[PATCH 02/10] migrate: make core migration code aware of hugepage

[Naoya Horiguchi]

Before enabling each user of page migration to support hugepage,
this patch adds necessary changes on core migration code.
The main change is that the list of pages to migrate can link
not only LRU pages, but also hugepages.
Along with this, functions such as migrate_pages() and
putback_movable_pages() need to be changed to handle hugepages.

ChangeLog v2:
 - move code removing VM_HUGETLB from vma_migratable check into a
   separate patch
 - hold hugetlb_lock in putback_active_hugepage
 - update comment near the definition of hugetlb_lock

Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
 include/linux/hugetlb.h |  4 ++++
 include/linux/migrate.h |  6 ++++++
 mm/hugetlb.c            | 21 ++++++++++++++++++++-
 mm/migrate.c            | 24 +++++++++++++++++++++++-
 4 files changed, 53 insertions(+), 2 deletions(-)

diff --git v3.9-rc3.orig/include/linux/hugetlb.h v3.9-rc3/include/linux/hugetlb.h
index 16e4e9a..baa0aa0 100644
--- v3.9-rc3.orig/include/linux/hugetlb.h
+++ v3.9-rc3/include/linux/hugetlb.h
@@ -66,6 +66,8 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to,
 						vm_flags_t vm_flags);
 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed);
 int dequeue_hwpoisoned_huge_page(struct page *page);
+void putback_active_hugepage(struct page *page);
+void putback_active_hugepages(struct list_head *l);
 void copy_huge_page(struct page *dst, struct page *src);
 
 extern unsigned long hugepages_treat_as_movable;
@@ -128,6 +130,8 @@ static inline int dequeue_hwpoisoned_huge_page(struct page *page)
 	return 0;
 }
 
+#define putback_active_hugepage(p) 0
+#define putback_active_hugepages(l) 0
 static inline void copy_huge_page(struct page *dst, struct page *src)
 {
 }
diff --git v3.9-rc3.orig/include/linux/migrate.h v3.9-rc3/include/linux/migrate.h
index a405d3dc..d4c6c08 100644
--- v3.9-rc3.orig/include/linux/migrate.h
+++ v3.9-rc3/include/linux/migrate.h
@@ -41,6 +41,9 @@ extern int migrate_page(struct address_space *,
 			struct page *, struct page *, enum migrate_mode);
 extern int migrate_pages(struct list_head *l, new_page_t x,
 		unsigned long private, enum migrate_mode mode, int reason);
+extern int migrate_movable_pages(struct list_head *from,
+		new_page_t get_new_page, unsigned long private,
+		enum migrate_mode mode, int reason);
 extern int migrate_huge_page(struct page *, new_page_t x,
 		unsigned long private, enum migrate_mode mode);
 
@@ -62,6 +65,9 @@ static inline void putback_movable_pages(struct list_head *l) {}
 static inline int migrate_pages(struct list_head *l, new_page_t x,
 		unsigned long private, enum migrate_mode mode, int reason)
 	{ return -ENOSYS; }
+static inline int migrate_movable_pages(struct list_head *from,
+		new_page_t get_new_page, unsigned long private, bool offlining,
+		enum migrate_mode mode, int reason) { return -ENOSYS; }
 static inline int migrate_huge_page(struct page *page, new_page_t x,
 		unsigned long private, enum migrate_mode mode)
 	{ return -ENOSYS; }
diff --git v3.9-rc3.orig/mm/hugetlb.c v3.9-rc3/mm/hugetlb.c
index 98a478e..a787c44 100644
--- v3.9-rc3.orig/mm/hugetlb.c
+++ v3.9-rc3/mm/hugetlb.c
@@ -48,7 +48,8 @@ static unsigned long __initdata default_hstate_max_huge_pages;
 static unsigned long __initdata default_hstate_size;
 
 /*
- * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
+ * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
+ * free_huge_pages, and surplus_huge_pages.
  */
 DEFINE_SPINLOCK(hugetlb_lock);
 
@@ -3182,3 +3183,21 @@ int dequeue_hwpoisoned_huge_page(struct page *hpage)
 	return ret;
 }
 #endif
+
+void putback_active_hugepage(struct page *page)
+{
+	VM_BUG_ON(!PageHead(page));
+	spin_lock(&hugetlb_lock);
+	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
+	spin_unlock(&hugetlb_lock);
+	put_page(page);
+}
+
+void putback_active_hugepages(struct list_head *l)
+{
+	struct page *page;
+	struct page *page2;
+
+	list_for_each_entry_safe(page, page2, l, lru)
+		putback_active_hugepage(page);
+}
diff --git v3.9-rc3.orig/mm/migrate.c v3.9-rc3/mm/migrate.c
index ec692a3..f69f354 100644
--- v3.9-rc3.orig/mm/migrate.c
+++ v3.9-rc3/mm/migrate.c
@@ -100,6 +100,10 @@ void putback_movable_pages(struct list_head *l)
 	struct page *page2;
 
 	list_for_each_entry_safe(page, page2, l, lru) {
+		if (unlikely(PageHuge(page))) {
+			putback_active_hugepage(page);
+			continue;
+		}
 		list_del(&page->lru);
 		dec_zone_page_state(page, NR_ISOLATED_ANON +
 				page_is_file_cache(page));
@@ -1023,7 +1027,11 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
 		list_for_each_entry_safe(page, page2, from, lru) {
 			cond_resched();
 
-			rc = unmap_and_move(get_new_page, private,
+			if (PageHuge(page))
+				rc = unmap_and_move_huge_page(get_new_page,
+						private, page, pass > 2, mode);
+			else
+				rc = unmap_and_move(get_new_page, private,
 						page, pass > 2, mode);
 
 			switch(rc) {
@@ -1056,6 +1064,20 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
 	return rc;
 }
 
+int migrate_movable_pages(struct list_head *from, new_page_t get_new_page,
+			unsigned long private,
+			enum migrate_mode mode, int reason)
+{
+	int err = 0;
+
+	if (!list_empty(from)) {
+		err = migrate_pages(from, get_new_page, private, mode, reason);
+		if (err)
+			putback_movable_pages(from);
+	}
+	return err;
+}
+
 int migrate_huge_page(struct page *hpage, new_page_t get_new_page,
 		      unsigned long private, enum migrate_mode mode)
 {
-- 
1.7.11.7

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/