On 2016/11/7 15:44, Chen Feng wrote: > On 2016/11/7 15:27, Joonsoo Kim wrote: >> On Mon, Nov 07, 2016 at 03:08:49PM +0800, Chen Feng wrote: >>> >>> >>> On 2016/11/7 14:15, Joonsoo Kim wrote: >>>> On Tue, Nov 01, 2016 at 03:58:32PM +0800, Chen Feng wrote: >>>>> Hello, I hava a question on cma zone. >>>>> >>>>> When we have cma zone, cma zone will be the highest zone of system. >>>>> >>>>> In android system, the most memory allocator is ION. Media system will >>>>> alloc unmovable memory from it. >>>>> >>>>> On low memory scene, will the CMA zone always do balance? >>>> >>>> Allocation request for low zone (normal zone) would not cause CMA zone >>>> to be balanced since it isn't helpful. >>>> >>> Yes. But the cma zone will run out soon. And it always need to do balance. >>> >>> How about use migrate cma before movable and let cma type to fallback movable. >>> >>> https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1263745.html >> >> ZONE_CMA approach will act like as your solution. Could you elaborate >> more on the problem of zone approach? >> > > The ZONE approach is that makes cma pages in a zone. It can cause a higher swapin/out > than use migrate cma first. > > The higher swapin/out may have a performance effect to application. The application may > use too much time swapin memory. > > You can see my tested result attached for detail. And the baseline is result of [1]. > > My test case is run 60 applications and alloc 512MB ION memory. Repeat this action 50 times > [1] https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1263745.html >> 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>