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From:   Zi Yan <zi.yan@sent.com>
To:     Dave Hansen <dave.hansen@linux.intel.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Keith Busch <keith.busch@intel.com>,
        Fengguang Wu <fengguang.wu@intel.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Cc:     Daniel Jordan <daniel.m.jordan@oracle.com>,
        Michal Hocko <mhocko@kernel.org>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>,
        John Hubbard <jhubbard@nvidia.com>,
        Mark Hairgrove <mhairgrove@nvidia.com>,
        Nitin Gupta <nigupta@nvidia.com>,
        Javier Cabezas <jcabezas@nvidia.com>,
        David Nellans <dnellans@nvidia.com>, Zi Yan <ziy@nvidia.com>
Subject: [RFC PATCH 02/25] mm: migrate: Add mode parameter to support future page copy routines.
Date:   Wed,  3 Apr 2019 19:00:23 -0700
Message-Id: <20190404020046.32741-3-zi.yan@sent.com>
In-Reply-To: <20190404020046.32741-1-zi.yan@sent.com>
References: <20190404020046.32741-1-zi.yan@sent.com>
Reply-To: ziy@nvidia.com
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From: Zi Yan <ziy@nvidia.com>

MIGRATE_SINGLETHREAD is added as the default behavior.
migrate_page_copy() and copy_huge_page() are changed.

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
 fs/aio.c                     |  2 +-
 fs/f2fs/data.c               |  2 +-
 fs/hugetlbfs/inode.c         |  2 +-
 fs/iomap.c                   |  2 +-
 fs/ubifs/file.c              |  2 +-
 include/linux/migrate.h      |  6 ++++--
 include/linux/migrate_mode.h |  3 +++
 mm/migrate.c                 | 14 ++++++++------
 8 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 0a88dfd..986d21e 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -437,7 +437,7 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 	 * events from being lost.
 	 */
 	spin_lock_irqsave(&ctx->completion_lock, flags);
-	migrate_page_copy(new, old);
+	migrate_page_copy(new, old, MIGRATE_SINGLETHREAD);
 	BUG_ON(ctx->ring_pages[idx] != old);
 	ctx->ring_pages[idx] = new;
 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index e7f0e3a..6a419a9 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2826,7 +2826,7 @@ int f2fs_migrate_page(struct address_space *mapping,
 	}
 
 	if ((mode & MIGRATE_MODE_MASK) != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		migrate_page_copy(newpage, page, MIGRATE_SINGLETHREAD);
 	else
 		migrate_page_states(newpage, page);
 
diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 04ba8bb..03dfa49 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -886,7 +886,7 @@ static int hugetlbfs_migrate_page(struct address_space *mapping,
 	}
 
 	if ((mode & MIGRATE_MODE_MASK) != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		migrate_page_copy(newpage, page, MIGRATE_SINGLETHREAD);
 	else
 		migrate_page_states(newpage, page);
 
diff --git a/fs/iomap.c b/fs/iomap.c
index 8ee3f9f..a6e0456 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -585,7 +585,7 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage,
 	}
 
 	if ((mode & MIGRATE_MODE_MASK) != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		migrate_page_copy(newpage, page, MIGRATE_SINGLETHREAD);
 	else
 		migrate_page_states(newpage, page);
 	return MIGRATEPAGE_SUCCESS;
diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c
index 2bb8788..3a3dbbd 100644
--- a/fs/ubifs/file.c
+++ b/fs/ubifs/file.c
@@ -1491,7 +1491,7 @@ static int ubifs_migrate_page(struct address_space *mapping,
 	}
 
 	if ((mode & MIGRATE_MODE_MASK) != MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		migrate_page_copy(newpage, page, MIGRATE_SINGLETHREAD);
 	else
 		migrate_page_states(newpage, page);
 	return MIGRATEPAGE_SUCCESS;
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index e13d9bf..5218a07 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -73,7 +73,8 @@ extern void putback_movable_page(struct page *page);
 extern int migrate_prep(void);
 extern int migrate_prep_local(void);
 extern void migrate_page_states(struct page *newpage, struct page *page);
-extern void migrate_page_copy(struct page *newpage, struct page *page);
+extern void migrate_page_copy(struct page *newpage, struct page *page,
+				  enum migrate_mode mode);
 extern int migrate_huge_page_move_mapping(struct address_space *mapping,
 				  struct page *newpage, struct page *page);
 extern int migrate_page_move_mapping(struct address_space *mapping,
@@ -97,7 +98,8 @@ static inline void migrate_page_states(struct page *newpage, struct page *page)
 }
 
 static inline void migrate_page_copy(struct page *newpage,
-				     struct page *page) {}
+				     struct page *page,
+				     enum migrate_mode mode) {}
 
 static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
 				  struct page *newpage, struct page *page)
diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h
index 59d75fc..da44940 100644
--- a/include/linux/migrate_mode.h
+++ b/include/linux/migrate_mode.h
@@ -11,6 +11,8 @@
  *	with the CPU. Instead, page copy happens outside the migratepage()
  *	callback and is likely using a DMA engine. See migrate_vma() and HMM
  *	(mm/hmm.c) for users of this mode.
+ * MIGRATE_SINGLETHREAD uses a single thread to move pages, it is the default
+ *	behavior
  */
 enum migrate_mode {
 	MIGRATE_ASYNC,
@@ -19,6 +21,7 @@ enum migrate_mode {
 	MIGRATE_SYNC_NO_COPY,
 
 	MIGRATE_MODE_MASK = 3,
+	MIGRATE_SINGLETHREAD	= 0,
 };
 
 #endif		/* MIGRATE_MODE_H_INCLUDED */
diff --git a/mm/migrate.c b/mm/migrate.c
index c161c03..2b2653e 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -567,7 +567,8 @@ static void __copy_gigantic_page(struct page *dst, struct page *src,
 	}
 }
 
-static void copy_huge_page(struct page *dst, struct page *src)
+static void copy_huge_page(struct page *dst, struct page *src,
+				enum migrate_mode mode)
 {
 	int i;
 	int nr_pages;
@@ -657,10 +658,11 @@ void migrate_page_states(struct page *newpage, struct page *page)
 }
 EXPORT_SYMBOL(migrate_page_states);
 
-void migrate_page_copy(struct page *newpage, struct page *page)
+void migrate_page_copy(struct page *newpage, struct page *page,
+		enum migrate_mode mode)
 {
 	if (PageHuge(page) || PageTransHuge(page))
-		copy_huge_page(newpage, page);
+		copy_huge_page(newpage, page, mode);
 	else
 		copy_highpage(newpage, page);
 
@@ -692,7 +694,7 @@ int migrate_page(struct address_space *mapping,
 		return rc;
 
 	if ((mode & MIGRATE_MODE_MASK) !=  MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		migrate_page_copy(newpage, page, mode);
 	else
 		migrate_page_states(newpage, page);
 	return MIGRATEPAGE_SUCCESS;
@@ -805,7 +807,7 @@ static int __buffer_migrate_page(struct address_space *mapping,
 	SetPagePrivate(newpage);
 
 	if ((mode & MIGRATE_MODE_MASK) !=  MIGRATE_SYNC_NO_COPY)
-		migrate_page_copy(newpage, page);
+		migrate_page_copy(newpage, page, MIGRATE_SINGLETHREAD);
 	else
 		migrate_page_states(newpage, page);
 
@@ -2024,7 +2026,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 	new_page->index = page->index;
 	/* flush the cache before copying using the kernel virtual address */
 	flush_cache_range(vma, start, start + HPAGE_PMD_SIZE);
-	migrate_page_copy(new_page, page);
+	migrate_page_copy(new_page, page, MIGRATE_SINGLETHREAD);
 	WARN_ON(PageLRU(new_page));
 
 	/* Recheck the target PMD */
-- 
2.7.4