tree f3f3545a49b6fab3f13623d0f491e6d2d4b0d139
parent 5d84e4bee044a740729ac172e684e743f5ad50fb
author Brian King <brking@linux.vnet.ibm.com> 1229598826 +0000
committer Paul Mackerras <paulus@samba.org> 1229829675 +1100

powerpc: Disable Collaborative Memory Manager for kdump

When running Active Memory Sharing, the Collaborative Memory Manager
(CMM) may mark some pages as "loaned" with the hypervisor.
Periodically, the CMM will query the hypervisor for a loan request,
which is a single signed value.  When kexec'ing into a kdump kernel,
the CMM driver in the kdump kernel is not aware of the pages the
previous kernel had marked as "loaned", so the hypervisor and the CMM
driver are out of sync.  This results in the CMM driver getting a
negative loan request, which can then get treated as a large unsigned
value and can cause kdump to hang due to the CMM driver inflating too
large.  Since there really is no clean way for the CMM driver in the
kdump kernel to clean this up, simply disable CMM in the kdump kernel.
This fixes hangs we were seeing doing kdump with AMS.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>