On Mon 02-07-18 15:23:34, Marek Szyprowski wrote: > Hi Michal, > > On 2018-06-13 15:39, Michal Hocko wrote: > > On Wed 13-06-18 05:55:46, Christoph Hellwig wrote: > >> On Wed, Jun 13, 2018 at 02:40:00PM +0200, Marek Szyprowski wrote: > >>> It is not only the matter of the spinlocks. GFP_ATOMIC is not supported > >>> by the > >>> memory compaction code, which is used in alloc_contig_range(). Right, this > >>> should be also noted in the documentation. > >> Documentation is good, asserts are better. The code should reject any > >> flag not explicitly supported, or even better have its own flags type > >> with the few actually supported flags. > > Agreed. Is the cma allocator used for anything other than GFP_KERNEL > > btw.? If not then, shouldn't we simply drop the gfp argument altogether > > rather than give users a false hope for differen gfp modes that are not > > really supported and grow broken code? > > Nope, all cma_alloc() callers are expected to use it with GFP_KERNEL gfp > mask. > The only flag which is now checked is __GFP_NOWARN. I can change the > function > signature of cma_alloc to: > struct page *cma_alloc(struct cma *cma, size_t count, unsigned int > align, bool no_warn); Are there any __GFP_NOWARN users? I have quickly hit the indirection trap and searching for alloc callback didn't tell me really much. > What about clearing the allocated buffer? Should it be another bool > parameter, done unconditionally or moved to the callers? That really depends on callers. I have no idea what they actually ask for. -- Michal Hocko SUSE Labs
