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# change the minimum size of the hugepage pool.
# 2G VPP, 16x2G for Fullbox VM, 2G reserve
vm.nr_hugepages={{ sysctl.vm.nr_hugepages }}
# this file contains the maximum number of memory map areas a process
# may have. memory map areas are used as a side-effect of calling
# malloc, directly by mmap and mprotect, and also when loading shared
# libraries.
#
# while most applications need less than a thousand maps, certain
# programs, particularly malloc debuggers, may consume lots of them,
# e.g., up to one or two maps per allocation.
# must be greater than or equal to (2 * vm.nr_hugepages).
vm.max_map_count={{ sysctl.vm.max_map_count }}
# hugetlb_shm_group contains group id that is allowed to create sysv
# shared memory segment using hugetlb page.
vm.hugetlb_shm_group=0
# this control is used to define how aggressive the kernel will swap
# memory pages. higher values will increase agressiveness, lower values
# decrease the amount of swap. a value of 0 instructs the kernel not to
# initiate swap until the amount of free and file-backed pages is less
# than the high water mark in a zone.
vm.swappiness=0
# this parameter can be used to control the nmi watchdog
# (i.e. the hard lockup detector) on x86 systems.
#
# 0 - disable the hard lockup detector
# 1 - enable the hard lockup detector
#
# the hard lockup detector monitors each cpu for its ability to respond to
# timer interrupts. the mechanism utilizes cpu performance counter registers
# that are programmed to generate non-maskable interrupts (nmis) periodically
# while a cpu is busy. hence, the alternative name 'nmi watchdog'.
#
# the nmi watchdog is disabled by default if the kernel is running as a guest
# in a kvm virtual machine. this default can be overridden by adding
#kernel. nmi_watchdog=1
# shared memory max must be greator or equal to the total size of hugepages.
# for 2mb pages, totalhugepagesize = vm.nr_hugepages * 2 * 1024 * 1024
# if the existing kernel.shmmax setting (cat /sys/proc/kernel/shmmax)
# is greater than the calculated totalhugepagesize then set this parameter
# to current shmmax value.
kernel.shmmax=8589934592
# this option can be used to select the type of process address
# space randomization that is used in the system, for architectures
# that support this feature.
# 0 - turn the process address space randomization off. this is the
# default for architectures that do not support this feature anyways,
# and kernels that are booted with the "norandmaps" parameter.
kernel.randomize_va_space=0
# this parameter can be used to control the soft lockup detector.
#
# 0 - disable the soft lockup detector
# 1 - enable the soft lockup detector
#
# the soft lockup detector monitors cpus for threads that are hogging the cpus
# without rescheduling voluntarily, and thus prevent the 'watchdog/n' threads
# from running. the mechanism depends on the cpus ability to respond to timer
# interrupts which are needed for the 'watchdog/n' threads to be woken up by
# the watchdog timer function, otherwise the nmi watchdog - if enabled - can
# detect a hard lockup condition.
#kernel.soft_watchdog=0
# this value can be used to control on which cpus the watchdog may run.
# the default cpumask is all possible cores, but if no_hz_full is
# enabled in the kernel config, and cores are specified with the
# nohz_full= boot argument, those cores are excluded by default.
# offline cores can be included in this mask, and if the core is later
# brought online, the watchdog will be started based on the mask value.
#
# typically this value would only be touched in the nohz_full case
# to re-enable cores that by default were not running the watchdog,
# if a kernel lockup was suspected on those cores.
kernel.watchdog_cpumask={{ sysctl.kernel.watchdog_cpumask }}
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