From owner-freebsd-current@FreeBSD.ORG Mon Jul 17 17:29:08 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 61D5816A4F2 for ; Mon, 17 Jul 2006 17:29:08 +0000 (UTC) (envelope-from csjp@FreeBSD.org) Received: from ems01.seccuris.com (ems01.seccuris.com [204.112.0.35]) by mx1.FreeBSD.org (Postfix) with SMTP id 9064143D4C for ; Mon, 17 Jul 2006 17:29:07 +0000 (GMT) (envelope-from csjp@FreeBSD.org) Received: (qmail 36107 invoked by uid 86); 17 Jul 2006 18:15:54 -0000 Received: from unknown (HELO ?127.0.0.1?) (204.112.0.40) by ems01.seccuris.com with SMTP; 17 Jul 2006 18:15:54 -0000 Message-ID: <44BBC8F2.3010807@FreeBSD.org> Date: Mon, 17 Jul 2006 12:29:22 -0500 From: "Christian S.J. Peron" User-Agent: Thunderbird 1.5.0.4 (Macintosh/20060530) MIME-Version: 1.0 To: John Baldwin References: <20060712125112.W61255@is.park.rambler.ru> <200607171256.00539.jhb@freebsd.org> In-Reply-To: <200607171256.00539.jhb@freebsd.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Igor Sysoev , freebsd-current@freebsd.org Subject: Re: 2Gb SYSVSHM limitation X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 17 Jul 2006 17:29:08 -0000 John Baldwin wrote: > On Wednesday 12 July 2006 04:58, Igor Sysoev wrote: > >> Hi, >> >> the current kernel limit of SysV memory segment is 2G. >> Today it is too small for amd64 machines. >> >> Year ago Christian S.J. Peron had propsed the patch >> http://people.freebsd.org/~csjp/bigsharedmem.1117028863.diff >> to increase the limit: >> http://freebsd.rambler.ru/bsdmail/freebsd-current_2005/msg05627.html >> >> Are objections against this patch ? >> > > Well, it breaks the ABI of shminfo. :( Changing the ABI of structures shared > with userspace like this requires duplicate syscalls, etc. to not break > existing binaries (such as existing 6.x amd64 binaries). > > I committed this patch, I just have not MFCed it. The ABI breakage is un-clear: I change this structure which should be kernel private, and I dont think we make any guarantees here. We do export this kernel private structure through shmctl(IPC_INFO), however IPC_INFO is not standard. #ifdef _KERNEL /* * System 5 style catch-all structure for shared memory constants that * might be of interest to user programs. Do we really want/need this? */ struct shminfo { int shmmax, /* max shared memory segment size (bytes) */ shmmin, /* min shared memory segment size (bytes) */ shmmni, /* max number of shared memory identifiers */ shmseg, /* max shared memory segments per process */ shmall; /* max amount of shared memory (pages) */ }; I changed these from int to long iirc -- Christian S.J. Peron csjp@FreeBSD.ORG FreeBSD Committer FreeBSD Security Team