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authorBrian King <brking@linux.vnet.ibm.com>2008-12-18 06:13:46 -0500
committerPaul Mackerras <paulus@samba.org>2008-12-20 22:21:15 -0500
commit2218108e182fd8a6d9106077833ed7ad05fc8e75 (patch)
treef3f3545a49b6fab3f13623d0f491e6d2d4b0d139
parent5d84e4bee044a740729ac172e684e743f5ad50fb (diff)
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>
-rw-r--r--arch/powerpc/platforms/pseries/Kconfig2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
index 97619fd51e39..ddc2a307cd50 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -54,7 +54,7 @@ config PPC_SMLPAR
54 54
55config CMM 55config CMM
56 tristate "Collaborative memory management" 56 tristate "Collaborative memory management"
57 depends on PPC_SMLPAR 57 depends on PPC_SMLPAR && !CRASH_DUMP
58 default y 58 default y
59 help 59 help
60 Select this option, if you want to enable the kernel interface 60 Select this option, if you want to enable the kernel interface