From owner-freebsd-ia64 Thu Feb 6 17:33:57 2003 Delivered-To: freebsd-ia64@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6A94437B401 for ; Thu, 6 Feb 2003 17:33:56 -0800 (PST) Received: from ns1.xcllnt.net (209-128-86-226.bayarea.net [209.128.86.226]) by mx1.FreeBSD.org (Postfix) with ESMTP id B18CA43FA3 for ; Thu, 6 Feb 2003 17:33:55 -0800 (PST) (envelope-from marcel@xcllnt.net) Received: from athlon.pn.xcllnt.net (athlon.pn.xcllnt.net [192.168.4.3]) by ns1.xcllnt.net (8.12.6/8.12.6) with ESMTP id h171XtL4023572; Thu, 6 Feb 2003 17:33:55 -0800 (PST) (envelope-from marcel@piii.pn.xcllnt.net) Received: from athlon.pn.xcllnt.net (localhost [127.0.0.1]) by athlon.pn.xcllnt.net (8.12.6/8.12.6) with ESMTP id h171Xthm001061; Thu, 6 Feb 2003 17:33:55 -0800 (PST) (envelope-from marcel@athlon.pn.xcllnt.net) Received: (from marcel@localhost) by athlon.pn.xcllnt.net (8.12.6/8.12.6/Submit) id h171Xtju001060; Thu, 6 Feb 2003 17:33:55 -0800 (PST) (envelope-from marcel) Date: Thu, 6 Feb 2003 17:33:55 -0800 From: Marcel Moolenaar To: Arun Sharma Cc: freebsd-ia64@FreeBSD.ORG Subject: Re: msgbuf size Message-ID: <20030207013355.GB1030@athlon.pn.xcllnt.net> References: <200302070124.h171OFr08115@unix-os.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200302070124.h171OFr08115@unix-os.sc.intel.com> User-Agent: Mutt/1.5.3i Sender: owner-freebsd-ia64@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Thu, Feb 06, 2003 at 05:24:15PM -0800, Arun Sharma wrote: > > When I configure my box with a large msgbuf, so that I can see verbose > boot messages, I get: > > WARNING: 106496 bytes not available for msgbuf in last cluster (8192 used) > > This seems to be related to this comment in machdep.c: > > /* > * Initialize error message buffer (at end of core). > */ > > Does it have to be at the end of core ? No. It's one of the many things that needs to be revisited. It's legacy behaviour... > Why not use pmap_steal_memory to get hold of memory ? Precisely :-) AFAICT we deliberately avoid clearing the msgbuf so that we don't trash it across a reboot. For this to work we have to use the same memory address for the msgbuf. My personal stance on this is that not clobbering the msgbuf across a reboot just adds to the junk you have to scroll passed to get to the info you want with dmesg(8) and also that there's no point trying to hard, because EFI adds a level of randomness to this. So, from my point of view grabbing the first available memory and clearing it works for me. YMMV... -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-ia64" in the body of the message