Linux 内核参数：min_free_kbytes

源码基于：Linux 5.4

针对节点 /proc/sys/vm/min_free_kbytes

0. 官方描述

/Documentation/admin-guide/sysctl/vm.rst

min_free_kbytes
===============

This is used to force the Linux VM to keep a minimum number
of kilobytes free.  The VM uses this number to compute a
watermark[WMARK_MIN] value for each lowmem zone in the system.
Each lowmem zone gets a number of reserved free pages based
proportionally on its size.

Some minimal amount of memory is needed to satisfy PF_MEMALLOC
allocations; if you set this to lower than 1024KB, your system will
become subtly broken, and prone to deadlock under high loads.

Setting this too high will OOM your machine instantly.

• 通过描述，该属性用以强制Linux VM 保留最小的free KB数，VM 通过该属性计算系统中每一个zone 的水位watermark[WMA