Linux 内核参数：watermark_boost_factor

源码基于：Linux 5.4

针对节点 /proc/sys/vm/watermark_boost_factor

0. 官方描述

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

This factor controls the level of reclaim when memory is being fragmented.
It defines the percentage of the high watermark of a zone that will be
reclaimed if pages of different mobility are being mixed within pageblocks.
The intent is that compaction has less work to do in the future and to
increase the success rate of future high-order allocations such as SLUB
allocations, THP and hugetlbfs pages.

To make it sensible with respect to the watermark_scale_factor
parameter, the unit is in fractions of 10,000. The default value of
15,000 on !DISCONTIGMEM configurations means that up to 150% of the high
watermark will be reclaimed in the event of a pageblock being mixed due
to fragmentation. The lev