> On December 13, 2016 at 4:12 PM Alexandre DERUMIER <aderum...@odiso.com> > wrote: > > > I have asked to user to modprobe vhost module with region at 509, seem to > works fine. > > maybe can we force it in kernel directly ?
yes, seems to be easy: drivers/vhost/vhost.c:static ushort max_mem_regions = 64; What value should we set exactly? Any drawbacks? > > > ----- Mail original ----- > De: "aderumier" <aderum...@odiso.com> > À: "pve-devel" <pve-devel@pve.proxmox.com> > Envoyé: Lundi 12 Décembre 2016 19:46:56 > Objet: Re: [pve-devel] qemu memory hotplug limited to 64 dimm > > also here: > https://patchwork.kernel.org/patch/5825741/ > > > Seem that increasing regions decrease performance, because of extra lookups. > (I think with more regions, it's some kind of tree, where your need to lookup > first the parent region, then the child region) > > > ----- Mail original ----- > De: "aderumier" <aderum...@odiso.com> > À: "pve-devel" <pve-devel@pve.proxmox.com> > Cc: "dietmar" <diet...@proxmox.com> > Envoyé: Lundi 12 Décembre 2016 19:42:03 > Objet: Re: [pve-devel] qemu memory hotplug limited to 64 dimm > > I found some kernel patch to bump it to 509 (seem that another kvm fixed was > needed) > > http://www.spinics.net/lists/kvm/msg117654.html > > But I think it was never commited to the kernel. > > I'll try follow the discuss. > > ----- Mail original ----- > De: "aderumier" <aderum...@odiso.com> > À: "dietmar" <diet...@proxmox.com> > Cc: "pve-devel" <pve-devel@pve.proxmox.com> > Envoyé: Lundi 12 Décembre 2016 19:29:54 > Objet: Re: [pve-devel] qemu memory hotplug limited to 64 dimm > > >>Can't we simply increase that max_mem_regions default value? > > I'm trying to see why they have limited it to 64. > > maybe a qemu bug with previous qemu version? don't known. > > I have some big spare servers to test with 370G ram, i'll try to do test with > them. > > > ----- Mail original ----- > De: "dietmar" <diet...@proxmox.com> > À: "aderumier" <aderum...@odiso.com>, "pve-devel" <pve-devel@pve.proxmox.com> > Envoyé: Lundi 12 Décembre 2016 17:09:41 > Objet: Re: [pve-devel] qemu memory hotplug limited to 64 dimm > > Can't we simply increase that max_mem_regions default value? > > > > On December 12, 2016 at 4:54 PM Alexandre DERUMIER <aderum...@odiso.com> > > wrote: > > > > > > vhost 64 limit has been introduced here, because of qemu crash with bigger > > value > > > > https://patchwork.kernel.org/patch/6709021/ > > > > ----- Mail original ----- > > De: "aderumier" <aderum...@odiso.com> > > À: "pve-devel" <pve-devel@pve.proxmox.com> > > Envoyé: Lundi 12 Décembre 2016 16:51:11 > > Objet: [pve-devel] qemu memory hotplug limited to 64 dimm > > > > Hi, > > > > a proxmox user has reported problem to hotplug memory with high values (48G) > > > > > > https://forum.proxmox.com/threads/apt-get-upgrade-to-update-proxmox-server.30992/ > > > > > > > > > > Seem that qemu check about a vhost value > > > > https://lists.nongnu.org/archive/html/qemu-devel/2015-07/msg05998.html > > > > cat /sys/module/vhost/parameters/max_mem_regions > 64 (verified on my > > servers). > > > > > > I think this limit was not present when we have implemented hotplug. > > > > Not sure was we can do, but I think our method don't scale anymore :( > > > > Maybe should we introduce a new fixed "dimm size" option, to allow hotplug > > of > > more memory ? > > > > > > > > _______________________________________________ > > pve-devel mailing list > > pve-devel@pve.proxmox.com > > http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel > > > > _______________________________________________ > > pve-devel mailing list > > pve-devel@pve.proxmox.com > > http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel > > _______________________________________________ > pve-devel mailing list > pve-devel@pve.proxmox.com > http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel > > _______________________________________________ > pve-devel mailing list > pve-devel@pve.proxmox.com > http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel > > _______________________________________________ > pve-devel mailing list > pve-devel@pve.proxmox.com > http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel _______________________________________________ pve-devel mailing list pve-devel@pve.proxmox.com http://pve.proxmox.com/cgi-bin/mailman/listinfo/pve-devel