From d5053ea0cfdcf2f4bc49d285f3cb5985c3d2a9bd Mon Sep 17 00:00:00 2001
From: Chao Yu <yuchao0@huawei.com>
Date: Wed, 27 Apr 2016 21:40:15 +0800
Subject: [PATCH] f2fs: move node pages only in victim section during GC

For foreground GC, we cache node blocks in victim section and set them
dirty, then we call sync_node_pages to flush these node pages, but
meanwhile, those node pages which does not locate in victim section
will be flushed together, so more bandwidth and continuous free space
would be occupied.

So for this condition, it's better to leave those unrelated node page
in cache for further write hit, and let CP or VM to flush them afterward.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h |  1 +
 fs/f2fs/gc.c   | 25 ++++---------------------
 fs/f2fs/node.c | 31 +++++++++++++++++++++++++++++++
 3 files changed, 36 insertions(+), 21 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index ca828b0e7d6d8..6a482411e6d47 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1783,6 +1783,7 @@ void ra_node_page(struct f2fs_sb_info *, nid_t);
 struct page *get_node_page(struct f2fs_sb_info *, pgoff_t);
 struct page *get_node_page_ra(struct page *, int);
 void sync_inode_page(struct dnode_of_data *);
+void move_node_page(struct page *, int);
 int fsync_node_pages(struct f2fs_sb_info *, nid_t, struct writeback_control *,
 								bool);
 int sync_node_pages(struct f2fs_sb_info *, struct writeback_control *);
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index e82046523186b..19e9fafc5c700 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -465,15 +465,7 @@ next_step:
 			continue;
 		}
 
-		/* set page dirty and write it */
-		if (gc_type == FG_GC) {
-			f2fs_wait_on_page_writeback(node_page, NODE, true);
-			set_page_dirty(node_page);
-		} else {
-			if (!PageWriteback(node_page))
-				set_page_dirty(node_page);
-		}
-		f2fs_put_page(node_page, 1);
+		move_node_page(node_page, gc_type);
 		stat_inc_node_blk_count(sbi, 1, gc_type);
 	}
 
@@ -834,18 +826,9 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
 		f2fs_put_page(sum_page, 0);
 	}
 
-	if (gc_type == FG_GC) {
-		if (type == SUM_TYPE_NODE) {
-			struct writeback_control wbc = {
-				.sync_mode = WB_SYNC_ALL,
-				.nr_to_write = LONG_MAX,
-				.for_reclaim = 0,
-			};
-			sync_node_pages(sbi, &wbc);
-		} else {
-			f2fs_submit_merged_bio(sbi, DATA, WRITE);
-		}
-	}
+	if (gc_type == FG_GC)
+		f2fs_submit_merged_bio(sbi,
+				(type == SUM_TYPE_NODE) ? NODE : DATA, WRITE);
 
 	blk_finish_plug(&plug);
 
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index de070a524fd2c..f80cfb6beac67 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1222,6 +1222,37 @@ iput_out:
 	iput(inode);
 }
 
+void move_node_page(struct page *node_page, int gc_type)
+{
+	if (gc_type == FG_GC) {
+		struct f2fs_sb_info *sbi = F2FS_P_SB(node_page);
+		struct writeback_control wbc = {
+			.sync_mode = WB_SYNC_ALL,
+			.nr_to_write = 1,
+			.for_reclaim = 0,
+		};
+
+		set_page_dirty(node_page);
+		f2fs_wait_on_page_writeback(node_page, NODE, true);
+
+		f2fs_bug_on(sbi, PageWriteback(node_page));
+		if (!clear_page_dirty_for_io(node_page))
+			goto out_page;
+
+		if (NODE_MAPPING(sbi)->a_ops->writepage(node_page, &wbc))
+			unlock_page(node_page);
+		goto release_page;
+	} else {
+		/* set page dirty and write it */
+		if (!PageWriteback(node_page))
+			set_page_dirty(node_page);
+	}
+out_page:
+	unlock_page(node_page);
+release_page:
+	f2fs_put_page(node_page, 0);
+}
+
 static struct page *last_fsync_dnode(struct f2fs_sb_info *sbi, nid_t ino)
 {
 	pgoff_t index, end;
-- 
2.39.5