Recently, I hit an frequent oom issue in linux-4.4 stable with less than 4M free memory after the machine boots up. As the process is created, kernel stack will use the higher order to allocate continuous memory. Due to the fragmentabtion, we fails to allocate the memory. And the low memory will result in hardly memory compction. hence, it will easily to reproduce the oom. But if we use migrate_reserve to reserve at least a pageblock at the boot stage. we can use the reserve memory to allocate continuous memory for process when the system is under severerly fragmentation. In my opinion, Reserve memory will relieve the pressure effectively at least in small memroy machine. Any ideas? Thanks
