diff options
author | Zhang, Yanmin <yanmin.zhang@intel.com> | 2006-07-10 04:44:49 -0700 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-10 13:24:21 -0700 |
commit | b6174df5eec9cdfd598c03d6d0807e344e109213 (patch) | |
tree | d61c8627138a8feee31de8320e337251d567fca9 /include/asm-h8300/virtconvert.h | |
parent | d6b7d3b62069be60d5b13358bac8670dacdd7a81 (diff) |
[PATCH] mmap zero-length hugetlb file with PROT_NONE to protect a hugetlb virtual area
Sometimes, applications need below call to be successful although
"/mnt/hugepages/file1" doesn't exist.
fd = open("/mnt/hugepages/file1", O_CREAT|O_RDWR, 0755);
*addr = mmap(NULL, 0x1024*1024*256, PROT_NONE, 0, fd, 0);
As for regular pages (or files), above call does work, but as for huge
pages, above call would fail because hugetlbfs_file_mmap would fail if
(!(vma->vm_flags & VM_WRITE) && len > inode->i_size).
This capability on huge page is useful on ia64 when the process wants to
protect one area on region 4, so other threads couldn't read/write this
area. A famous JVM (Java Virtual Machine) implementation on IA64 needs the
capability.
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Hugh Dickins <hugh@veritas.com>
[ Expand-on-mmap semantics again... this time matching normal fs's. wli ]
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-h8300/virtconvert.h')
0 files changed, 0 insertions, 0 deletions