On Tue, 24 Apr 2018, Michal Hocko wrote: > On Wed 25-04-18 00:18:40, Richard Weinberger wrote: > > Am Dienstag, 24. April 2018, 21:28:03 CEST schrieb Michal Hocko: > > > > Also only for debugging. > > > > Getting rid of vmalloc with GFP_NOFS in UBIFS is no big problem. > > > > I can prepare a patch. > > > > > > Cool! > > > > > > Anyway, if UBIFS has some reclaim recursion critical sections in general > > > it would be really great to have them documented and that is where the > > > scope api is really handy. Just add the scope and document what is the > > > recursion issue. This will help people reading the code as well. Ideally > > > there shouldn't be any explicit GFP_NOFS in the code. > > > > So in a perfect world a filesystem calls memalloc_nofs_save/restore and > > always uses GFP_KERNEL for kmalloc/vmalloc? > > Exactly! And in a dream world those memalloc_nofs_save act as a > documentation of the reclaim recursion documentation ;) > -- > Michal Hocko > SUSE Labs BTW. should memalloc_nofs_save and memalloc_noio_save be merged into just one that prevents both I/O and FS recursion? memalloc_nofs_save allows submitting bios to I/O stack and the bios created under memalloc_nofs_save could be sent to the loop device and the loop device calls the filesystem... Mikulas
