On Wed, Feb 05, 2020 at 05:36:44PM -0800, Mike Kravetz wrote: > The value of min_free_kbytes is calculated in two routines: > 1) init_per_zone_wmark_min based on available memory > 2) set_recommended_min_free_kbytes may reserve extra space for > THP allocations > > In both of these routines, a user defined min_free_kbytes value will > be overwritten if the value calculated in the code is larger. No message > is logged if the user value is overwritten. > > Change code to never overwrite user defined value. However, do log a > message (once per value) showing the value calculated in code. But what if the user set min_free_kbytes to, say, half of system memory, and then hot-unplugs three quarters of their memory? I think the kernel should protect itself against such foolishness.
