From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mario Smarduch Subject: Re: maybe a virtio-balloon-device issue ? Date: Mon, 09 Feb 2015 09:38:39 -0800 Message-ID: <54D8F09F.1010001@samsung.com> References: <54D41681.7080401@samsung.com> <54D4E459.9040007@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: "kvm@vger.kernel.org" , "kvmarm@lists.cs.columbia.edu" , "christoffer.dall@linaro.org" , Marc Zyngier , Gleb Natapov , Peter Maydell To: Paolo Bonzini Return-path: Received: from mailout1.w2.samsung.com ([211.189.100.11]:42367 "EHLO usmailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755875AbbBIRim (ORCPT ); Mon, 9 Feb 2015 12:38:42 -0500 Received: from uscpsbgex1.samsung.com (u122.gpu85.samsung.co.kr [203.254.195.122]) by mailout1.w2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NJI00AC7MCGOT00@mailout1.w2.samsung.com> for kvm@vger.kernel.org; Mon, 09 Feb 2015 12:38:40 -0500 (EST) In-reply-to: <54D4E459.9040007@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Thanks for the pointer I'll try it out. - mario On 02/06/2015 07:57 AM, Paolo Bonzini wrote: > > > On 06/02/2015 02:18, Mario Smarduch wrote: >> Hi, >> >> I'm looking into qemu/balloon driver VM overcommit. I noticed >> virtio-balloon driver will take any setting from virtio-balloon-device >> to the point Guest dies. >> >> For a 1G guest >> $ sudo echo balloon 100 | socat - tcp4-connect:127.0.0.1:4444 >> >> you get (same with libvirt setmem) >> >> root@localhost:~# free >> -bash: fork: Cannot allocate memory >> root@localhost:~# ps >> -bash: fork: Cannot allocate memory >> >> $ sudo info balloon | socat ... - confirms setting >> >> The balloon driver has been there for a while, not sure what I'm missing? >> >> virtio-balloon-device provide free memory, i.e., - externally accessible >> to host. But this appears more like a hint for an inflate request, snmp >> mibs >> provide more detailed resource info then that. >> >> I'm wondering if the driver should not have some heuristic >> check for an inflate request so it doesn't over inflate? Similar to >> kernel overcommit. > > See this patch: > > commit 5a10b7dbf904bfe01bb9fcc6298f7df09eed77d5 > Author: Raushaniya Maksudova > Date: Mon Nov 10 09:36:29 2014 +1030 > > virtio_balloon: free some memory from balloon on OOM > > Looks like the QEMU part was never posted though. > > Paolo >