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From:   Chao Yu <yuchao0@huawei.com>
To:     <jaegeuk@kernel.org>
CC:     <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, <chao@kernel.org>,
        Chao Yu <yuchao0@huawei.com>
Subject: [PATCH] f2fs: add bio cache for IPU
Date:   Tue, 23 Oct 2018 16:38:17 +0800
Message-ID: <20181023083817.3466-1-yuchao0@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

SQLite in Wal mode may trigger sequential IPU write in db-wal file, after
commit d1b3e72d5490 ("f2fs: submit bio of in-place-update pages"), we
lost the chance of merging page in inner managed bio cache, result in
submitting more small-sized IO.

So let's add temporary bio in writepages() to cache mergeable write IO as
much as possible.

Test case:
1. xfs_io -f /mnt/f2fs/file -c "pwrite 0 65536" -c "fsync"
2. xfs_io -f /mnt/f2fs/file -c "pwrite 0 65536" -c "fsync"

Before:
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65544, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65552, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65560, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65568, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65576, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65584, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65592, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65600, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65608, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65616, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65624, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65632, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65640, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65648, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65656, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65664, size = 4096
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), NODE, sector = 57352, size = 4096

After:
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), DATA, sector = 65544, size = 65536
f2fs_submit_write_bio: dev = (251,0)/(251,0), rw = WRITE(S), NODE, sector = 57368, size = 4096

Signed-off-by: Chao Yu <yuchao0@huawei.com>
---
 fs/f2fs/data.c    | 57 +++++++++++++++++++++++++++++++++++++++++++++--
 fs/f2fs/f2fs.h    |  3 +++
 fs/f2fs/segment.c |  5 ++++-
 3 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 01b7f59523dc..0c8f18dc140d 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -491,6 +491,49 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
 	return 0;
 }
 
+int f2fs_merge_page_bio(struct f2fs_io_info *fio)
+{
+	struct bio *bio = *fio->bio;
+	struct page *page = fio->encrypted_page ?
+			fio->encrypted_page : fio->page;
+
+	if (!f2fs_is_valid_blkaddr(fio->sbi, fio->new_blkaddr,
+			__is_meta_io(fio) ? META_GENERIC : DATA_GENERIC))
+		return -EFAULT;
+
+	trace_f2fs_submit_page_bio(page, fio);
+	f2fs_trace_ios(fio, 0);
+
+	if (bio && (*fio->last_block + 1 != fio->new_blkaddr ||
+			!__same_bdev(fio->sbi, fio->new_blkaddr, bio))) {
+		__submit_bio(fio->sbi, bio, fio->type);
+		bio = NULL;
+	}
+alloc_new:
+	if (!bio) {
+		bio = __bio_alloc(fio->sbi, fio->new_blkaddr, fio->io_wbc,
+				BIO_MAX_PAGES, false, fio->type, fio->temp);
+		*fio->last_block = fio->new_blkaddr;
+		bio_set_op_attrs(bio, fio->op, fio->op_flags);
+	}
+
+	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
+		__submit_bio(fio->sbi, bio, fio->type);
+		bio = NULL;
+		goto alloc_new;
+	}
+
+	if (fio->io_wbc)
+		wbc_account_io(fio->io_wbc, page, PAGE_SIZE);
+
+	*fio->last_block = fio->new_blkaddr;
+
+	inc_page_count(fio->sbi, WB_DATA_TYPE(fio->page));
+
+	*fio->bio = bio;
+	return 0;
+}
+
 void f2fs_submit_page_write(struct f2fs_io_info *fio)
 {
 	struct f2fs_sb_info *sbi = fio->sbi;
@@ -1899,6 +1942,8 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio)
 }
 
 static int __write_data_page(struct page *page, bool *submitted,
+				struct bio **bio,
+				sector_t *last_block,
 				struct writeback_control *wbc,
 				enum iostat_type io_type)
 {
@@ -1924,6 +1969,8 @@ static int __write_data_page(struct page *page, bool *submitted,
 		.need_lock = LOCK_RETRY,
 		.io_type = io_type,
 		.io_wbc = wbc,
+		.bio = bio,
+		.last_block = last_block,
 	};
 
 	trace_f2fs_writepage(page, DATA);
@@ -2051,7 +2098,7 @@ static int __write_data_page(struct page *page, bool *submitted,
 static int f2fs_write_data_page(struct page *page,
 					struct writeback_control *wbc)
 {
-	return __write_data_page(page, NULL, wbc, FS_DATA_IO);
+	return __write_data_page(page, NULL, NULL, NULL, wbc, FS_DATA_IO);
 }
 
 /*
@@ -2067,6 +2114,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	int done = 0;
 	struct pagevec pvec;
 	struct f2fs_sb_info *sbi = F2FS_M_SB(mapping);
+	struct bio *bio = NULL;
+	sector_t last_block;
 	int nr_pages;
 	pgoff_t uninitialized_var(writeback_index);
 	pgoff_t index;
@@ -2154,7 +2203,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 			if (!clear_page_dirty_for_io(page))
 				goto continue_unlock;
 
-			ret = __write_data_page(page, &submitted, wbc, io_type);
+			ret = __write_data_page(page, &submitted, &bio,
+						&last_block, wbc, io_type);
 			if (unlikely(ret)) {
 				/*
 				 * keep nr_to_write, since vfs uses this to
@@ -2201,6 +2251,9 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
 	if (nwritten)
 		f2fs_submit_merged_write_cond(F2FS_M_SB(mapping), mapping->host,
 								NULL, 0, DATA);
+	/* submit cached bio of IPU write */
+	if (bio)
+		__submit_bio(sbi, bio, DATA);
 
 	return ret;
 }
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 8932276015f9..6af2a105529d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1042,6 +1042,8 @@ struct f2fs_io_info {
 	bool retry;		/* need to reallocate block address */
 	enum iostat_type io_type;	/* io type */
 	struct writeback_control *io_wbc; /* writeback control */
+	struct bio **bio;		/* bio for ipu */
+	sector_t *last_block;		/* last block number in bio */
 	unsigned char version;		/* version of the node */
 };
 
@@ -3085,6 +3087,7 @@ void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
 				nid_t ino, enum page_type type);
 void f2fs_flush_merged_writes(struct f2fs_sb_info *sbi);
 int f2fs_submit_page_bio(struct f2fs_io_info *fio);
+int f2fs_merge_page_bio(struct f2fs_io_info *fio);
 void f2fs_submit_page_write(struct f2fs_io_info *fio);
 struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
 			block_t blk_addr, struct bio *bio);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 3aa2f00262b3..b51b182dd7f4 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3194,7 +3194,10 @@ int f2fs_inplace_write_data(struct f2fs_io_info *fio)
 
 	stat_inc_inplace_blocks(fio->sbi);
 
-	err = f2fs_submit_page_bio(fio);
+	if (fio->bio)
+		err = f2fs_merge_page_bio(fio);
+	else
+		err = f2fs_submit_page_bio(fio);
 	if (!err)
 		update_device_state(fio);
 
-- 
2.18.0.rc1