Libguestfs - Jun 2016 - Re: [PATCH 1/2] increase the default memory size to 768 MB

On Sat, Jun 11, 2016 at 08:51:56PM +0300, Pavel Butsykin
wrote:
> The appliance memory size of 500 MB is insufficient in certain scenarios. 
In
> partiuclar, semodule (which may be called by a guest tools uninstaller)
often
> triggers OOM (see https://bugzilla.redhat.com/426775)
> 
> Increase it to 768 MB.
> 
> Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
> ---
>  src/guestfs-internal.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h
> index 03f1034..1d1b996 100644
> --- a/src/guestfs-internal.h
> +++ b/src/guestfs-internal.h
> @@ -93,7 +93,7 @@
>  
>  /* The default and minimum memory size for most users. */
>  #ifndef DEFAULT_MEMSIZE
> -#  define DEFAULT_MEMSIZE 500
> +#  define DEFAULT_MEMSIZE 768
>  #endif
>  #ifndef MIN_MEMSIZE
>  #  define MIN_MEMSIZE 128
If only we had a more sensible way to allocate memory :-(

Anyway, this patch needs to remove the earlier lines which set
DEFAULT_MEMSIZE to 768 on __powerpc__ and __aarch64__.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v

On Sat, Jun 11, 2016 at 09:35:40PM +0100, Richard W.M. Jones
wrote:
> On Sat, Jun 11, 2016 at 08:51:56PM +0300, Pavel Butsykin wrote:
> > The appliance memory size of 500 MB is insufficient in certain
scenarios.  In
> > partiuclar, semodule (which may be called by a guest tools
uninstaller) often
> > triggers OOM (see https://bugzilla.redhat.com/426775)
> > 
> > Increase it to 768 MB.
> > 
> > Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
> > ---
> >  src/guestfs-internal.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h
> > index 03f1034..1d1b996 100644
> > --- a/src/guestfs-internal.h
> > +++ b/src/guestfs-internal.h
> > @@ -93,7 +93,7 @@
> >  
> >  /* The default and minimum memory size for most users. */
> >  #ifndef DEFAULT_MEMSIZE
> > -#  define DEFAULT_MEMSIZE 500
> > +#  define DEFAULT_MEMSIZE 768
> >  #endif
> >  #ifndef MIN_MEMSIZE
> >  #  define MIN_MEMSIZE 128
> 
> If only we had a more sensible way to allocate memory :-(
> 
> Anyway, this patch needs to remove the earlier lines which set
> DEFAULT_MEMSIZE to 768 on __powerpc__ and __aarch64__.
When I thought about this a bit more, I think what you want is to just
increase the memory limit for virt-v2v.  How about the attached?
(Only compile tested.)

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org

On Tue, Jun 14, 2016 at 11:56:16AM +0300, Pavel Butsykin
wrote:
> Yes, that's right, I'm just here to follow the rule - the simpler
the
> better :) Your solution is more correct, because it allows to go to the
> next step, to make this knowledge outward. The caller may know better
> need extra memory or not. For example, in the context of this issue, we
> do not need additional memory for windows guests.
FWIW this is the final patch I went with:

https://github.com/libguestfs/libguestfs/commit/08f82f2e3d6975b72340dd59f438862e152a15ef

It will allocate 800MB on x86-64.  Note that actual usage should be
smaller since KVM will allocate the RAM only if the guest tries to use
it.  Also we have a few tricks coming soon like using DAX in the next
version of qemu[1].

It's difficult to make the amount vary by guest type, since virt-v2v
doesn't know the guest type until it has inspected it, which happens
after the appliance has been launched.

Rich.

[1] https://www.redhat.com/archives/libguestfs/2016-May/msg00138.html

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org