Hi everyone, so I reviewed the ppc gup_fast hugetlbfs code a bit, fixed the longstanding memory corrupting bugs (could trigger if mmremap functions run under gup_fast) and I fixed the code that was supposed to make it work with thp introduction in 2.6.38 and more recently with the tail refcounting race fixes in -mm. This is incremental with the thp refcoutning race fixes merged in -mm. To me those rollbacking if the pte changed that ppc is doing looks unnecessary, the speculative access also looks unnecessary (there is no way the page_count of the head or regular pages can be zero there). x86 doesn't do any specualtive refcounting and it won't care if the pte changed (we know the page can't go away from under us because irqs are disabled). If tlb flushing code works on ppc like x86 there should be no need of that. However I didn't remove those two rollback conditions, in theory it shouldn't hurt (well not anymore, after fixing the two corrupting bugs...). I just tried to make the minimal changes required because I didn't test it. It'd be nice if ppc users could test it with O_DIRECT on top of hugetlbfs and report if this works. I build-tested it though, so it should build just fine at least. s390x should be the only other arch that needs revisiting to make gup_fast + hugetlbfs to work properly. I'll do that next. [PATCH 1/4] powerpc: remove superfluous PageTail checks on the pte gup_fast [PATCH 2/4] powerpc: get_hugepte() don't put_page() the wrong page [PATCH 3/4] powerpc: gup_hugepte() avoid to free the head page too many times [PATCH 4/4] powerpc: gup_hugepte() support THP based tail recounting -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>