On Mon 24-06-19 12:43:26, zhong jiang wrote: > Recently, I hit an frequent oom issue in linux-4.4 stable with less than 4M free memory after > the machine boots up. Is this is a regression? Could you share the oom report? > 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. How get your get such a large fragmentation that you cannot allocate order-1 pages and compaction is not making any progress? > 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. Well, any reservation is a finite resource so I am not sure how that can help universally. But your description is quite vague. Could you be more specific about that workload? Also do you see the same with the current upstream kernel as well? -- Michal Hocko SUSE Labs
