My DomUs on a Xen 3.4 on an RHEL5 are crashing when too much memory is needed:

(XEN) p2m_pod_demand_populate: Out of populate-on-demand memory!
(XEN) domain_crash called from p2m.c:1091
(XEN) Domain 15 (vcpu#3) crashed on cpu#2:
(XEN) ----[ Xen-3.4.0  x86_64  debug=n  Not tainted ]----
(XEN) CPU:    2
(XEN) RIP:    0010:[<ffffffff80062c02>]
(XEN) RFLAGS: 0000000000010216   CONTEXT: hvm guest
(XEN) rax: 0000000000000000   rbx: 0000000000000001   rcx: 000000000000003f
(XEN) rdx: 0000000004812000   rsi: ffff810001000000   rdi: ffff810004812000
(XEN) rbp: 0000000000000282   rsp: ffff810007635cf0   r8:  ffff810037c0288e
(XEN) r9:  00000000000023e1   r10: 0000000000000000   r11: 0000000000000001
(XEN) r12: ffff81000000cb00   r13: ffff8100007e43f0   r14: ffff81000000fc10
(XEN) r15: 00000000000280d2   cr0: 0000000080050033   cr4: 00000000000006e0
(XEN) cr3: 0000000006760000   cr2: 0000000003d47078
(XEN) ds: 0000   es: 0000   fs: 0000   gs: 0000   ss: 0000   cs: 0010

Can I disable populate-on-demand for HVM somehow? Xen 3.3 didn't exhibit such behaviour...


There's some good detail here:


Which seems to indicate this only happens when you overcommit. Of course if your domU's are linux you really should consider running in paravirt mode for the performance benefits.


Easy way:

in your config make maxmem=memory, which disables the PoD driver.

Otherwise you will need to install a balloon driver in the guest OS.

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