Home / server / Questions / 50335
In Process
Nikolai Prokoschenko
Asked: 2009-08-06 05:19:44 +0800 CST

Crashing HVM domain, what do I do?

  • 772

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...

xen domu

2 Answers

  1. There's some good detail here:

    http://lists.xensource.com/archives/html/xen-devel/2008-12/msg01030.html

    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.

    • 1

  2. 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.

    • 1