Messages in this thread |  | | | Date | Wed, 9 Nov 2005 16:15:34 -0800 | | From | William Lee Irwin III <> | | Subject | Re: [PATCH 4/4] Hugetlb: Copy on Write support |
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On Wed, Nov 09, 2005 at 05:39:55PM -0600, Adam Litke wrote: > Hugetlb: Copy on Write support > Implement copy-on-write support for hugetlb mappings so MAP_PRIVATE can be > supported. This helps us to safely use hugetlb pages in many more > applications. The patch makes the following changes. If needed, I also have > it broken out according to the following paragraphs. > 1. Add a pair of functions to set/clear write access on huge ptes. The > writable check in make_huge_pte is moved out to the caller for use by COW > later. > 2. Hugetlb copy-on-write requires special case handling in the following > situations: > - copy_hugetlb_page_range() - Copied pages must be write protected so a COW > fault will be triggered (if necessary) if those pages are written to. > - find_or_alloc_huge_page() - Only MAP_SHARED pages are added to the page > cache. MAP_PRIVATE pages still need to be locked however. > 3. Provide hugetlb_cow() and calls from hugetlb_fault() and hugetlb_no_page() > which handles the COW fault by making the actual copy. > 4. Remove the check in hugetlbfs_file_map() so that MAP_PRIVATE mmaps will be > allowed. Make MAP_HUGETLB exempt from the depricated VM_RESERVED mapping > check.
Did you do the audit of pte protection bits I asked about? If not, I'll dredge them up and check to make sure.
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