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| author |   Hugh Dickins <hugh.dickins@tiscali.co.uk> | 2009-09-21 17:02:25 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:33 -0700 |
| commit | 8314c4f24a0a5c9b1f7544e9fa83a1d5367ddaa7 (patch) | |
| tree | f3265e2ff817e447c11b9f9070ce1eed9a19731a /mm | |
| parent | ksm: add some documentation (diff) | |
| download | linux-dev-8314c4f24a0a5c9b1f7544e9fa83a1d5367ddaa7.tar.xz linux-dev-8314c4f24a0a5c9b1f7544e9fa83a1d5367ddaa7.zip | |
ksm: remove VM_MERGEABLE_FLAGS
KSM originally stood for Kernel Shared Memory: but the kernel has long
supported shared memory, and VM_SHARED and VM_MAYSHARE vmas, and KSM is
something else. So we switched to saying "merge" instead of "share".
But Chris Wright points out that this is confusing where mmap.c merges
adjacent vmas: most especially in the name VM_MERGEABLE_FLAGS, used by
is_mergeable_vma() to let vmas be merged despite flags being different.
Call it VMA_MERGE_DESPITE_FLAGS? Perhaps, but at present it consists
only of VM_CAN_NONLINEAR: so for now it's clearer on all sides to use
that directly, with a comment on it in is_mergeable_vma().
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mmap.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index ffd6c6c9bcf4..22dff49d579e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -657,9 +657,6 @@ again: remove_next = 1 + (end > next->vm_end); validate_mm(mm); } -/* Flags that can be inherited from an existing mapping when merging */ -#define VM_MERGEABLE_FLAGS (VM_CAN_NONLINEAR) - /* * If the vma has a ->close operation then the driver probably needs to release * per-vma resources, so we don't attempt to merge those. @@ -667,7 +664,8 @@ again: remove_next = 1 + (end > next->vm_end); static inline int is_mergeable_vma(struct vm_area_struct *vma, struct file *file, unsigned long vm_flags) { - if ((vma->vm_flags ^ vm_flags) & ~VM_MERGEABLE_FLAGS) + /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */ + if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR) return 0; if (vma->vm_file != file) return 0; |