Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754406Ab0BKMqv (ORCPT ); Thu, 11 Feb 2010 07:46:51 -0500 Received: from fxip-0047f.externet.hu ([88.209.222.127]:56839 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752725Ab0BKMqu (ORCPT ); Thu, 11 Feb 2010 07:46:50 -0500 To: Tejun Heo CC: miklos@szeredi.hu, mszeredi@suse.cz, linux-kernel@vger.kernel.org, fuse-devel@lists.sourceforge.net, polynomial-c@gentoo.org, akpm@linux-foundation.org In-reply-to: <4B73FCF2.3020108@kernel.org> (message from Tejun Heo on Thu, 11 Feb 2010 21:49:54 +0900) Subject: Re: [fuse-devel] [PATCH] FUSE/CUSE: implement direct mmap support References: <4B70FBE4.7050700@kernel.org> <4B7296DF.207@kernel.org> <4B729F07.8020704@kernel.org> <4B72A802.6040009@kernel.org> <4B7344A4.1030607@kernel.org> <4B73F006.7090706@kernel.org> <4B73FCF2.3020108@kernel.org> Message-Id: From: Miklos Szeredi Date: Thu, 11 Feb 2010 13:46:35 +0100 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1282 Lines: 31 On Thu, 11 Feb 2010, Tejun Heo wrote: > Hello, Miklos. > > On 02/11/2010 09:25 PM, Miklos Szeredi wrote: > >> If the server wants the two regions to be separate, it can map it to > >> say 5-11 and returnt he offset of 5. If it wants them to be shared, > >> it will have to mmap 1-2 and 6-7 and return offset of 1. > > > > What if region 6-7 is already occupied (e.g. because a separate region > > was put there)? > > Allocating and managing the address space ranges are the server's > responsibility. If it expects the region to grow, it shouldn't > colocate those regions. The kernel is just giving the server an > address space to manage and letting it redirect mmaps to arbitrary > (sans the SHMLBA alignment restriction) part of it. The rest is upto > the server. The problem with that is you simply can't determine in advance where the region will grow. Okay, you can leave space according to the size of the file, but the size of the file can grow too. *This* is the complexity that I want to get rid of. Thanks, Miklos -- 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/