From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50870) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ejOVD-0002dB-K0 for qemu-devel@nongnu.org; Wed, 07 Feb 2018 07:07:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ejOV3-0004tA-Tq for qemu-devel@nongnu.org; Wed, 07 Feb 2018 07:07:03 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:56294 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ejOV3-0004sj-PC for qemu-devel@nongnu.org; Wed, 07 Feb 2018 07:06:53 -0500 Date: Wed, 7 Feb 2018 13:06:35 +0100 From: Igor Mammedov Message-ID: <20180207130635.4033f8b8@redhat.com> In-Reply-To: References: <1517842735-9011-1-git-send-email-jianfeng.tan@intel.com> <1b6a1999-95bb-5eac-70e1-39e6ba5b22fc@redhat.com> <6716e932-9ce5-3d97-41cb-f33ea94ad4ce@intel.com> <502bbdba-0c35-e35a-6600-dfca739d0ea3@redhat.com> <20180205181521.47232aa4@redhat.com> <5155622d-cc49-d24c-7a7d-24ebb9ca2331@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [RFC] exec: eliminate ram naming issue as migration List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Tan, Jianfeng" Cc: Paolo Bonzini , "qemu-devel@nongnu.org" , Jason Wang , Maxime Coquelin , "Michael S . Tsirkin" On Wed, 7 Feb 2018 07:49:58 +0000 "Tan, Jianfeng" wrote: > > -----Original Message----- > > From: Paolo Bonzini [mailto:pbonzini@redhat.com] > > Sent: Tuesday, February 6, 2018 1:32 AM > > To: Igor Mammedov > > Cc: Tan, Jianfeng; qemu-devel@nongnu.org; Jason Wang; Maxime Coquelin; > > Michael S . Tsirkin > > Subject: Re: [Qemu-devel] [RFC] exec: eliminate ram naming issue as > > migration > >=20 > > On 05/02/2018 18:15, Igor Mammedov wrote: =20 > > >>> > > >>> Then we would have both ram block named pc.ram: > > >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 Block Name=C2=A0=C2=A0=C2=A0 PSize > > >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 pc.ram=C2=A0= =C2=A0=C2=A0=C2=A0 4 KiB > > >>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 /objects/pc.ram=C2=A0=C2=A0=C2=A0 2 = MiB > > >>> > > >>> But I assume it's a corner case which not really happen. =20 > > >> Yeah, you're right. :/ I hadn't thought of hotplug. It can happen = indeed. =20 > > > > > > perhaps we should fail object_add memory-backend-foo if it resulted > > > in creating ramblock with duplicate id =20 > >=20 > > Note that it would only be duplicated with Jianfeng's patch. So I'm > > worried that his patch is worse than what we have now, because it may > > create conflicts with system RAMBlock names are not necessarily > > predictable. Right now, -object creates RAMBlock names that are nicely > > constrained within /object/. =20 >=20 > So we are trading off between the benefit it takes and the bad effect it = brings. >=20 > I'm wondering if the above example is the only failed case this patch lea= ds to, i.e, only there is a ram named "pc.ram" and "/object/pc.ram" in the = src VM? >=20 > Please also consider the second option, that adding an alias name for RAM= Block; I'm not a big fan for that one, as it just pushes the problem to Ope= nStack/Libvirt. looking at provided CLI examples it's configuration issue on src and dst, one shall not mix numa and non numa variants. > Or any other suggestions? Fix configuration, namely dst side of it (i.e. use the same -m only variant without -numa as it's on src). BTW, what are you trying to achieve adding -numa on dst? > Thanks, > Jianfeng