Hello experts, 

I find admin_reserve_kbytes is not working as documented since 
commit 8c7829b04c523cdc(mm: fix false-positive OVERCOMMIT_GUESS failures). 

Before that, available free pages are used to determine the allocation check, and admin_reserve_kbytes 
was honored in the default GUESS over_commit mode. While after that commit, admin_reserve_kbytes 
is not honored in default mode any more. This looks like break the sysctl usage? 

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

admin_reserve_kbytes 
==================== 

The amount of free memory in the system that should be reserved for users 
with the capability cap_sys_admin. 

admin_reserve_kbytes defaults to min(3% of free pages, 8MB) 

That should provide enough for the admin to log in and kill a process, 
if necessary, under the default overcommit 'guess' mode. 

....... 


-- 
Regards, 
Chunyu Hu