Disable transparent hugepages in second kernel
    
    Transparent hugepages are on by default. Disable it in kdump kernel by
    adding the parameter 'transparent_hugepage=never'. This might help us
    with some of the memory issues we are facing.
    
    From my test on two arch, not only there are no any bad effect on saving vmcore
    after turn off THP, but also we can get more 'MemAvailable:' in the kdump kernel.
    
    1)x86_64
    without the parameter
    =====================
    kdump:/# cat /proc/cmdline
    BOOT_IMAGE=/vmlinuz-3.10.0-229.el7.x86_64 root=/dev/mapper/rhel_ibm--x3250m4--01-root ro rd.lvm.lv=rhel_ibm-x3250m4-01/swap console=ttyS0,115200n8 rd.lvm.lv=rhel_ibm-x3250m4-01/root LANG=en_US.UTF-8 irqpoll nr_cpus=1 reset_devices cgroup_disable=memory mce=off numa=off udev.children-max=2 panic=10 rootflags=nofail acpi_no_memhotplug disable_cpu_apicid=0 elfcorehdr=869764K
    
    kdump:/# cat /proc/meminfo
    MemTotal:         145492 kB
    MemFree:           68284 kB
    MemAvailable:     111632 kB  <<------
    Buffers:              36 kB
    Cached:            48184 kB
    ...
    
    added the parameter
    =====================
    kdump:/# cat /proc/cmdline
    BOOT_IMAGE=/vmlinuz-3.10.0-229.el7.x86_64 root=/dev/mapper/rhel_ibm--x3250m4--01-root ro rd.lvm.lv=rhel_ibm-x3250m4-01/swap console=ttyS0,115200n8 rd.lvm.lv=rhel_ibm-x3250m4-01/root LANG=en_US.UTF-8 irqpoll nr_cpus=1 reset_devices cgroup_disable=memory mce=off numa=off udev.children-max=2 panic=10 rootflags=nofail acpi_no_memhotplug transparent_hugepage=never disable_cpu_apicid=0 elfcorehdr=869764K
    
    kdump:/# cat /proc/meminfo
    MemTotal:         145492 kB
    MemFree:           68388 kB
    MemAvailable:     111728 kB  <<-------
    ...
    VmallocChunk:   34359659520 kB
    HardwareCorrupted:     0 kB
    AnonHugePages:         0 kB
    ...
    
    2)ppc64
    without the parameter
    ====================
    kdump:/# cat /proc/cmdline
    BOOT_IMAGE=/vmlinuz-3.10.0-229.el7.ppc64 root=/dev/mapper/rhel_ibm--p8--05--lp6-root ro rd.lvm.lv=rhel_ibm-p8-05-lp6/root rd.lvm.lv=rhel_ibm-p8-05-lp6/swap LANG=en_US.UTF-8 irqpoll maxcpus=1 noirqdistrib reset_devices cgroup_disable=memory numa=off udev.children-max=2 ehea.use_mcs=0 panic=10 rootflags=nofail kvm_cma_resv_ratio=0 elfcorehdr=154880K
    
    kdump:/# cat /proc/meminfo
    MemTotal:         480832 kB
    MemFree:          293952 kB
    MemAvailable:     427840 kB  <<--------
    mallocUsed:       23680 kB
    VmallocChunk:   8589901824 kB
    HardwareCorrupted:     0 kB
    AnonHugePages:         0 kB
    ...
    
    added the parameter
    ===================
    kdump:/# cat /proc/cmdline
    BOOT_IMAGE=/vmlinuz-3.10.0-229.el7.ppc64 root=/dev/mapper/rhel_ibm--p8--05--lp6-root ro rd.lvm.lv=rhel_ibm-p8-05-lp6/root rd.lvm.lv=rhel_ibm-p8-05-lp6/swap LANG=en_US.UTF-8 irqpoll maxcpus=1 noirqdistrib reset_devices cgroup_disable=memory numa=off udev.children-max=2 ehea.use_mcs=0 panic=10 rootflags=nofail kvm_cma_resv_ratio=0 transparent_hugepage=never elfcorehdr=154880K
    
    kdump:/# cat /proc/meminfo
    MemTotal:         480832 kB
    MemFree:          294592 kB
    MemAvailable:     428480 kB  <<-------
    ...
    HugePages_Total:       0
    
    Signed-off-by: Li Wang <liwang@redhat.com>
    Acked-by: Minfei Huang <mhuang@redhat.com>
    Acked-by: Baoquan He <bhe@redaht.com>