0aada50b66
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>
36 lines
1.4 KiB
Plaintext
36 lines
1.4 KiB
Plaintext
# Kernel Version string for the -kdump kernel, such as 2.6.13-1544.FC5kdump
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# If no version is specified, then the init script will try to find a
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# kdump kernel with the same version number as the running kernel.
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KDUMP_KERNELVER=""
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# The kdump commandline is the command line that needs to be passed off to
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# the kdump kernel. This will likely match the contents of the grub kernel
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# line. For example:
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# KDUMP_COMMANDLINE="ro root=LABEL=/"
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# Dracut depends on proper root= options, so please make sure that appropriate
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# root= options are copied from /proc/cmdline. In general it is best to append
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# command line options using "KDUMP_COMMANDLINE_APPEND=".
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# If a command line is not specified, the default will be taken from
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# /proc/cmdline
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KDUMP_COMMANDLINE=""
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# This variable lets us append arguments to the current kdump commandline
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# As taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
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KDUMP_COMMANDLINE_APPEND="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"
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# Any additional kexec arguments required. In most situations, this should
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# be left empty
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#
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# Example:
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# KEXEC_ARGS="--elf32-core-headers"
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KEXEC_ARGS=""
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#Where to find the boot image
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#KDUMP_BOOTDIR="/boot"
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#What is the image type used for kdump
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KDUMP_IMG="vmlinuz"
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#What is the images extension. Relocatable kernels don't have one
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KDUMP_IMG_EXT=""
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