On 09/11/14 at 10:04am, Atsushi Kumagai wrote: > >On 09/11/14 at 08:52am, Atsushi Kumagai wrote: > >> >Hi Atsushi, > >> > > >> >Since huge pages are included in user pages, I can't think of a way to > >> >make test cases for huge page exclusion. Could you give some suggestions > >> >on this or how did you test it? > >> > >> Before I posted this patch, I tested as below. > >> This idea came from the fact that old makedumpfile can't exclude > >> huge pages except the first page(PG_head). > >> > >> 1. Get the number of hugepages from /proc/meminfo > >> 2. Calculate the number of PG_tail pages > >> 3. Capture the dumpfile without filtering > >> 4. Run makedumpfile and compare the report message between v1.5.6 > >> and v1.5.7(rc) to get how many user pages become excludable with > >> this patch. > >> 5. The result of Step2's and Step4's must be same, confirm it. > >> > >> The way above is for THP but you can apply it also for hugetlbfs > >> if you take care of the things that old makedumpfile can't exclude > >> *any* hugetlbfs pages. > > > >But THP is also Anonymous pages, doesn't it do the same for THP between > >1.5.6 and 1.5.7? > > Only a PG_head page is marked as an anonymous page, makedumpfile doesn't > distinguish PG_tail pages as anonymous pages. Please see below. > > do_huge_pmd_anonymous_page() > + __do_huge_pmd_anonymous_page() > + page_add_new_anon_rmap() > + __page_set_anon_rmap() Yes, you are right. Thanks, Atsushi!
