[pve-devel] CPU and Memory hot add

[Alexandre DERUMIER]

>>No they don't ;-) here an output of a running vm adding more memory: 

Could be interesting to see if they use acpi hotplug.
If yes, they should have somewhere an udev rules for memory hotplug. (and cpu hotplug too)

something like:"
"
# Hotplug physical memory
SUBSYSTEM=="memory", ACTION=="add", TEST=="state", ATTR{state}=="offline", \
 ATTR{state}="online"
"

maybe can you try to remove the udev rules, reboot, try to change memory size, and see if it's working or not





last qemu memory acpi hotplug v7 patches are here
http://qemu.11.n7.nabble.com/PATCH-00-27-RFC-v7-ACPI-memory-hotplug-td234477.html

Don't known about the stability, but maybe can you try them ?

----- Mail original ----- 

De: "Stefan Priebe" <s.priebe at profihost.ag> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Dimanche 16 Février 2014 21:55:47 
Objet: Re: [pve-devel] CPU and Memory hot add 


Am 15.02.2014 13:59, schrieb Alexandre DERUMIER: 
> cpu hot add is already implemented. (even in proxmox ;) 
> https://git.proxmox.com/?p=qemu-server.git;a=commit;h=838776ab650f0593b48c234070c1a189fdbd72c7 
> 
> cpu hot del is not yet implemented. (but they are some prelimary patches in the qemu mailing list) 
> 
> memory hotplug is not yet implemented. (should be ok for next qemu 2.0 release I think) 
> 
> But maybe they are cheating, like I do : just use ballonning with a fixed size ? 

No they don't ;-) here an output of a running vm adding more memory: 

[ 356.984360] Hotplug Mem Device 
[ 356.985973] init_memory_mapping: 0000000040000000-0000000080000000 
[ 356.986070] 0040000000 - 0080000000 page 1G 
[ 356.988604] [ffffea0001000000-ffffea00011fffff] PMD -> 
[ffff88003ce00000-ffff88003cffffff] on node 0 
[ 356.997027] [ffffea0001200000-ffffea00013fffff] PMD -> 
[ffff88003c800000-ffff88003c9fffff] on node 0 
[ 356.998495] [ffffea0001400000-ffffea00015fffff] PMD -> 
[ffff88003c600000-ffff88003c7fffff] on node 0 
[ 357.000084] [ffffea0001600000-ffffea00017fffff] PMD -> 
[ffff88003b000000-ffff88003b1fffff] on node 0 
[ 357.001459] [ffffea0001800000-ffffea00019fffff] PMD -> 
[ffff880034c00000-ffff880034dfffff] on node 0 
[ 357.004401] [ffffea0001a00000-ffffea0001dfffff] PMD -> 
[ffff88003c000000-ffff88003c3fffff] on node 0 
[ 357.007038] Hotplug Mem Device 
[ 357.024941] Built 1 zonelists in Node order, mobility grouping on. 
Total pages: 273785 
[ 357.024941] Policy zone: Normal 
[ 357.038623] init_memory_mapping: 0000000080000000-00000000c0000000 
[ 357.038636] 0080000000 - 00c0000000 page 1G 
[ 357.038782] [ffffea0001e00000-ffffea0001ffffff] PMD -> 
[ffff88003b400000-ffff88003b5fffff] on node 0 
[ 357.040088] [ffffea0002000000-ffffea00021fffff] PMD -> 
[ffff880047e00000-ffff880047ffffff] on node 0 
[ 357.040756] [ffffea0002200000-ffffea00025fffff] PMD -> 
[ffff88007fc00000-ffff88007fffffff] on node 0 
[ 357.044036] [ffffea0002600000-ffffea00029fffff] PMD -> 
[ffff88007f800000-ffff88007fbfffff] on node 0 
[ 357.062995] [ffffea0002a00000-ffffea0002dfffff] PMD -> 
[ffff88007f400000-ffff88007f7fffff] on node 0 
[ 357.072594] Hotplug Mem Device 
[ 357.119388] init_memory_mapping: 0000000100000000-0000000140000000 
[ 357.119388] 0100000000 - 0140000000 page 1G 
[ 357.121941] [ffffea0002e00000-ffffea00041fffff] PMD -> 
[ffff88007f000000-ffff88007f3fffff] on node 0 
[ 357.125199] [ffffea0004200000-ffffea00045fffff] PMD -> 
[ffff880087800000-ffff880087bfffff] on node 0 
[ 357.128890] [ffffea0004600000-ffffea00049fffff] PMD -> 
[ffff880087400000-ffff8800877fffff] on node 0 
[ 357.132014] [ffffea0004a00000-ffffea0004dfffff] PMD -> 
[ffff880087000000-ffff8800873fffff] on node 0 
[ 357.135378] Hotplug Mem Device 
[ 357.170010] init_memory_mapping: 0000000140000000-0000000180000000 
[ 357.170010] 0140000000 - 0180000000 page 1G 
[ 357.170174] [ffffea0004e00000-ffffea00051fffff] PMD -> 
[ffff880086c00000-ffff880086ffffff] on node 0 
[ 357.172473] [ffffea0005200000-ffffea00055fffff] PMD -> 
[ffff880127c00000-ffff880127ffffff] on node 0 
[ 357.175795] [ffffea0005600000-ffffea00059fffff] PMD -> 
[ffff880127800000-ffff880127bfffff] on node 0 
[ 357.180010] [ffffea0005a00000-ffffea0005dfffff] PMD -> 
[ffff880127400000-ffff8801277fffff] on node 0 
[ 357.195142] Hotplug Mem Device 
[ 357.195409] init_memory_mapping: 0000000180000000-00000001c0000000 
[ 357.195409] 0180000000 - 01c0000000 page 1G 
[ 357.197770] [ffffea0005e00000-ffffea00061fffff] PMD -> 
[ffff880127000000-ffff8801273fffff] on node 0 
[ 357.199525] [ffffea0006200000-ffffea00063fffff] PMD -> 
[ffff880137e00000-ffff880137ffffff] on node 0 
[ 357.202982] [ffffea0006400000-ffffea00067fffff] PMD -> 
[ffff880137800000-ffff880137bfffff] on node 0 
[ 357.206225] [ffffea0006800000-ffffea0006bfffff] PMD -> 
[ffff880137400000-ffff8801377fffff] on node 0 
[ 357.210314] Hotplug Mem Device 
[ 357.280089] init_memory_mapping: 00000001c0000000-0000000200000000 
[ 357.280089] 01c0000000 - 0200000000 page 1G 
[ 357.280295] [ffffea0006c00000-ffffea0006ffffff] PMD -> 
[ffff880137000000-ffff8801373fffff] on node 0 
[ 357.280898] [ffffea0007000000-ffffea00073fffff] PMD -> 
[ffff8801b7c00000-ffff8801b7ffffff] on node 0 
[ 357.284138] [ffffea0007400000-ffffea00077fffff] PMD -> 
[ffff8801b7800000-ffff8801b7bfffff] on node 0 
[ 357.290084] [ffffea0007800000-ffffea0007bfffff] PMD -> 
[ffff8801b7400000-ffff8801b77fffff] on node 0 

Stefan 

> 
> ----- Mail original ----- 
> 
> De: "Stefan Priebe" <s.priebe at profihost.ag> 
> À: pve-devel at pve.proxmox.com 
> Envoyé: Vendredi 14 Février 2014 21:18:47 
> Objet: [pve-devel] CPU and Memory hot add 
> 
> Hi, 
> 
> while browsing the web, i found profitbricks, which is active in germany 
> and the us (http://www.profitbricks.com/technical-info). 
> 
> They use KVM and offer memory and cpu hot add on the fly? Anybody an 
> idea how this works if kvm does not already support it? 
> 
> Greets, 
> Stefan 
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