From: Brian King Date: Thu, 18 Dec 2008 11:13:46 +0000 (+0000) Subject: powerpc: Disable Collaborative Memory Manager for kdump X-Git-Tag: v2.6.29-rc1~574^2~39 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=2218108e182fd8a6d9106077833ed7ad05fc8e75;p=linux-2.6-omap-h63xx.git 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 Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index 97619fd51e3..ddc2a307cd5 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -54,7 +54,7 @@ config PPC_SMLPAR config CMM tristate "Collaborative memory management" - depends on PPC_SMLPAR + depends on PPC_SMLPAR && !CRASH_DUMP default y help Select this option, if you want to enable the kernel interface