On 2016/6/20 14:48, Joonsoo Kim wrote: > On Fri, Jun 17, 2016 at 03:38:49PM +0800, Chen Feng wrote: >> Hi Kim & feng, >> >> Thanks for the share. In our platform also has the same use case. >> >> We only let the alloc with GFP_HIGHUSER_MOVABLE in memory.c to use cma >> memory. >> >> If we add zone_cma, It seems can resolve the cma migrate issue. >> >> But when free_hot_cold_page, we need let the cma page goto system directly >> not the pcp. >> It can be fail while cma_alloc and cma_release. If we alloc the whole cma >> pages which >> declared before. > > Hmm...I'm not sure I understand your explanation. So, if I miss > something, please let me know. We calls drain_all_pages() when > isolating pageblock and alloc_contig_range() also has one > drain_all_pages() calls to drain pcp pages. And, after pageblock isolation, > freed pages belonging to MIGRATE_ISOLATE pageblock will go to the > buddy directly so there would be no problem you mentioned. Isn't it? > Yes, you are right.
I mean if the we free cma page to pcp-list, it will goto the migrate_movable list. Then the alloc with movable flag can use the cma memory from the list with buffered_rmqueue. But that's not what we want. It will cause the migrate fail if all movable alloc can use cma memory. If I am wrong, please correct me. Thanks. > Thanks. > > . >
