[Xen-devel] Live vm migration broken in latest xen-unstable

["sanjay kushwaha" <sanjay.kushwaha@xxxxxxxxx>]

Folks,
I am experiencing that live migration is not working in latest xen-unstable. I get the following message during migration

[root@pc5 ksanjay]# xm migrate --live 1 199.77.138.23
Error: /usr/lib/xen/bin/xc_save 18 1 0 0 1 failed
[root@pc5 ksanjay]#

I traced the problem to a function in xen named set_sh_allocation() in file xen/arch/x86/mm/shadow/common.c

tools/libxc/xc_linux_save.c:xc_linux_save() is called from the python script which makes the following hypercall

    if (live) {
        if (xc_shadow_control(xc_handle, dom,
                              XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
                              NULL, 0, NULL, 0, NULL) < 0) {
            ERR("Couldn't enable shadow mode");
            goto out;
        }
        last_iter = 0;
    } else {
-----------

this particular hypercall leads to the call of set_sh_allocation which fails in the following code

        if ( d->
arch.shadow.total_pages < pages )
        {
            /* Need to allocate more memory from domheap */
            pg = alloc_domheap_pages(NULL, SHADOW_MAX_ORDER, 0);
            if ( pg == NULL )
            {
                SHADOW_PRINTK("failed to allocate shadow pages.\n");
                return -ENOMEM;
            }

alloc_domheap_pages fails and returns NULL. however I think I have enough memory available so this function should not fail. 

Is there anybody else experiencing the same problem? Could someone please tell me how to fix it? 

Below is the xm info for my machine.

Thanks for your help,
Sanjay

[root@pc5 ~]# xm info
host                   : pc5
release                : 2.6.16.13-xen0
version                : #3 Fri Sep 1 17:13:13 EDT 2006
machine                : i686
nr_cpus                : 4
nr_nodes               : 1
sockets_per_node       : 2
cores_per_socket       : 1
threads_per_core       : 2
cpu_mhz                : 2791
hw_caps                : bfebfbff:00000000:00000000:00000080:00004400
total_memory           : 511
free_memory            : 1
xen_major              : 3
xen_minor              : 0
xen_extra              : -unstable
xen_caps               : xen-3.0-x86_32
xen_pagesize           : 4096
platform_params        : virt_start=0xfc000000
xen_changeset          : Mon Aug 28 08:08:41 2006 +0100 11267:68a1b61ecd28
cc_compiler            : gcc version 4.0.2 20051125 (Red Hat 4.0.2-8)
cc_compile_by          : root
cc_compile_domain      : 
netlab.cc.gatech.edu
cc_compile_date        : Fri Sep  1 17:12:28 EDT 2006
xend_config_format     : 2
[root@pc5 ~]#

-- 
----------------------
PhD Student, Georgia Tech
http://www.cc.gatech.edu/~ksanjay/
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel