Messages in this thread | | | From | "Chen, Kenneth W" <> | Subject | RE: hugepage: Fix hugepage logic in free_pgtables() | Date | Thu, 2 Mar 2006 13:29:50 -0800 |
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Hugh Dickins wrote on Thursday, March 02, 2006 12:27 PM > But the first part, || instead of && in is_hugepage_only_range, looks > insufficient: the start and end of the range might each fall in a > non-huge region, but the range still cross a huge region. > > Ah, does RGN_HPAGE nestle up against the TASK_SIZE roof, so any range > already tested against TASK_SIZE (as get_unmapped_area has) cannot > cross RGN_HPAGE? If so, perhaps it deserves a comment there. And > if that is so, and can be relied upon, is_hugepage_only_range need > only be testing REGION_NUMBER(addr+len-1) - but it does seem fragile.
There are many address range check before we hit get_unmapped area. ia64 can never have a vma range that crosses region boundary. David pointed out earlier that shmat and mremap can still slip through the crack and he has a patch that fixed it. But yes, this patch is making that assumption (or relying on checks being done properly beforehand).
- Ken
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