Commit f8dbf0a7 authored Sep 21, 2009 by Huang Shijie Committed by Linus Torvalds Sep 22, 2009

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>

parent 252c5f94

mm/mmap.c

+9 −9

Original line number	Diff line number	Diff line
		@@ -1191,11 +1191,6 @@ munmap_back:
		goto unmap_and_free_vma;
		if (vm_flags & VM_EXECUTABLE)
		added_exe_file_vma(mm);
		} else if (vm_flags & VM_SHARED) {
		error = shmem_zero_setup(vma);
		if (error)
		goto free_vma;
		}

		/* Can addr have changed??
		*
		@@ -1205,6 +1200,11 @@ munmap_back:
		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;
		}

		if (vma_wants_writenotify(vma))
		vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);

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