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author | David Gibson <david@gibson.dropbear.id.au> | 2006-01-06 09:10:44 +0100 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-06 17:33:23 +0100 |
commit | 1e8f889b10d8d2223105719e36ce45688fedbd59 (patch) | |
tree | 86dee89e4363aaf6c7ec7c9751ea37f725c95bb9 /fs/hugetlbfs | |
parent | [PATCH] Hugetlb: Reorganize hugetlb_fault to prepare for COW (diff) | |
download | linux-1e8f889b10d8d2223105719e36ce45688fedbd59.tar.xz linux-1e8f889b10d8d2223105719e36ce45688fedbd59.zip |
[PATCH] 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.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "Seth, Rohit" <rohit.seth@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/hugetlbfs')
-rw-r--r-- | fs/hugetlbfs/inode.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 8c1cef3bb677..8c41315a6e42 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -100,9 +100,6 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma) loff_t len, vma_len; int ret; - if ((vma->vm_flags & (VM_MAYSHARE | VM_WRITE)) == VM_WRITE) - return -EINVAL; - if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1)) return -EINVAL; |