From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36806) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ynkxt-0003dn-PP for qemu-devel@nongnu.org; Thu, 30 Apr 2015 05:41:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ynkxq-0000Sy-HG for qemu-devel@nongnu.org; Thu, 30 Apr 2015 05:41:05 -0400 Date: Thu, 30 Apr 2015 11:40:41 +0200 From: Thomas Huth Message-ID: <20150430114041.412238a2@thh440s> In-Reply-To: <5541F34D.3070603@suse.de> References: <1430204006-10160-1-git-send-email-nikunj@linux.vnet.ibm.com> <1430204006-10160-2-git-send-email-nikunj@linux.vnet.ibm.com> <20150428133029.3494542e@thh440s> <20150429015638.GC32589@voom.redhat.com> <87sibjxsfo.fsf@abhimanyu.in.ibm.com> <5540975F.3090804@redhat.com> <87pp6nxq0x.fsf@abhimanyu.in.ibm.com> <5540A00D.4080500@redhat.com> <87twvy5it1.fsf@linux.vnet.ibm.com> <5541F34D.3070603@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [REBASE PATCH v5 1/2] machine: add default_ram_size to machine class List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf Cc: Nikunj A Dadhania , aik@ozlabs.ru, armbru@redhat.com, qemu-devel@nongnu.org, qemu-ppc@nongnu.org, marcel.apfelbaum@gmail.com, imammedo@redhat.com, Paolo Bonzini , David Gibson On Thu, 30 Apr 2015 11:18:05 +0200 Alexander Graf wrote: > > > On 30.04.15 06:41, Nikunj A Dadhania wrote: > > > > Hi Paolo, > > > > Paolo Bonzini writes: > >> On 29/04/2015 11:06, Nikunj A Dadhania wrote: > >>>> so David can push both patches. > >>>> > >>>> But isn't 1G a bit too much? At least on x86 you can easily boot with 512M. > >>> > >>> I understood this number as not the _minimum memory_ to boot the > >>> VM. And this will only come in picture when the user has not specified > >>> any memory. > >> > >> This in turn will basically only happen for QEMU developers. So keeping > >> the default on the low side would make sense. > >> > >> On my (4G memory) laptop I might not even be able to boot a PPC64 VM > >> with 1G and TCG, but I can do that nicely with 256M. > > > > That will be fine with me as well, i.e. 256M > > > > David/Alex, Do you have comments on this before we change it? > > I've seen RAM size combinations that seemed to work ok, but then failed > during grub2 execution for example. Please verify with all reasonably > realistically executed distributions that 256MB is enough. Since this default value will likely be there for the next couple of years, it's maybe better to use a slightly higher value than one that is too low - the amount of RAM that a guest requires likely rather increases in the next years instead of going down again. So I think using 512 MB instead is maybe a good compromise? Thomas