Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Thu, 2 Apr 2015 15:50:15 -0700 (PDT) | From | David Rientjes <> | Subject | [patch -mm] mm, doc: cleanup and clarify munmap behavior for hugetlb memory fix |
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Don't only specify munmap(2) behavior with respect the hugetlb memory, all other syscalls get naturally aligned to the native page size of the processor. Rather, pick out munmap(2) as a specific example.
Signed-off-by: David Rientjes <rientjes@google.com> --- Documentation/vm/hugetlbpage.txt | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/Documentation/vm/hugetlbpage.txt b/Documentation/vm/hugetlbpage.txt index 1270fb1..030977f 100644 --- a/Documentation/vm/hugetlbpage.txt +++ b/Documentation/vm/hugetlbpage.txt @@ -313,8 +313,11 @@ into /proc/sys/vm/hugetlb_shm_group. It is possible for same or different applications to use any combination of mmaps and shm* calls, though the mount of filesystem will be required for using mmap calls without MAP_HUGETLB. -When using munmap(2) to unmap hugetlb memory, the length specified must be -hugepage aligned, otherwise it will fail with errno set to EINVAL. +Syscalls that operate on memory backed by hugetlb pages only have their lengths +aligned to the native page size of the processor; they will normally fail with +errno set to EINVAL or exclude hugetlb pages that extend beyond the length if +not hugepage aligned. For example, munmap(2) will fail if memory is backed by +a hugetlb page and the length is smaller than the hugepage size. Examples
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