From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55105) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRDHh-00077H-G9 for qemu-devel@nongnu.org; Thu, 04 Feb 2016 01:20:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aRDHe-0001O5-AO for qemu-devel@nongnu.org; Thu, 04 Feb 2016 01:20:53 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40974) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRDHe-0001O1-2d for qemu-devel@nongnu.org; Thu, 04 Feb 2016 01:20:50 -0500 From: Markus Armbruster References: <1453963872-13549-1-git-send-email-vsementsov@virtuozzo.com> <1453963872-13549-4-git-send-email-vsementsov@virtuozzo.com> <56B12A05.4060305@redhat.com> <87vb65n6le.fsf@blackfin.pond.sub.org> <56B23707.3030800@virtuozzo.com> Date: Thu, 04 Feb 2016 07:20:45 +0100 In-Reply-To: <56B23707.3030800@virtuozzo.com> (Vladimir Sementsov-Ogievskiy's message of "Wed, 3 Feb 2016 20:21:11 +0300") Message-ID: <87mvrhf136.fsf@blackfin.pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Qemu-devel] [PATCH 3/3] balloon: don't use NVDIMM for ballooning List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladimir Sementsov-Ogievskiy Cc: Xiao Guangrong , "Michael S. Tsirkin" , qemu-devel@nongnu.org, Stefan Hajnoczi , "Denis V. Lunev" , Igor Mammedov Vladimir Sementsov-Ogievskiy writes: > On 03.02.2016 18:42, Markus Armbruster wrote: >> Eric Blake writes: >> >>> On 01/27/2016 11:51 PM, Vladimir Sementsov-Ogievskiy wrote: >>>> NVDIMM for now is planned to use as a backing store for DAX filesystem >>>> in the guest and thus this memory is excluded from guest memory >>>> management and LRUs. >>>> >>>> In this case libvirt running QEMU along with configured balloon almost >>>> immediately inflates balloon and effectively kill the guest as >>>> qemu counts nvdimm as part of the ram. >>>> >>>> Counting dimm devices as part of the ram for ballooning was started from >>>> commit 463756d03: >>>> virtio-balloon: Fix balloon not working correctly when hotplug memory >>>> >>>> Signed-off-by: Vladimir Sementsov-Ogievskiy >>>> Signed-off-by: Denis V. Lunev >>>> CC: Stefan Hajnoczi >>>> CC: Xiao Guangrong >>>> CC: "Michael S. Tsirkin" >>>> CC: Igor Mammedov >>>> CC: Eric Blake >>>> CC: Markus Armbruster >>>> --- >>>> @@ -308,7 +309,9 @@ static ram_addr_t get_current_ram_size(void) >>>> if (value) { >>>> switch (value->type) { >>>> case MEMORY_DEVICE_INFO_KIND_DIMM: >>>> - size += value->u.dimm->size; >>>> + if (strcmp(value->u.dimm->type, TYPE_NVDIMM)) { >>> If you fix 2/3 to use a QAPI enum, then this will be an integer compare >>> instead of a strcmp(). >> Another option is to add a flag to the subtypes of TYPE_PC_DIMM, set it >> for the subtypes that should be counted here, and accumulate the sizes >> of devices where the flag is set. Requires iterating directly over the >> devices here (like qmp_pc_dimm_device_list() does under the hood) rather >> than the MemoryDeviceInfoList returned by qmp_pc_dimm_device_list(), > It was my first approach but it was rejected) > > As another option I can make a function iterating over the devices and > return list of them, and then use it instead of > qmp_pc_dimm_device_list.. Then, I'll have pointers to devices and can > use object_dynamic_cast. I fail to see how splitting a tree walk doing stuff into a tree walk creating a list and a list walk doing stuff makes things better :) Anyway, you guys figure it out. The only part where I get involved is QAPI design.