* [Qemu-devel] ballooning not working on hotplugged pc-dimm [not found] <0a98da72-f316-4e2b-8327-201f85a6e879@mailpro> @ 2014-09-09 3:05 ` Alexandre DERUMIER 2014-09-10 9:00 ` zhanghailiang 0 siblings, 1 reply; 6+ messages in thread From: Alexandre DERUMIER @ 2014-09-09 3:05 UTC (permalink / raw) To: qemu-devel Hello, I was playing with pc-dimm hotplug, and I notice that balloning is not working on memory space of pc-dimm devices. example: qemu -m size=1024,slots=255,maxmem=15000M #free -m : 1024M -> qmp balloon 512M #free -m : 512M -> hotplug pc-dimm 1G: #free -m : 1512M (This is the same behavior if qemu is started with pc-dimm devices) qemu 2.1 Guest kernel : 3.12. Does it need a guest balloon module update ? Regards, Alexandre Derumier ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] ballooning not working on hotplugged pc-dimm 2014-09-09 3:05 ` [Qemu-devel] ballooning not working on hotplugged pc-dimm Alexandre DERUMIER @ 2014-09-10 9:00 ` zhanghailiang 2014-09-11 1:57 ` Michael R. Hines 0 siblings, 1 reply; 6+ messages in thread From: zhanghailiang @ 2014-09-10 9:00 UTC (permalink / raw) To: Alexandre DERUMIER; +Cc: qemu-devel On 2014/9/9 11:05, Alexandre DERUMIER wrote: > Hello, > > I was playing with pc-dimm hotplug, and I notice that balloning is not working on > memory space of pc-dimm devices. > > example: > > qemu -m size=1024,slots=255,maxmem=15000M > > #free -m : 1024M > -> qmp balloon 512M > #free -m : 512M > > -> hotplug pc-dimm 1G: > > #free -m : 1512M > > > (This is the same behavior if qemu is started with pc-dimm devices) > > > qemu 2.1 > Guest kernel : 3.12. > > > > Does it need a guest balloon module update ? > > Regards, > > Alexandre Derumier > > > Hi, I noticed this fault also;-), this is a bug in qemu, And some work in process... Actually in QEMU the hotplugged memory(named hotplug-memory) is distinguished from the common memory(named pc.ram). When do balloon action, QEMU wrongly stats the ram_size. I will send a patch series which also include other bug fix for the memory hotplug. Thanks, zhanghailiang ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] ballooning not working on hotplugged pc-dimm 2014-09-10 9:00 ` zhanghailiang @ 2014-09-11 1:57 ` Michael R. Hines 2014-09-11 6:22 ` Paolo Bonzini 0 siblings, 1 reply; 6+ messages in thread From: Michael R. Hines @ 2014-09-11 1:57 UTC (permalink / raw) To: zhanghailiang, Alexandre DERUMIER; +Cc: hinesmr, qemu-devel On 09/10/2014 05:00 PM, zhanghailiang wrote: > On 2014/9/9 11:05, Alexandre DERUMIER wrote: >> Hello, >> >> I was playing with pc-dimm hotplug, and I notice that balloning is >> not working on >> memory space of pc-dimm devices. >> >> example: >> >> qemu -m size=1024,slots=255,maxmem=15000M >> >> #free -m : 1024M >> -> qmp balloon 512M >> #free -m : 512M >> >> -> hotplug pc-dimm 1G: >> >> #free -m : 1512M >> >> >> (This is the same behavior if qemu is started with pc-dimm devices) >> >> >> qemu 2.1 >> Guest kernel : 3.12. >> >> >> >> Does it need a guest balloon module update ? >> >> Regards, >> >> Alexandre Derumier >> >> >> > Hi, > > I noticed this fault also;-), this is a bug in qemu, And some work in > process... > > Actually in QEMU the hotplugged memory(named hotplug-memory) is > distinguished > from the common memory(named pc.ram). When do balloon action, QEMU > wrongly > stats the ram_size. > > I will send a patch series which also include other bug fix for the > memory hotplug. > > Thanks, > zhanghailiang > > > Why does hotplugging use a different name? This also affects RDMA live migration - we are explicitly looking up "pc.ram" ram blocks and pinning them for memory registration with Linux. - Michael ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] ballooning not working on hotplugged pc-dimm 2014-09-11 1:57 ` Michael R. Hines @ 2014-09-11 6:22 ` Paolo Bonzini 2014-09-11 6:27 ` Michael R. Hines 0 siblings, 1 reply; 6+ messages in thread From: Paolo Bonzini @ 2014-09-11 6:22 UTC (permalink / raw) To: Michael R. Hines, zhanghailiang, Alexandre DERUMIER; +Cc: hinesmr, qemu-devel Il 11/09/2014 03:57, Michael R. Hines ha scritto: >> > > Why does hotplugging use a different name? > > This also affects RDMA live migration - we are explicitly looking up > "pc.ram" ram blocks and pinning them for memory registration with Linux. Are we? I cannot see any code that special cases pc.ram (it only appears in a couple of comments). It'd also be surprising to see that escaping review. :) Paolo ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] ballooning not working on hotplugged pc-dimm 2014-09-11 6:22 ` Paolo Bonzini @ 2014-09-11 6:27 ` Michael R. Hines 2014-09-11 6:33 ` zhanghailiang 0 siblings, 1 reply; 6+ messages in thread From: Michael R. Hines @ 2014-09-11 6:27 UTC (permalink / raw) To: Paolo Bonzini, zhanghailiang, Alexandre DERUMIER; +Cc: hinesmr, qemu-devel On 09/11/2014 02:22 PM, Paolo Bonzini wrote: > Il 11/09/2014 03:57, Michael R. Hines ha scritto: >> Why does hotplugging use a different name? >> >> This also affects RDMA live migration - we are explicitly looking up >> "pc.ram" ram blocks and pinning them for memory registration with Linux. > Are we? I cannot see any code that special cases pc.ram (it only > appears in a couple of comments). It'd also be surprising to see that > escaping review. :) > > Paolo > You're absolutely right =) I was thinking about old code. We loop through all the ram blocks. Good sanity check, though =) - Michael ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [Qemu-devel] ballooning not working on hotplugged pc-dimm 2014-09-11 6:27 ` Michael R. Hines @ 2014-09-11 6:33 ` zhanghailiang 0 siblings, 0 replies; 6+ messages in thread From: zhanghailiang @ 2014-09-11 6:33 UTC (permalink / raw) To: Michael R. Hines; +Cc: Paolo Bonzini, hinesmr, qemu-devel, Alexandre DERUMIER On 2014/9/11 14:27, Michael R. Hines wrote: > On 09/11/2014 02:22 PM, Paolo Bonzini wrote: >> Il 11/09/2014 03:57, Michael R. Hines ha scritto: >>> Why does hotplugging use a different name? >>> >>> This also affects RDMA live migration - we are explicitly looking up >>> "pc.ram" ram blocks and pinning them for memory registration with Linux. >> Are we? I cannot see any code that special cases pc.ram (it only >> appears in a couple of comments). It'd also be surprising to see that >> escaping review. :) >> >> Paolo >> > > > You're absolutely right =) I was thinking about old code. We loop through all the ram blocks. > > Good sanity check, though =) > > - Michael > > > Hmm, in this case, it is better to remove this confused comments;-) ^ permalink raw reply [flat|nested] 6+ messages in thread
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2014-09-09 3:05 ` [Qemu-devel] ballooning not working on hotplugged pc-dimm Alexandre DERUMIER
2014-09-10 9:00 ` zhanghailiang
2014-09-11 1:57 ` Michael R. Hines
2014-09-11 6:22 ` Paolo Bonzini
2014-09-11 6:27 ` Michael R. Hines
2014-09-11 6:33 ` zhanghailiang
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