From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Let's add helpers to clear huge page segment(s). They provide the same
functionallity as zero_user_segment{,s} and zero_user, but for huge
pages.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
include/linux/mm.h | 15 +++++++++++++++
mm/memory.c | 26 ++++++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5b7fd4e..df83ab9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1731,6 +1731,21 @@ extern void dump_page(struct page *page);
extern void clear_huge_page(struct page *page,
unsigned long addr,
unsigned int pages_per_huge_page);
+extern void zero_huge_user_segment(struct page *page,
+ unsigned start, unsigned end);
+static inline void zero_huge_user_segments(struct page *page,
+ unsigned start1, unsigned end1,
+ unsigned start2, unsigned end2)
+{
+ zero_huge_user_segment(page, start1, end1);
+ zero_huge_user_segment(page, start2, end2);
+}
+static inline void zero_huge_user(struct page *page,
+ unsigned start, unsigned len)
+{
+ zero_huge_user_segment(page, start, start+len);
+}
+
extern void copy_user_huge_page(struct page *dst, struct page *src,
unsigned long addr, struct vm_area_struct *vma,
unsigned int pages_per_huge_page);
diff --git a/mm/memory.c b/mm/memory.c
index 494526a..98c25dd 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4213,6 +4213,32 @@ void clear_huge_page(struct page *page,
}
}
+void zero_huge_user_segment(struct page *page, unsigned start, unsigned end)
+{
+ int i;
+
+ BUG_ON(end < start);
+
+ might_sleep();
+
+ if (start == end)
+ return;
+
+ /* start and end are on the same small page */
+ if ((start & PAGE_MASK) == ((end - 1) & PAGE_MASK))
+ return zero_user_segment(page + (start >> PAGE_SHIFT),
+ start & ~PAGE_MASK,
+ ((end - 1) & ~PAGE_MASK) + 1);
+
+ zero_user_segment(page + (start >> PAGE_SHIFT),
+ start & ~PAGE_MASK, PAGE_SIZE);
+ for (i = (start >> PAGE_SHIFT) + 1; i < (end >> PAGE_SHIFT) - 1; i++) {
+ cond_resched();
+ clear_highpage(page + i);
+ }
+ zero_user_segment(page + i, 0, ((end - 1) & ~PAGE_MASK) + 1);
+}
+
static void copy_user_gigantic_page(struct page *dst, struct page *src,
unsigned long addr,
struct vm_area_struct *vma,
--
1.7.10.4
--
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