From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=55668 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OgaeK-0003TU-TT for qemu-devel@nongnu.org; Wed, 04 Aug 2010 05:52:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OgaeJ-0003tr-LD for qemu-devel@nongnu.org; Wed, 04 Aug 2010 05:52:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50977) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OgaeJ-0003ti-DC for qemu-devel@nongnu.org; Wed, 04 Aug 2010 05:52:35 -0400 Message-ID: <4C593857.9040602@redhat.com> Date: Wed, 04 Aug 2010 12:52:23 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35? References: <4C584B66.5070404@redhat.com> <4C5854F1.3000905@codemonkey.ws> <4C5858B2.9090801@redhat.com> <4C585F5B.5070502@codemonkey.ws> <4C58635B.7020407@redhat.com> <20100803190525.GB16570@redhat.com> <4C586AB9.5040302@codemonkey.ws> <4C586CF9.7030206@redhat.com> <20100803220628.GC28523@amd.home.annexia.org> <4C59009B.1050500@redhat.com> <20100804092428.GD28523@amd.home.annexia.org> In-Reply-To: <20100804092428.GD28523@amd.home.annexia.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Richard W.M. Jones" Cc: kvm@vger.kernel.org, Gleb Natapov , qemu-devel@nongnu.org On 08/04/2010 12:24 PM, Richard W.M. Jones wrote: >>> >>> Just like the initrd? >> There isn't enough address space for a 100MB initrd in ROM. > Because of limits of the original PC, sure, where you had to fit > everything in 0xa0000-0xfffff or whatever it was. > > But this isn't a real PC. > > You can map the read-only memory anywhere you want. I wasn't talking about the 1MB limit, rather the 4GB limit. Of that, 3-3.5GB are reserved for RAM, 0.5-1GB for PCI. Putting large amounts of ROM in that space will cost us PCI space. 100 MB initrds are a bad idea for multiple reasons. Demand paging is there for a reason. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.