[PATCH] remove VM_DONTCOPY bogosities (a6f563db) · Commits · 戴 / test

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@veritas.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

mm/mmap.c

+1 −9

Original line number	Diff line number	Diff line
		@@ -612,7 +612,7 @@ again: remove_next = 1 + (end > next->vm_end);
		* 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 *mm, unsigned long flags,
		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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