Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965661AbXFFX3X (ORCPT ); Wed, 6 Jun 2007 19:29:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935394AbXFFX3Q (ORCPT ); Wed, 6 Jun 2007 19:29:16 -0400 Received: from x35.xmailserver.org ([64.71.152.41]:4989 "EHLO x35.xmailserver.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751472AbXFFX3P (ORCPT ); Wed, 6 Jun 2007 19:29:15 -0400 X-AuthUser: davidel@xmailserver.org Date: Wed, 6 Jun 2007 16:29:13 -0700 (PDT) From: Davide Libenzi X-X-Sender: davide@alien.or.mcafeemobile.com To: Alan Cox cc: Linux Kernel Mailing List , Linus Torvalds , Andrew Morton , Ulrich Drepper , Ingo Molnar , Eric Dumazet Subject: Re: [patch 7/8] fdmap v2 - implement sys_socket2 In-Reply-To: <20070607001932.35c9591c@the-village.bc.nu> Message-ID: References: <20070606235906.72439d16@the-village.bc.nu> <20070607001932.35c9591c@the-village.bc.nu> X-GPG-FINGRPRINT: CFAE 5BEE FD36 F65E E640 56FE 0974 BF23 270F 474E X-GPG-PUBLIC_KEY: http://www.xmailserver.org/davidel.asc MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1291 Lines: 33 On Thu, 7 Jun 2007, Alan Cox wrote: > > > prctl(PR_SPARSEFD, 1); > > > > > > to turn on sparse fd allocation for a process ? > > > > There was a little discussion where I tried to whisper something similar, > > but Linus and Uli shot me :) - with good reasons IMO. > > You may link to runtimes that are not non-sequentialfd aware, and will > > break them. > > Linking to the correct version of a libary and getting the library > versioning right is not rocket science and isn't a sane excuse. Its no > different to the stdio to large fd migration issues with many Unixen and > they all coped just fine. I don't think it's a matter of versioning. Many userspace libraries expects their fds to be compact (for many reasons - they use select, they use them to index 0-based arrays, etc...), and if the kernel suddendly starts returning values in the 1<<28 up arena, they sure won't be happy. So I believe that the correct way is that the caller specifically selects the feature, leaving the legacy fd allocation as default. - Davide - 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/