On Thu, Oct 16, 2014 at 11:35:47AM +0800, Hui Zhu wrote: > In fallbacks of page_alloc.c, MIGRATE_CMA is the fallback of > MIGRATE_MOVABLE. > MIGRATE_MOVABLE will use MIGRATE_CMA when it doesn't have a page in > order that Linux kernel want. > > If a system that has a lot of user space program is running, for > instance, an Android board, most of memory is in MIGRATE_MOVABLE and > allocated. Before function __rmqueue_fallback get memory from > MIGRATE_CMA, the oom_killer will kill a task to release memory when > kernel want get MIGRATE_UNMOVABLE memory because fallbacks of > MIGRATE_UNMOVABLE are MIGRATE_RECLAIMABLE and MIGRATE_MOVABLE. > This status is odd. The MIGRATE_CMA has a lot free memory but Linux > kernel kill some tasks to release memory. > > This patch series adds a new function CMA_AGGRESSIVE to make CMA memory > be more aggressive about allocation. > If function CMA_AGGRESSIVE is available, when Linux kernel call function > __rmqueue try to get pages from MIGRATE_MOVABLE and conditions allow, > MIGRATE_CMA will be allocated as MIGRATE_MOVABLE first. If MIGRATE_CMA > doesn't have enough pages for allocation, go back to allocate memory from > MIGRATE_MOVABLE. > Then the memory of MIGRATE_MOVABLE can be kept for MIGRATE_UNMOVABLE and > MIGRATE_RECLAIMABLE which doesn't have fallback MIGRATE_CMA. Hello, I did some work similar to this. Please reference following links. https://lkml.org/lkml/2014/5/28/64 https://lkml.org/lkml/2014/5/28/57 And, aggressive allocation should be postponed until freepage counting bug is fixed, because aggressive allocation enlarge the possiblity of problem occurence. I tried to fix that bug, too. See following link. https://lkml.org/lkml/2014/10/23/90 Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>