From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42294) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjOeC-0007Hq-5O for qemu-devel@nongnu.org; Tue, 06 Oct 2015 05:35:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZjOe7-0007fV-2A for qemu-devel@nongnu.org; Tue, 06 Oct 2015 05:35:00 -0400 Received: from e23smtp03.au.ibm.com ([202.81.31.145]:42086) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjOe6-0007ab-Gm for qemu-devel@nongnu.org; Tue, 06 Oct 2015 05:34:55 -0400 Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 6 Oct 2015 19:34:51 +1000 Received: from d23relay09.au.ibm.com (d23relay09.au.ibm.com [9.185.63.181]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 8CF322BB0055 for ; Tue, 6 Oct 2015 20:34:48 +1100 (EST) Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97]) by d23relay09.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t969Ydlq55246886 for ; Tue, 6 Oct 2015 20:34:48 +1100 Received: from d23av03.au.ibm.com (localhost [127.0.0.1]) by d23av03.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t969YFgr019454 for ; Tue, 6 Oct 2015 20:34:15 +1100 Date: Tue, 6 Oct 2015 15:03:54 +0530 From: Bharata B Rao Message-ID: <20151006093354.GA11767@in.ibm.com> References: <1444034124-28747-1-git-send-email-bharata@linux.vnet.ibm.com> <20151005232244-mutt-send-email-mst@redhat.com> <20151006100816.7850ed52@nial.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151006100816.7850ed52@nial.brq.redhat.com> Subject: Re: [Qemu-devel] [RFC v0 0/2] Enforce gaps between DIMMs Reply-To: bharata@linux.vnet.ibm.com List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: david@gibson.dropbear.id.au, qemu-devel@nongnu.org, "Michael S. Tsirkin" On Tue, Oct 06, 2015 at 10:08:16AM +0200, Igor Mammedov wrote: > On Mon, 5 Oct 2015 23:24:33 +0300 > "Michael S. Tsirkin" wrote: > > > On Mon, Oct 05, 2015 at 02:05:22PM +0530, Bharata B Rao wrote: > > > The suggested way to work around the virtio bug reported here > > > > > > http://lists.nongnu.org/archive/html/qemu-devel/2015-08/msg00522.html > > > > > > is to introduce gaps between DIMMs. Igor's patchset changes the pc-dimm > > > auto-address assignment to introduce gaps and ues the same from pc memhp. > > > This patchset does the same for sPAPR PowerPC. > > > > > > Before introducing the gap, ensure that memory hotplug region has enough > > > room for alignment adjustment. We accommodate a max alignment of 256MB for > > > each slot since sPAPR memory hotplug enforces an alignment requirement of > > > 256MB on RAM size, maxmem and NUMA node mem sizes. > > > > > > This applies on David's spapr-next branch + Igor's patchset applied. > > > > > > This has been very lightly tested and intention is to get feedback > > > on the correctness aspect of this. > > > > > > Bharata B Rao (2): > > > spapr: Accommadate alignment gaps in hotplug memory region > > > spapr: Force gaps between DIMM's GPA > > > > PC needs this, PPC needs this ... I don't see why would this not > > apply everywhere. Isn't it time we just converted everyone? > > Drop the gap flag, set it unconditionally for new machine types. > I guess that flag is needed exactly for compatibility with old > machine types which are per board thingy. > > BTW: > does PPC have machine types? I don't see any compatibility > code in this series? For PPC, memory hotplug support starts from machine type pseries-2.5 which is the latest and hence we haven't had a need to be compatible with any other machine type till now. Regards, Bharata.