[PATCH, RFC 02/16] mm: implement zero_huge_user_segment and friends
From: Kirill A. Shutemov <hidden>
Date: 2013-01-28 09:24:14
Also in:
linux-fsdevel, lkml
Subsystem:
memory management, memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
From: "Kirill A. Shutemov" <redacted>
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 <redacted>
---
include/linux/mm.h | 15 +++++++++++++++
mm/memory.c | 22 ++++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e4533a1..c011771 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -1728,6 +1728,21 @@ 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 c04078b..200a74d 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -4185,6 +4185,28 @@ 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(); + + /* start and end are on the same small page */ + if ((start & PAGE_MASK) == (end & PAGE_MASK)) + return zero_user_segment(page + (start >> PAGE_SHIFT), + start & ~PAGE_MASK, end & ~PAGE_MASK); + + 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 & ~PAGE_MASK); +} + 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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