thp: madvise(MADV_HUGEPAGE)
Add madvise MADV_HUGEPAGE to mark regions that are important to be
hugepage backed. Return -EINVAL if the vma is not of an anonymous type,
or the feature isn't built into the kernel. Never silently return
success.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 7635079..620891f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -896,6 +896,22 @@
return ret;
}
+int hugepage_madvise(unsigned long *vm_flags)
+{
+ /*
+ * Be somewhat over-protective like KSM for now!
+ */
+ if (*vm_flags & (VM_HUGEPAGE | VM_SHARED | VM_MAYSHARE |
+ VM_PFNMAP | VM_IO | VM_DONTEXPAND |
+ VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |
+ VM_MIXEDMAP | VM_SAO))
+ return -EINVAL;
+
+ *vm_flags |= VM_HUGEPAGE;
+
+ return 0;
+}
+
void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd)
{
struct page *page;