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| author | Huang Shijie <shijie8@gmail.com> | 2009-09-21 17:03:41 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:41 -0700 |
| commit | f8dbf0a7a4c5d98e8b70da9f7f4f6a89f3b7a7bb (patch) | |
| tree | 1f40d51f39965017999c36e3a5ae78b67e43f5d5 /mm/mmap.c | |
| parent | 252c5f94d944487e9f50ece7942b0fbf659c5c31 (diff) | |
| download | lwn-f8dbf0a7a4c5d98e8b70da9f7f4f6a89f3b7a7bb.tar.gz lwn-f8dbf0a7a4c5d98e8b70da9f7f4f6a89f3b7a7bb.zip | |
mmap: save some cycles for the shared anonymous mapping
shmem_zero_setup() does not change vm_start, pgoff or vm_flags, only some
drivers change them (such as /driver/video/bfin-t350mcqb-fb.c).
Move these codes to a more proper place to save cycles for shared
anonymous mapping.
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index b6d74b3dbbc2..1aeef6625e6a 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1191,21 +1191,21 @@ munmap_back: goto unmap_and_free_vma; if (vm_flags & VM_EXECUTABLE) added_exe_file_vma(mm); + + /* Can addr have changed?? + * + * Answer: Yes, several device drivers can do it in their + * f_op->mmap method. -DaveM + */ + addr = vma->vm_start; + pgoff = vma->vm_pgoff; + vm_flags = vma->vm_flags; } else if (vm_flags & VM_SHARED) { error = shmem_zero_setup(vma); if (error) goto free_vma; } - /* Can addr have changed?? - * - * Answer: Yes, several device drivers can do it in their - * f_op->mmap method. -DaveM - */ - addr = vma->vm_start; - pgoff = vma->vm_pgoff; - vm_flags = vma->vm_flags; - if (vma_wants_writenotify(vma)) vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); |