the locking is "per inode" and thus you'll generate a lot of cache flushing if there is any appreciable amount of writing to the shared region. If you have a read mostly (or only) workload, then it will work much better. There are often better solutions though, depending on the application in question, Steve.