How could I allocate a huge memory in rtdm driver?

[孙世龙]

Hi,
     I am using xenomai 3.1.

     How could I allocate a huge memory which may be larger then 50MB in
rtdm driver?

     I have tried rtdm_malloc function,but it returns NULL.

    To provide the operating system a large amount of free memory, I do
this test when the ubuntu is started at once in vmware.

    Best regards.