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/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 9b0123388f182dfe5829205a73bdf5a63bd32e10..94a24aedcdb237cfe07fb9f4fe0c33e953a49bd5 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -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>

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 43d3723dc8863fed00c376ae2e78886a6776453a..bdcb023506a7a5d892236571f536779ae7b31bd9 100644 (file)
--- 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]);
        /*

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9a6ba4a8d338526df522268e8866bd0c5973f9bc..170573f8a04a389f4a0274d38260150e2870167c 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -913,6 +913,7 @@ 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 */
 
@@ -1133,6 +1134,7 @@ 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 */

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index b136e39e1e9ec868448fab474ddb8e14d909feef..20650e25117b296b01b3aaa541a0552b8654e070 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -4127,6 +4127,7 @@ 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);
 

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index be41dbd7b261d20aac957af79ce01c92692418f7..53d70b64fea1a339a90aeae61ef53ff52424c748 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2842,6 +2842,7 @@ 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);

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index cd2e030e47b88db5bb0a8d8dea2c10675efb1da9..81c0e5337443dee31c5339be2a305f16e91c9ddf 100644 (file)
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -397,6 +397,7 @@ F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_fsync_blocks, min_fsync_blocks);
+F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_seq_blocks, min_seq_blocks);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_hot_blocks, min_hot_blocks);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ssr_sections, min_ssr_sections);
 F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ram_thresh, ram_thresh);
@@ -449,6 +450,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(ipu_policy),
        ATTR_LIST(min_ipu_util),
        ATTR_LIST(min_fsync_blocks),
+       ATTR_LIST(min_seq_blocks),
        ATTR_LIST(min_hot_blocks),
        ATTR_LIST(min_ssr_sections),
        ATTR_LIST(max_victim_search),