[PATCH] f2fs: add bio cache for IPU

From: Chao Yu
Date: Tue Oct 23 2018 - 04:40:43 EST


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@xxxxxxxxxx>
---
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