[libvirt] getFreeMemory reporting incorrectly?

[Hany Fahim]

Thanks Daniel,
Is it fair to assume this fix may appear in the next release of libvirt?

Hany

On Thu, Jun 11, 2009 at 2:28 PM, Daniel P. Berrange <berrange at redhat.com>wrote:

> On Thu, Jun 11, 2009 at 02:13:17PM -0400, Hany Fahim wrote:
> > My apologies. Here it is:
> > Xen 3.3:
> >
> > [root at node1 ~]# xm info
> > total_memory           : 3063
> > free_memory            : 128
> > node_to_cpu            : node0:0-1
> > node_to_memory         : node0:128
> > xen_major              : 3
> > xen_minor              : 3
> > xen_extra              : .1
>
> >
> > Xen 3.0.3:
> >
> > [root at node2 ~]# xm info
> > total_memory           : 2046
> > free_memory            : 256
> > node_to_cpu            : node0:0
> > xen_major              : 3
> > xen_minor              : 1
> > xen_extra              : .2-128.1.6.el5
>
>
> This shows that the Hypervisor  is giving correct info back with both
> versions. So the problem must be at the libvirt space, and I believe
> I know what the problem is.
>
> The version of Xen in RHEL5 has
>
> struct xen_sysctl_availheap {
>    /* IN variables. */
>    uint32_t min_bitwidth;  /* Smallest address width (zero if don't care).
> */
>    uint32_t max_bitwidth;  /* Largest address width (zero if don't care).
> */
>    int32_t  node;          /* NUMA node of interest (-1 for all nodes). */
>    /* OUT variables. */
>    uint64_t avail_bytes;   /* Bytes available in the specified region. */
> };
>
> While upstream Xen has
>
> struct xen_sysctl_availheap {
>    /* IN variables. */
>    uint32_t min_bitwidth;  /* Smallest address width (zero if don't care).
> */
>    uint32_t max_bitwidth;  /* Largest address width (zero if don't care).
> */
>    int32_t  node;          /* NUMA node of interest (-1 for all nodes). */
>    /* OUT variables. */
>    uint64_aligned_t avail_bytes;/* Bytes available in the specified region.
> */
> };
>
> Notice the 'avail_bytes' field is now aligned, so its 4 bytes further
> down from where libvirt is expecting it to be.
>
> We'll have to provide a fix in libvirt to use the new alignment for
> newer Xen.
>
> Regards,
> Daniel
> --
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