On Sat, 21 Apr 2018, Vlastimil Babka wrote: > > The problem is that SLUB does not honor GFP_NORETRY. The semantics of > > GFP_NORETRY are not followed. > > The caller might want SLUB to try hard to get that high-order page that > will minimize memory waste (e.g. 2MB page for 3 640k objects), and > __GFP_NORETRY will kill the effort on allocating that high-order page. Well yes since *_NORETRY says that fallbacks are acceptable. > Thus, using __GPF_NORETRY for "please give me a space-optimized object, > or nothing (because I have a fallback that's better than wasting memory, > e.g. by using 1MB page for 640kb object)" is not ideal. > > Maybe __GFP_RETRY_MAYFAIL is a better fit? Or perhaps indicate this > situation to SLUB with e.g. __GFP_COMP, although that's rather ugly? Yuck. None of that sounds like an intuitive approach.
