On Thu 08-12-16 17:36:24, Huang Shijie wrote: > On Wed, Dec 07, 2016 at 11:02:38PM +0800, Michal Hocko wrote: [...] > > I haven't yet checked your patchset but I can tell you one thing. > > Could you please review the patch set when you have time? Thanks a lot. >From a quick glance you do not handle the reservation code at all. You just make sure that the allocation doesn't fail unconditionally. I might be wrong here and Naoya resp. Mike will know much better but this seems far from enough to me. > > > Surplus and subpool pages code is tricky as hell. And it is not just a > Agree. > > Do we really need so many accountings? such as reserve/ovorcommit/surplus. If we want to make giga page the first class citizen then the whole reservation/surplus code has to independent on the page size. > > matter of teaching the huge page allocation code to do the right thing. > > There are subtle details all over the place. E.g. we currently > > do not free giga pages AFAICS. In fact I believe that the giga pages are > Please correct me if I am wrong. :) > > I think the free-giga-pages can work well. > Please see the code in update_and_free_page(). Hmm, I have missed that part. I guess you are right but I would have to look much closer. Hugetlb code tends to be full of surprises. > Could you please list all the subtle details you think the code is wrong? > I can check them one by one. Well, this would take me quite some time and basically restudy the whole hugetlb code again. What you are trying to achieve is not a simple "fix a test case" thing. You are trying to implement full featured giga pages suport. And as I've said this requires a deeper understanding of the current code and clean it up considerably wrt. giga pages. This is definitely desirable plan longterm and I would like to encourage you for that but it is not a simple project at the same time. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>