[PATCH] remove VM_DONTCOPY bogosities

[Hugh Dickins]

Now that it's madvisable, remove two pieces of VM_DONTCOPY bogosity:

1. There was and is no logical reason why VM_DONTCOPY should be in the
   list of flags which forbid vma merging (and those drivers which set
   it are also setting VM_IO, which itself forbids the merge).

2. It's hard to understand the purpose of the VM_HUGETLB, VM_DONTCOPY
   block in vm_stat_account: but never mind, it's under CONFIG_HUGETLB,
   which (unlike CONFIG_HUGETLB_PAGE or CONFIG_HUGETLBFS) has never been
   defined.

Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>

---
Looks like wli is offline at present: I had been hoping to hear from him
before removing that block from vm_stat_account; but now that it turns
out never to have done anything anyway, let's go ahead and remove it.

 mm/mmap.c |   10 +---------
 1 files changed, 1 insertion(+), 9 deletions(-)

--- 2.6.16-rc3-git4/mm/mmap.c	2006-02-13 09:38:13.000000000 +0000
+++ linux/mm/mmap.c	2006-02-15 12:42:07.000000000 +0000
@@ -612,7 +612,7 @@ again:			remove_next = 1 + (end > next->
  * 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.
  */
-#define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
+#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
 
 static inline int is_mergeable_vma(struct vm_area_struct *vma,
 			struct file *file, unsigned long vm_flags)
@@ -845,14 +845,6 @@ void vm_stat_account(struct mm_struct *m
 	const unsigned long stack_flags
 		= VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
 
-#ifdef CONFIG_HUGETLB
-	if (flags & VM_HUGETLB) {
-		if (!(flags & VM_DONTCOPY))
-			mm->shared_vm += pages;
-		return;
-	}
-#endif /* CONFIG_HUGETLB */
-
 	if (file) {
 		mm->shared_vm += pages;
 		if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
-
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