[f2fs-dev] [PATCH V2 1/2 RESEND] f2fs: add a new function to supportfor merging contiguous read

[Chao Yu]

For better read performance, we add a new function to support for merging contiguous read as the one for write.

v1-->v2:
 o add declarations here as Gu Zheng suggested.
 o use new structure f2fs_bio_info introduced by Jaegeuk Kim.

Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
Acked-by: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
---
 fs/f2fs/data.c  |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/f2fs/f2fs.h  |    3 +++
 fs/f2fs/super.c |    1 +
 3 files changed, 54 insertions(+)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index b4e4c7e..9cf3f6c 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -400,6 +400,56 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
 	return 0;
 }
 
+void f2fs_submit_read_bio(struct f2fs_sb_info *sbi, int rw)
+{
+	struct f2fs_bio_info *io = &sbi->read_io;
+
+	if (!io->bio)
+		return;
+
+	mutex_lock(&io->io_mutex);
+	if (io->bio) {
+		submit_bio(rw, io->bio);
+		io->bio = NULL;
+	}
+	mutex_unlock(&io->io_mutex);
+}
+
+void submit_read_page(struct f2fs_sb_info *sbi, struct page *page,
+					block_t blk_addr, int rw)
+{
+	struct block_device *bdev = sbi->sb->s_bdev;
+	struct f2fs_bio_info *io = &sbi->read_io;
+	int bio_blocks;
+
+	verify_block_addr(sbi, blk_addr);
+
+	mutex_lock(&io->io_mutex);
+
+	if (io->bio && io->last_block_in_bio != blk_addr - 1) {
+		submit_bio(rw, io->bio);
+		io->bio = NULL;
+	}
+alloc_new:
+	if (io->bio == NULL) {
+		bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
+		io->bio = f2fs_bio_alloc(bdev, bio_blocks);
+		io->bio->bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
+		io->bio->bi_end_io = read_end_io;
+	}
+
+	if (bio_add_page(io->bio, page, PAGE_CACHE_SIZE, 0) <
+							PAGE_CACHE_SIZE) {
+		submit_bio(rw, io->bio);
+		io->bio = NULL;
+		goto alloc_new;
+	}
+
+	io->last_block_in_bio = blk_addr;
+
+	mutex_unlock(&io->io_mutex);
+}
+
 /*
  * This function should be used by the data read flow only where it
  * does not check the "create" flag that indicates block allocation.
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a54fac2..e2cb920 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -368,6 +368,7 @@ struct f2fs_sb_info {
 	struct f2fs_sm_info *sm_info;		/* segment manager */
 
 	/* for bio operations */
+	struct f2fs_bio_info read_io;			/* for read bios */
 	struct f2fs_bio_info write_io[NR_PAGE_TYPE];	/* for write bios */
 
 	/* for checkpoint */
@@ -1118,6 +1119,8 @@ struct page *find_data_page(struct inode *, pgoff_t, bool);
 struct page *get_lock_data_page(struct inode *, pgoff_t);
 struct page *get_new_data_page(struct inode *, struct page *, pgoff_t, bool);
 int f2fs_readpage(struct f2fs_sb_info *, struct page *, block_t, int);
+void f2fs_submit_read_bio(struct f2fs_sb_info *, int);
+void submit_read_page(struct f2fs_sb_info *, struct page *, block_t, int);
 int do_write_data_page(struct page *);
 
 /*
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 344fb86..6d78fff 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -876,6 +876,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->por_doing = false;
 	spin_lock_init(&sbi->stat_lock);
 
+	mutex_init(&sbi->read_io.io_mutex);
 	for (i = 0; i < NR_PAGE_TYPE; i++)
 		mutex_init(&sbi->write_io[i].io_mutex);
 
-- 
1.7.9.5

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