From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 7 Jun 2001 19:09:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 7 Jun 2001 19:09:07 -0400 Received: from mail2.aracnet.com ([216.99.193.35]:53767 "EHLO mail2.aracnet.com") by vger.kernel.org with ESMTP id ; Thu, 7 Jun 2001 19:09:03 -0400 Date: Thu, 7 Jun 2001 16:09:01 -0700 (PDT) From: Paul Buder To: Subject: Large ramdisk crashes system Message-ID: 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 I am trying to create a system which boots off of a cd and has no hard disks. So it needs ramdisks. But I haven't had much luck creating large ones. I tried on two different boxes. In both cases the kernel is 2.4.5 with 'Simple RAM-based file system support' turned on. One box is a dual Pentium 750 with a gig of ram in it. I had the kernel 'Default RAM disk size' set to 800000 for this box. I issued the following commands. mkfs /dev/ram0 400000 mount /dev/ram0 /mnt dd if=/dev/zero of=/mnt/junk bs=1024 count=500000 This is fine, dd creates a 400 meg file, reports there isn't enough space and exits. But if I change the first line to mkfs /dev/ram0 500000 I'm essentially crashed. I can ping the box and switch between virtual terminals but that's it. Any program that was running on the other virtual terminals is frozen (as in top, tail, login). The dd is frozen and can't be control-c'd. so I can't do anything other than powercycle. I should have at least 400 megs of ram left for the system so I don't get it. I tried the same thing on a 128 meg box. The results were similar. A 40 meg ram disk worked. A 60 meg ram disk crashed the box. The numbers seem a little odd since in both cases the magic threshold seems to be roughly 40% of ram. I get no messages in the system logfiles nor an oops on the screen. Any ideas?