2018-07-10 18:50 GMT+09:00 Michal Hocko <mhocko@xxxxxxxxxx>: > On Tue 10-07-18 16:19:32, Joonsoo Kim wrote: >> Hello, Marek. >> >> 2018-07-09 21:19 GMT+09:00 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>: >> > cma_alloc() function doesn't really support gfp flags other than >> > __GFP_NOWARN, so convert gfp_mask parameter to boolean no_warn parameter. >> >> Although gfp_mask isn't used in cma_alloc() except no_warn, it can be used >> in alloc_contig_range(). For example, if passed gfp mask has no __GFP_FS, >> compaction(isolation) would work differently. Do you have considered >> such a case? > > Does any of cma_alloc users actually care about GFP_NO{FS,IO}? I don't know. My guess is that cma_alloc() is used for DMA allocation so block device would use it, too. If fs/block subsystem initiates the request for the device, it would be possible that cma_alloc() is called with such a flag. Again, I don't know much about those subsystem so I would be wrong. Thanks.