f2fs: fix performance issue observed with multi-thread sequential read
This reverts the commit - "b93f771 - f2fs: remove writepages lock"
to fix the drop in sequential read throughput.
Test: ./tiotest -t 32 -d /data/tio_tmp -f 32 -b 524288 -k 1 -k 3 -L
device: UFS
Before -
read throughput: 185 MB/s
total read requests: 85177 (of these ~80000 are 4KB size requests).
total write requests: 2546 (of these ~2208 requests are written in 512KB).
After -
read throughput: 758 MB/s
total read requests: 2417 (of these ~2042 are 512KB reads).
total write requests: 2701 (of these ~2034 requests are written in 512KB).
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 43d3723..bdcb023 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2122,6 +2122,18 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
return ret;
}
+static inline bool __should_serialize_io(struct inode *inode,
+ struct writeback_control *wbc)
+{
+ if (!S_ISREG(inode->i_mode))
+ return false;
+ if (wbc->sync_mode != WB_SYNC_ALL)
+ return true;
+ if (get_dirty_pages(inode) >= SM_I(F2FS_I_SB(inode))->min_seq_blocks)
+ return true;
+ return false;
+}
+
static int __f2fs_write_data_pages(struct address_space *mapping,
struct writeback_control *wbc,
enum iostat_type io_type)
@@ -2130,6 +2142,7 @@ static int __f2fs_write_data_pages(struct address_space *mapping,
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct blk_plug plug;
int ret;
+ bool locked = false;
/* deal with chardevs and other special file */
if (!mapping->a_ops->writepage)
@@ -2160,10 +2173,18 @@ static int __f2fs_write_data_pages(struct address_space *mapping,
else if (atomic_read(&sbi->wb_sync_req[DATA]))
goto skip_write;
+ if (__should_serialize_io(inode, wbc)) {
+ mutex_lock(&sbi->writepages);
+ locked = true;
+ }
+
blk_start_plug(&plug);
ret = f2fs_write_cache_pages(mapping, wbc, io_type);
blk_finish_plug(&plug);
+ if (locked)
+ mutex_unlock(&sbi->writepages);
+
if (wbc->sync_mode == WB_SYNC_ALL)
atomic_dec(&sbi->wb_sync_req[DATA]);
/*
