Re: [PATCH V3] xen/balloon: Memory hotplug support for Xen balloondriver

From: Vasiliy G Tolstov
Date: Wed May 18 2011 - 03:25:18 EST


On Wed, 2011-05-18 at 08:21 +0100, Ian Campbell wrote:
> On Wed, 2011-05-18 at 07:57 +0100, Vasiliy G Tolstov wrote:
> > On Tue, 2011-05-17 at 23:44 +0200, Daniel Kiper wrote:
> > > + Memory could be hotplugged in following steps:
> > > +
> > > + 1) dom0: xl mem-max <domU> <maxmem>
> > > + where <maxmem> is >= requested memory size,
> > > +
> > > + 2) dom0: xl mem-set <domU> <memory>
> > > + where <memory> is requested memory size; alternatively memory
> > > + could be added by writing proper value to
> > > + /sys/devices/system/xen_memory/xen_memory0/target or
> > > + /sys/devices/system/xen_memory/xen_memory0/target_kb on dumU,
> > > +
> > > + 3) domU: for i in /sys/devices/system/memory/memory*/state; do \
> > > + [ "`cat "$i"`" = offline ] && echo online > "$i"; done
> > > +
>
> > Very good. Is that possible to eliminate step 3 ? And do it automatic if
> > domU runs with specific xen balloon param?
>
> When we faced the same question WRT VCPU hotplug we ended up using a
> udev rule. Presumably the same could be done here. In the VCPU case the
> rule is:
>
> ACTION=="add", SUBSYSTEM=="cpu", RUN+="/bin/sh -c '[ ! -e /sys$devpath/online ] || echo 1 > /sys$devpath/online'"
>
> Presumably the memory one will be broadly similar.
>
> Ian.
>

Ok. very good solution. Thank's.

--
Vasiliy G Tolstov <v.tolstov@xxxxxxxxx>
Selfip.Ru

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