On Tue 27-03-18 10:13:53, Goldwyn Rodrigues wrote: > > > On 03/27/2018 09:21 AM, Matthew Wilcox wrote: [...] > > Maybe no real filesystem behaves that way. We need feedback from > > filesystem people. > > The idea is to: > * Keep a central location for check, rather than individual filesystem > writepage(). It should reduce code as well. > * Filesystem developers call memory allocations without thinking twice > about which GFP flag to use: GFP_KERNEL or GFP_NOFS. In essence > eliminate GFP_NOFS. I do not think this is the right approach. We do want to eliminate explicit GFP_NOFS usage, but we also want to reduce the overal GFP_NOFS usage as well. The later requires that we drop the __GFP_FS only for those contexts that really might cause reclaim recursion problems. So in your example, it would be much better to add the scope into those writepage(s) implementations which actually can trigger the writeback from the reclaim path rather from the generic implementation which has no means to know that. -- Michal Hocko SUSE Labs
