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Commit 6d598450 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: fix performance issue observed with multi-thread sequential read 



This reverts the commit - "b93f7712 - 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: default avatarSahitya Tummala <stummala@codeaurora.org>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent b6368629

Documentation/ABI/testing/sysfs-fs-f2fs

+8 −0
Original line number Diff line number Diff line
@@ -51,6 +51,14 @@ Description: 
		 Controls the dirty page count condition for the in-place-update

		 policies.



What:		/sys/fs/f2fs/<disk>/min_seq_blocks

Date:		August 2018

Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>

Description:

		 Controls the dirty page count condition for batched sequential

		 writes in ->writepages.





What:		/sys/fs/f2fs/<disk>/min_hot_blocks

Date:		March 2017

Contact:	"Jaegeuk Kim" <jaegeuk@kernel.org>

fs/f2fs/data.c

+21 −0
Original line number Diff line number Diff line
@@ -2120,6 +2120,18 @@ 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)
@@ -2128,6 +2140,7 @@ 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)
@@ -2158,10 +2171,18 @@ 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]);

	/*

fs/f2fs/f2fs.h

+2 −0
Original line number Diff line number Diff line
@@ -912,6 +912,7 @@ struct f2fs_sm_info { 
	unsigned int ipu_policy;	/* in-place-update policy */

	unsigned int min_ipu_util;	/* in-place-update threshold */

	unsigned int min_fsync_blocks;	/* threshold for fsync */

	unsigned int min_seq_blocks;	/* threshold for sequential blocks */

	unsigned int min_hot_blocks;	/* threshold for hot block allocation */

	unsigned int min_ssr_sections;	/* threshold to trigger SSR allocation */
@@ -1132,6 +1133,7 @@ struct f2fs_sb_info { 
	struct rw_semaphore sb_lock;		/* lock for raw super block */

	int valid_super_block;			/* valid super block no */

	unsigned long s_flag;				/* flags for sbi */

	struct mutex writepages;		/* mutex for writepages() */



#ifdef CONFIG_BLK_DEV_ZONED

	unsigned int blocks_per_blkz;		/* F2FS blocks per zone */

fs/f2fs/segment.c

+1 −0
Original line number Diff line number Diff line
@@ -4128,6 +4128,7 @@ int f2fs_build_segment_manager(struct f2fs_sb_info *sbi) 
		sm_info->ipu_policy = 1 << F2FS_IPU_FSYNC;

	sm_info->min_ipu_util = DEF_MIN_IPU_UTIL;

	sm_info->min_fsync_blocks = DEF_MIN_FSYNC_BLOCKS;

	sm_info->min_seq_blocks = sbi->blocks_per_seg * sbi->segs_per_sec;

	sm_info->min_hot_blocks = DEF_MIN_HOT_BLOCKS;

	sm_info->min_ssr_sections = reserved_sections(sbi);

fs/f2fs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -2846,6 +2846,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) 
	/* init f2fs-specific super block info */

	sbi->valid_super_block = valid_super_block;

	mutex_init(&sbi->gc_mutex);

	mutex_init(&sbi->writepages);

	mutex_init(&sbi->cp_mutex);

	init_rwsem(&sbi->node_write);

	init_rwsem(&sbi->node_change);